PHARM Flashcards

Question

Use of which of the following agents increases the risk for developing an oral fungal infection? ``` A. Albuterol inhalation B. Beclomethasone inhalation C. Terbutaline inhalation D. Cromolyn inhalation E. Ipratropium inhalation ```

Answer 1

B. Beclomethasone inhalation: Oral fungal infections can be caused by a number of factors. Patients receiving oral or inhalation corticosteroids, antibiotics, chemotherapy, and local irradiation as well as those with compromised immune systems commonly develop oral fungal infections. Candidiasis is the most common type of fungal infection seen in these patients. Beclomethasone inhalation commonly causes oral fungal infections since it is classified as a corticosteroid. This agent is used in the treatment of bronchial asthma because it decreases inflammation and edema in the respiratory tract. The risk for developing an oral fungal infection when using beclomethasone inhalation can be substantially decreased when individuals rinse out their mouth with water after each usage. - Both albuterol and terbutaline inhalation are used to relieve bronchospasm associated with acute or chronic asthma. These agents are potent beta-2-receptor agonists and cause almost immediate bronchodilation. The major side effects of these agents are tachycardia and CNS stimulation. - Cromolyn inhalation is a mast-cell stabilizing (antihistaminic) agent used primarily for the prophylaxis of mild to moderate seasonal and perennial bronchial asthma and allergic rhinitis. The major disadvantage of this agent is that it has a very slow onset of action; it may take several weeks to achieve a desired effect. Cromolyn has very few side effects and is generally well-tolerated. - Ipratropium inhalation is used to relieve bronchospasm associated with COPD. The major side effects associated with this agent include blurred vision, bitter taste, and cough.

Answer 2

C. Nitroglycerin: Tachycardia, or increased heart rate, is likely to occur when the cardiac muscle is directly stimulated or when there is a relaxation (vasodilation) of vascular smooth muscle leading to a "pooling" of blood in the venous system, as seen in patients receiving nitroglycerin. Nitroglycerin is indicated for the prevention of angina. - The calcium-channel blockers, such as amlodipine, diltiazem, and verapamil, decrease intracardiac contractility; hence, they are not likely to cause tachycardia. - Atenolol is a beta-receptor antagonist that is indicated for the treatment of hypertension and for the treatment of angina since it decreases heart rate. Therefore, this agent is likely to cause bradycardia, not tachycardia.

Answer 3

C. Sulfadiazine: Sulfadiazine is a sulfonamide antibiotic that is a short-acting oral agent associated with a high incidence of crystalluria; therefore, patients must maintain good hydration when receiving this oral medication. This agent is used primarily in the treatment of urinary tract infections. - Silver sulfadiazine is a topical product used primarily for prevention of bacterial colonization of a burn wound. - Sulfacetamide is most commonly used as a topical solution to treat a variety of ophthalmic infections. - Sulfasalazine is an agent used primarily in the treatment of ulcerative colitis. Because intestinal tract absorption is very poor, the incidence of crystalluria is very low. - Sulfasoxazole is a sulfonamide antibiotic that is a short-acting oral agent associated with a low incidence of crystalluria. This agent is used primarily in the treatment of urinary tract infections.

Answer 4

A. Aspiration: When the acidic gastric contents, including undigested foods, are aspirated into the lungs, severe respiratory distress will occur. In some cases, the degree of respiratory distress is so severe that death can occur. Pregnant women are at a higher risk for aspirating the gastric contents into the lungs due to the increased pressure on the stomach. The incidence of aspiration can be dramatically decreased in pregnant women who fast around 8 to 12 hours prior to general anesthesia. Neutralization of the stomach pH is also recommended. Although atelectasis can occur within the first 24 hours after general anesthesia, it is typically not life-threatening. Eclampsia is not a frequent side effect of general anesthesia in pregnant women. Hypotension does not frequently occur with general anesthesia in pregnant women; however, this is a frequent side effect of epidural anesthesia. Visceral pain may occur; however, pain is not considered a life-threatening side effect.

Answer 5

A. AMITRIPTYLINE: Amitriptyline is a tricyclic antidepressant used primarily in the treatment of endogenous depression. It exerts its pharmacologic effects by inhibiting the reuptake of both serotonin and norepinepherine from the presynaptic receptors in the CNS. - Diazepam is a benzodiazepine used in the treatment of various anxiety disorders, in the treatment of status epilepticus, and as a premedication for many different surgical procedures. It binds to the benzodiazepine site on neuronal GABA receptors and enhances GABA-mediated chloride influx. - Fluoxetine is classified as an SSRI (selective serotonin-reuptake inhibitor) antidepressant used in the treatment of depression and various psychotic disorders. It exerts its pharmacologic effects by inhibiting the reuptake of serotonin from the presynaptic receptors in the CNS. - Haloperidol is a butyrophenone antipsychotic used in the management of various psychotic disorders; it is a dopamine-receptor-blocking agent. - Meperidine is an opiate-receptor agonist indicated for the treatment of moderate to severe pain.

Answer 6

C. Fluoxetine: A myocardial infarction results from prolonged myocardial ischemia, precipitated by a decreased perfusion to the myocardial tissue. In most cases, myocardial ischemia is caused by an occlusive coronary thrombus. As a general rule, agents that increase the heart rate or decrease myocardial perfusion are not recommended in patients with a past medical history significant for a myocardial infarction. Fluoxetine is a selective serotonin-reuptake inhibitor (SSRI) used in the treatment of depression and obsessive-compulsive disorders. This agent would be most recommended in a patient who recently experienced a myocardial infarction because it produces little, if any, adverse cardiovascular effects. - Both desipramine and doxepin are tricyclic antidepressants indicated for the treatment of depression. These agents are not recommended for individuals with a recent myocardial infarction because they possess strong anticholinergic effects, which can lead to angina pectoris, conduction disturbances, and sinus tachycardia. - Phenelzine is a monoamine oxidase inhibitor indicated as a second-line agent in the treatment of depression when other, less toxic, agents are unsuccessful. This agent is associated with CNS and cardiac stimulation, blood pressure changes, and orthostatic hypotension. - Trazodone is a tetracyclic antidepressant agent associated with cardiac arrhythmias, tachycardia, and angina pectoris.

Answer 7

A. CEFACLOR: Cefaclor is a second-generation cephalosporin used in the treatment of a variety of upper and lower respiratory infections. This antibiotic has been associated with the development of a serum-like sickness, especially when administered to infants and young adults. The reaction most commonly seen with the agent commonly results in the development of erythema multiforme, rash, and arthralgias. - Chloramphenicol is a broad-spectrum antibiotic used in the treatment of many different infections. This agent is known to cause a disorder called "gray baby syndrome" when given to infants. - Phenobarbital is an anticonvulsant used in the treatment of tonic-clonic seizures; it is associated with the development of agranulocytosis as well as other blood dyscrasias. - Procainamide is a Class IA antiarrhythmic used in the prevention of paroxysmal atrial fibrillation and tachycardia and is associated with the development of systemic lupus erythematous (SLE), which is an inflammatory autoimmune disorder that can affect multiple organ systems. Characteristic signs and symptoms of this disease can include fever, anorexia, malaise, malar rash (butterfly rash), photosensitivity, arthritis, serositis, and various hematological and immunological abnormalities. Other medications associated with the development of SLE include hydralazine, chlorpromazine, isoniazid, methyldopa, and quinidine. - Sulfamethoxazole/trimethoprim is a sulfa antibiotic primarily used in the treatment of urinary tract infections. This agent has been associated with the development of blood dyscrasias, especially in the elderly and in those with some degree of immunosuppression.

Answer 8

A. CNS DYSFXN: Lidocaine is the least likely antiarrhythmic agent to cause cardiac depression but does cause CNS effects, which can range from drowsiness to excitation, culminating in seizures. The drug has vasodilating actions, leading to decreases in blood pressure. It does not cause drug fever or change plasma K+ levels. Lidocaine can have an initial beneficial effect in treating torsades.

Answer 9

C. HALOPERIDOL: A patient presenting with signs and symptoms of Parkinson disease is most likely receiving a medication that blocks the action of dopamine. Remember, Parkinson disease is caused by a relative deficiency of dopamine in the CNS. Of the agents listed, only haloperidol has dopamine-receptor blocking properties. Haloperidol is an antipsychotic indicated for the treatment of a variety of psychotic disorders. One of the major side effects of this medication is the development of Parkinson-like syndrome. It is important to note that drug-induced Parkinson disease is indistinguishable from idiopathic Parkinsonism and is usually reversible in a few weeks upon discontinuation. However, the severity and duration of the signs and symptoms from the drug-induced Parkinson disease is often more pronounced when it occurs in patients with established Parkinson disease. - Cimetidine is an H-receptor antagonist used in the treatment of GERD and gastric ulcers; this agent is generally well tolerated with very little incidence of side effects. - Bumetanide is a loop diuretic indicated for the treatment of various edematous states. This agent is known to cause incontinence and dizziness. - Pirbuterol is a beta-receptor agonist indicated for the treatment of asthma. Although this agent is generally well tolerated with very little incidence of side effects, CNS excitation can occur. - Sucralfate is a basic aluminum salt that forms an ulcer adherent complex at the site of the ulcer and is indicated for the treatment of duodenal ulcer. Constipation is the most common side effect of this agent.

Answer 10

E. Trazodone: Priapism is a condition associated with the development of a painful erection for an extended period of time. When untreated, priapism can cause severe tissue damage that can lead to the development of impotence. Priapism has been reported in patients receiving trazodone for the treatment of depression. In patients with prolonged or inappropriate penile erection, this medication should be discontinued, and medical attention should be sought immediately. Injection of alpha-adrenergic stimulants, such as norepinephrine or epinephrine, may be successful in treating the priapism. Surgical intervention may be necessary. - Atenolol is a beta-receptor blocking agent indicated for the treatment of hypertension; this agent is commonly associated with the development of impotence in males. - Bumetanide is a loop diuretic indicated for the treatment of edema and hypertension; electrolyte abnormalities are the most common side effects seen with this agent. - Glipizide is a sulfonylurea oral hypoglycemic agent indicated for the treatment of type 2 diabetes; hypoglycemia is the most common side effect of this agent. - Paroxetine is a selective serotonin-reuptake inhibitor (SSRI) indicated for the treatment of depression. This agent is commonly associated with the development of impotence in males. With respect to the other SSRls, this agent has the highest incidence of causing impotence in males.

Answer 11

C. SODIUM BICARBONATE: Local anesthetics are used to block pain conduction by nerves. They are commonly used for infiltration anesthesia, local nerve blocks, spinal nerve blocks, and epidural nerve blocks. Local anesthetics inhibit nerve conduction by decreasing the permeability of the neuronal membrane to sodium, which prevents the sodium influx required for propagation of action potentials. Their onset of action is dependent upon the pH at the injection site, lipid solubility, protein binding, and molecular size. Local anesthetics are compounds that have a pH greater than 7. In other words, they can be classified as "basic" compounds. In an acidic environment, the compound will be in an ionized form. With these concepts in mind, the pH at the injection site is important because only the non-ionized form of the local anesthetic can be absorbed into the nerve. Therefore, the addition of a base such as sodium bicarbonate will accelerate the penetration of the nonionized local anesthetic into the nerve sheath. - Epinephrine is commonly used in local anesthetic injections because it causes local vasoconstriction of the surrounding tissue, thereby reducing the rate of lidocaine removal from the local injection site. - The addition of meperidine, an opioid analgesic, would not alter the rate of absorption of the local anesthetic into the nerve. - Sodium chloride is used in anesthetic solutions to adjust the iso-tonicity of the solution. - Sodium metabisulfite is used as a preservative; it does not affect the penetration rate of the local anesthetic into the nerve sheath.

Answer 12

D. TOPICAL ERYTHROMYCIN OINTMENT: Blepharitis is an inflammation of the lid margins that is generally a bilateral and chronic condition. The two main types of blepharitis are staphylococcal and seborrheic. This condition is characterized by redness and irritation of the eyelids. Signs and symptoms range from mild to severe and include crusting, discharge, ocular discomfort, itching, scaling, and photophobia. Staphylococcal blepharitis is common and, when untreated, can lead to chronically red eyelid margins and scarring. Staphylococcal and ulcerative blepharitis are best treated with topical ophthalmic ointments, such as erythromycin, bacitracin, tetracycline, and sulfonamides. The most commonly used treatment is erythromycin ointment. - Intramuscular ceftriaxone: is commonly used for the treatment of gonococcal conjunctivitis. - The most common treatment measures for chlamydial keratoconjunctivitis include either oral erythromycin or oral tetracycline. - Topical ketorolac is commonly used for the treatment of ocular inflammation.

Answer 13

A. AMITRIPTYLINE: Cyclobenzaprine is a centrally acting skeletal muscle relaxant that is structurally and pharmacologically related to tricyclic antidepressants. Cyclobenzaprine is used short-term as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute musculoskeletal conditions. Like tricyclic antidepressants, the most common side effects are dry mouth, drowsiness, dizziness, weakness, fatigue, tachycardia, urinary retention and abdominal cramping. Since amitriptyline is a tricyclic antidepressant, the side effects of cyclobenzaprine would be expected to be most similar to amitriptyline. - Dantrolene is also a centrally acting skeletal muscle relaxant; however, it is structurally and pharmacologically related to hydantoin derivatives, such as phenytoin. Although dantrolene produces the same CNS effects as cyclobenzaprine, it does not produce anticholinergic side effects, such as dry mouth and urine retention. - Ketoprofen is a non-steroidal anti-inflammatory drug used in the treatment of mild to moderate pain caused by inflammation; its most common side effects are intestinal discomfort and dizziness. - Lorazepam is a benzodiazepine used in the management of anxiety disorders and for the short term relief of anxiety. Lorazepam is associated with the development of drowsiness, sedation, dizziness and weakness. - Tetracycline is an antibiotic used primarily in the treatment of various sexually transmitted diseases and acne. Its major side effects include diarrhea, gastrointestinal upset and phototoxicity.

Answer 14

A. bands, not brackets: Even if your memory fails you, use the basic principles of this subject to guide you. Only procedures inducing bacteremia need to be premedicated. Orthodontic bands can cut into gingival tissue and cause significant bleeding and subsequent bacteremia. Therefore, it is recommended that bands, but not brackets be premedicated. Orthodontic brackets (choices B and C) are generally bonded to coronal tooth structure and no bleeding occurs. Choice D is also incorrect.

Answer 15

E. SULFISOXAZOLE: Kernicterus is a disorder caused by high levels of unconjugated bilirubin, a breakdown product of hemoglobin. This neurological disorder is characterized by opisthotonus (a high-pitched cry), abnormal Moro reflex, and abnormal eye movements. The development of kernicterus in an infant can occur when the mother takes sulfonamide antibiotics, such as sulfisoxazole, during pregnancy. - Acetaminophen is a mild analgesic and antipyretic agent that can be safely taken in during pregnancy. - Chloramphenicol is a broad-spectrum antibiotic effective against a wide variety of gram-negative, gram-positive, and anaerobic organisms. The use of this antibiotic in infants is associated with a condition referred to as "gray-baby syndrome". This syndrome is associated with cyanosis, vascular collapse, and elevated drug levels. - Diethylstilbestrol (DES) is an older agent that is sometimes used in estrogen deficiency states and in the treatment of prostatic carcinoma; its use is contraindicated during pregnancy. DES is known to increase the risk of vaginal and/or cervical cancer in the offspring. - Erythromycin is a macrolide antibiotic used for the treatment of a variety of infections; the use is this antibiotic during pregnancy is acceptable.

Answer 16

E. the rate of elimination varies directly with the dose: In first-order kinetics, the elimination rate of a drug is directly proportional to its plasma concentration, which in turn is proportional to the dose (choice E). Hence, choice A is incorrect. Drugs that follow first-order elimination also have constant elimination half-lives (choice B). Likewise, volume (choice C) and clearance (choice D) of distribution are pharmacokinetic characteristics of a drug that do not routinely change with dose, although they may vary in terms of disease or dysfunction.

Answer 17

D. relative potency of the drug: In general, systemic toxicity of local anesthetics is determined by the rate of drug absorption from the injection site in relation to the drug redistribution and metabolism. The extent of the absorption of any drug from the site of injection, including local anesthetics, is dependent on the pharmacokinetic properties of the drug; such as: the chemical structure of the drug (choice A) (i.e. amide or ester), the dose of the medication administered (choice B) (i.e. as the amount of medication administered increases, so does the extent of drug absorption), the presence of epinephrine (choice C), and the vascularity at the injection site (choice E). The relative potency of a medication (choice D) does not affect the extent of the drug's ability to be absorbed at the injection site.

Answer 18

D. Tylenol #3 (acetaminophen with codeine): has few irritative gastric effects. Aspirin (choice B) is always contraindicated in ulcer patients, as are most of its derivatives, like diflunisal (choice E) (Dolobid). Indomethacin (choice A) is an acetic acid derivative with a side effect of GI bleeding. Naproxen (choice C) (Naprosyn) is a propionic acid derivative with bleeding side effects as well.

Answer 19

E. vitamin K-dependent clotting factors: Warfarin is an anticoagulant that exerts its mechanism of action by interfering with the synthesis of the vitamin K-dependent clotting factors (II, VII, IX, X). Its antithrombotic effects are not fully seen until 2 to 5 days (mean of 3 to 4 days) after the first dose. It is indicated for the prophylaxis and treatment of atrial fibrillation with embolism, adjunctive treatment of coronary occlusion, and prophylaxis of systemic embolism (after MI) as well as various other indications. - Cyclooxygenase is an enzyme that is inhibited by aspirin and the nonsteroidal anti-inflammatory drugs (NSAIDs); its production is not affected by warfarin. - Fibrinogen is a precursor of fibrin, which is an elastic filamentous protein that promotes coagulation; fibrinogen production is not affected by warfarin. The production of platelets is not decreased in patients taking warfarin therapy. - Aspirin and the NSAIDs are able to prolong bleeding time by the acetylation of platelet cyclooxygenase, which decreases the synthesis of thromboxane A2. Thromboxane A2, a prostaglandin derivative, is a potent vasoconstrictor and inducer of platelet aggregation.

Answer 20

A. Amantadine is an agent used in the treatment of Parkinson disease as an initial agent or in combination with other anti-Parkinson agents. Amantadine is also used for the symptomatic treatment of influenza A infections because of its antiviral properties. - Bromocriptine is a dopamine agonist used as an adjunctive agent to levodopa in the treatment of Parkinson disease. It is also used in the short-term management of amenorrhea/galactorrhea or female infertility associated with hyperprolactinemia. - Carbidopa has no pharmacologic action for the treatment of Parkinson disease; however, it does decrease the metabolism of levodopa in the body. - Levodopa is the most effective agent available for the treatment of Parkinson disease. It is decarboxylated to dopamine in the brain. Remember, dopamine deficiency is the etiology for Parkinson disease. - Selegiline is effective for the treatment of Parkinson disease because it inhibits the intracerebral metabolic degradation of dopamine by irreversibly inhibiting monoamine oxidase type B.

Answer 21

C. Lidocaine: Both mexiletine and tocainide are classified as class IB antiarrhythmic agents that shorten the action potential duration and refractory period and improve the resting potential duration. They produce a modest suppression of sinus node automaticity as well as AV node conduction. Lidocaine is also classified as a class IB antiarrhythmic. Esmolol is a class II antiarrhythmic agent that exerts its action as an ultra-short acting beta 1-adrenergic blocking agent with cardioselective properties. Both disopyramide (choice B) and quinidine (choice D) are class IA antiarrhythmics. They depress myocardial excitability, conduction velocity, contractility, and automaticity. They also prolong effective refractory period and block vagal stimulation of the AV node. Verapamil (choice E) is a calcium channel blocking agent and a class IV antiarrhythmic agent. As an antiarrhythmic, verapamil decreases and slows SA and AV node conduction. ``` • Class I: Na channel blockers (NCBs) o IA: (ADPQ) depress myocardial excitability, conduction velocity, contractility, automaticity, prolong effective refractory period & block vagal stimulation of AV node ♣ Amiodarone(cordarone) ♣ Disopyramide(norpace) = prolong AP ♣ Procainamide(procan sr): side- SLE ♣ Quinidine(quinidex): side- SLE o IB: (LMT) shorten AP ♣ Lidocaine(xylocaine) ♣ Mexiletine(mexitil) ♣ Tocainide(tonocard) o IC: Flecainide(tambocor), Propafenone(rhythmol) = no AP effect ``` ``` • Class II: ultra-short acting beta1-adrenergic blocking agents w/ cardioselective properties; increase refractory period, decrease conduction velocity, reduce automaticity o Acetbutolol(sectral) o Esmolol(brevibloc) o Metoprolol(Lopressor): o Propranolol(Inderal) ``` ``` • Class III: K+ channel blockers (KCBs) o Amiodarone(cordarone), Sotalol(betapace), Ibutilide(corvert), Dofetilide(tikosyn) = increase refractory period, reduce automaticity ``` • Class IV: CCBs – indirect vasodilators (Diltiazem, Nifedipine, Verapamil), antiarrhythmic agent- decreases & slows SA&AV node conduction o Verapamil(calan), Diltiazem = increase refractory period, decrease conduction velocity & automaticity ♣ Verapamil: strong negative ionotropic, side- hypotension & dizziness

Answer 22

E. AMOXICILLIN: Theophylline is a xanthine derivative that relaxes smooth muscle by direct action. The smooth muscles in the bronchi and pulmonary vessels are particularly affected. This agent also stimulates the respiratory center. Theophylline is commonly used for prophylaxis and symptomatic relief of bronchial asthma. This agent is extensively metabolized by the liver. Therefore, any agent that inhibits liver metabolism would increase the blood level of theophylline in the body, which would potentiate the effects of theophylline as well as its adverse effects. - Clarithromycin and erythromycin are macrolide antibiotics commonly used in the treatment of upper respiratory infections, skin, and skin structure infections. They decrease theophylline clearance by inhibiting cytochrome P450 3A3. Therefore, they are likely to potentiate the toxic effects of theophylline. - Ciprofloxacin may result in a 50% to 60% increase in serum theophylline levels. It decreases theophylline clearance by inhibiting cytochrome P450 1A2. However, the newer fluoroquinolones (moxifloxacin, gemifloxacin, gatifloxacin, levofloxacin, and trovafloxacin) do not interfere with theophylline metabolism. - Cimetidine decreases theophylline clearance by inhibiting cytochrome P450 1A2. Therefore, it is likely to potentiate the toxic effects of theophylline. Doxycycline and amoxicillins do not have any reported interaction with theophylline

Answer 23

D. METOPROLOL: Metoprolol is a beta-adrenergic blocking agent that is known to cause dyslipidemias and worsen coexisting dyslipidemias. All of the other medications are not associated with the development of dyslipidemias. - Captopril, an ACE inhibitor, and verapamil, a calcium-channel blocker, are both "first-line agents" used to treat essential hypertension; they are not associated with the development of dyslipidemias. - Both clonidine, a centrally acting alpha-receptor agonist, and terazosin, a peripherally acting alpha-receptor-blocking agent, can be used to treat hypertension. However, due to their side effect profiles, these agents are generally used in patients unresponsive to other antihypertensive therapies.

Answer 24

B. Angina pectoris: There are many congenital and acquired conditions that require antibiotic premedication, including hypertrophic cardiomyopathy, tetralogy of Fallot, and prosthetic cardiac valves. Those that DO NOT require antibiotic premedication include angina pectoris, cardiac bypass surgery, cardiac pacemakers, and previous myocardial infarction.

Answer 25

C. CIPROFLOXACIN: Ciprofloxacin is a fluoroquinolone antibiotic indicated for the treatment of a wide variety of infections caused by both gram-negative and gram-positive organisms. This agent and other fluoroquinolone antibiotics are associated with the development of signs and symptoms of arthropathy when administered to children under the age of 18. - Cefaclor is a second-generation cephalosporin used in the treatment of a variety of upper and lower respiratory infections. This antibiotic been associated with the development of a serum-like sickness, especially when administered to infants and young adults. The reaction most commonly seen with the agent is the development of erythema multiforme with rash as well as arthralgias. - Chloramphenicol is a broad-spectrum antibiotic used in the treatment of many different infections. This agent is known to cause the disorder called "gray baby syndrome" when given to infants. - Procainamide is a Class 1A antiarrhythmic (not an antibiotic) used in the prevention of paroxysmal atrial fibrillation and tachycardia and is associated with the development of systemic lupus erythematous (SLE), which is an inflammatory autoimmune disorder that can affect multiple organ systems. Characteristic signs and symptoms of this disease can include fever, anorexia, malaise, malar rash (butterfly rash), photosensitivity, arthritis, serositis, and various hematologic and immunologic abnormalities. Other medications associated with the development of SLE include procainamide, hydralazine, chlorpromazine, isoniazid, methyldopa, and quinidine. - Sulfamethoxazole/trimethoprim is a "sulfa" antibiotic primarily used in the treatment of urinary tract infections. This agent has been associated with the development of blood dyscrasias, especially in the elderly and in those with some degree of immunosuppression.

Answer 26

B. STREPTOMYCIN: Streptomycin is an inhibitor of the 30S subunit of the bacterial ribosome and is in the aminoglycoside family of antibiotics with neomycin, gentamicin, and amikacin. It is effective only for aerobic infections and is sometimes used as an antimycobacterial. It is administered intravenously or intramuscularly, and it is sometimes used in combination with beta-lactam-type antibiotics. Amoxicillin, clarithromycin, clindamycin, and metronidazole can all be administered.

Answer 27

A. ATORVASTATIN: At clinically relevant doses, the lipid-lowering potential is as follows (from greatest to least potential): - Atorvastatin - Simvastatin - Lovastatin - Pravastatin - Fluvastatin All of these agents are reversible, competitive inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. This enzyme is the rate-limiting enzyme in cholesterol biosynthesis. HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, a cholesterol precursor, in the liver. Inhibition of the enzyme leads to a decrease in the serum LDL level.

Answer 28

C. HCTZ: The patient has a past medical history significant for "sulfa" allergies; therefore, he should not be prescribed any medications that contain sulfur or chemically related compounds, such as thiazide diuretics. Because hydrochlorothiazide is a thiazide diuretic, the patient is most likely to have an allergic reaction to this medication. All of the other answer choices can be safely administered to this patient. - Acetaminophen possesses analgesic and antipyretic effects with no anti-inflammatory properties. - Aspirin is a salicylate with analgesic, antipyretic, and anti-inflammatory properties. - Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, antipyretic, and anti-inflammatory properties. - Terazosin is an alpha-1-receptor blocking agent used in the treatment of hypertension and prostatic hypertrophy. This agent is most commonly associated with the development of hypotension.

Answer 29

C. LISINOPRIL: ACE inhibitors (e.g., lisinopril) prevent the conversion of angiotensin I to angiotensin II, and lower blood pressure by decreasing the formation of aldosterone and reducing vasoconstrictive action of Angiotensin II at AT-1 receptors. ACE inhibitors also inhibit the metabolism of bradykinin, and this leads to additional hypotensive effects because bradykinin is an endogenous vasodilator. - Clonidine lowers blood pressure and heart rate by relaxing the arteries and increasing the blood supply to the heart. - Diazoxide reduces peripheral vascular resistance and blood pressure as a result of a direct vasodilatory effect on smooth muscles in peripheral arterioles. - Losartan and propranolol potentiates the effect of Bradykinin; however, this effect is most likely to occur with ACE inhibitors.

Answer 30

A. HYPERKALEMIA: The angiotensin-converting enzyme (ACE) inhibitors are indicated for the treatment of hypertension, heart failure, myocardial infarction, and diabetic nephropathy. With respect to heart failure, ACE inhibitors improve hemodynamic measures and congestive symptoms, reduce cardiovascular events and hospitalization, and improve survival (i.e., decrease morbidity and mortality). Before starting therapy, it is recommended that the patient's electrolyte status be monitored because the ACE inhibitors are known to cause hyperkalemia. In fact, these agents are contraindicated if the patient's serum potassium levels exceed 5.5 mmol/L.

Answer 31

B. Slightly acidic: Local anesthetics must be ionized in order to function inside the neuron, but unionized in order to pass through the fatty cell membrane of the neuron. Anesthetics are first treated with hydrochloric acid to ionize them and to help increase storage life of both anesthetic and vasoconstrictor. When the anesthetic is injected into tissue, tissue buffers neutralize the ions and a free base is formed. This unionized free base freely enters the cell membrane. Within the cell, the slightly acidic environment inside the neuron causes ionization once again into a charged form, which attaches to sodium channels and blocks the entrance of sodium ions, thus preventing action potentials and nerve impulses.

Answer 32

C. NIFEDIPINE: Angina is a condition characterized by a "pain in the chest" secondary to a decreased amount of oxygen supply to the myocardial tissue. Nitrates, beta-receptor blockers, and calcium channel blockers are used in the treatment of angina. Nifedipine, a calcium channel antagonist, is most likely to cause tachycardia when used in the treatment of angina. Inhibition of calcium in arterial smooth muscle is associated with decreased arterial tone and decreased arterial pressure. The reduction in arterial pressure results in reflex tachycardia. - However, other calcium channel blockers, such as diltiazem and verapamil, also decrease intracardiac contractility. Verapamil and diltiazem have more pronounced effects on calcium channels of the myocytes as well as of the cardiac pacemaker and atrioventricular conduction cells, leading to a negative inotropic effect and reduction of heart rate. Therefore, these agents are less likely to cause tachycardia. - Both metoprolol and propranolol are beta-receptor antagonists. These agents are successfully used in the treatment of angina since they decrease heart rate, hence decreasing myocardial oxygen demand. In other words, these agents are more likely to cause bradycardia, not tachycardia. - The interaction of phenytoin (anticonvulsant), cyclosporine (immunosuppressant), and nifedipine (calcium channel blocker) with epithelial keratinocytes, fibroblasts, and/or collagen can lead to gingival hyperplasia in susceptible individuals. Phenytoin causes gingival hyperplasia by its interaction with a subpopulation of sensitive fibroblasts. Potential risk factors for drug-induced gingival hyperplasia include the following: ``` Poor oral hygiene Periodontal disease Periodontal pocket depth Gingival inflammation Degree of dental plaque Duration and dose of medication ```

Answer 33

A. HYPOCALCEMIA: Thiazide diuretics such as hydrochlorothiazide are sulfonamide derivatives that promote diuresis by inhibiting reabsorption of sodium chloride primarily in the early distal tubule. Thiazide diuretics decrease the excretion of calcium; therefore, these agents could theoretically be used in the treatment of hypocalcemia. Because these drugs increase the renal elimination of chloride, potassium, magnesium, and sodium, they promote the development of hypochloremia, hypokalemia, hypomagnesemia, and hyponatremia, respectively.

Answer 34

C. ERYTHROMYCIN: Erythromycin acts on the 50S subunit of bacterial ribosomes. All penicillins, such as methicillin, and cephalosporins, such as cephalexin, prevent NAG-NAM cross-linkages in bacterial cell walls. Both vancomycin and bacitracin are cell-wall inhibitors, but neither works by inhibiting NAG-NAM cross-linkages.

Answer 35

C. GANCICLOVIR: Ganciclovir is effective against many herpes family viruses, including herpes simplex virus 1 (HSV-1), HSV-2, Epstein-Barr virus (EBV), varicella-zoster virus (VZV), and cytomegalovirus (CMV). In particular, it is used to treat HIV-associated CMV retinitis. - A major difference from acyclovir is that acyclovir is not effective against CMV. - Sulfamethoxazole/trimethoprim inhibits folic acid synthesis in bacteria and is used to treat Pneumocystis carinii (now known as P. jiroveci) pneumonia. - Clotrimazole is an imidazole antifungal used to treat candidiasis. - Zidovudine, also known as AZT, is a reverse transcriptase inhibitor used to treat HIV infection.

Answer 36

D. ERYTHROMYCIN: Theophylline is a xanthine derivative that relaxes smooth muscle by direct action. The smooth muscles in the bronchi and pulmonary vessels are particularly affected. This agent also stimulates the respiratory center. Theophylline is commonly used for prophylaxis and symptomatic relief of bronchial asthma. This agent is extensively metabolized by the liver. Therefore, any agent that inhibits liver metabolism would increase the blood level of theophylline, which would potentiate the effects of theophylline as well as its adverse effects. Erythromycin is a macrolide antibiotic commonly used in the treatment of upper respiratory, skin, and skin structure infections. This agent is a hepatic microsomal enzyme inhibitor. Therefore, erythromycin is likely to potentiate the effects of theophylline. The other agents generally do not interact with theophylline. Ampicillin is a "penicillin" antibiotic used to treat a variety of infections caused by many different organisms. Cefpodoxime is a third-generation cephalosporin used commonly to treat otitis media as well as upper and lower respiratory infections. Chloramphenicol is an anti-infective commonly used to treat severe infections when less toxic agents are not indicated. Tetracycline is a "tetracycline" antibiotic commonly used in the treatment of acne and various sexually transmitted diseases.

Answer 37

B. CHLORAMPHENICOL: Three significant side effects are associated with chloramphenicol. - dose-dependent pancytopenia (bone marrow inhibition). - non-dose-dependent effect on bone marrow, which can be fatal (aplastic anemia). - "gray baby syndrome," a liver failure in fetuses that may occur when the pregnant mother takes chloramphenicol. It is unlikely that metronidazole, bacitracin, clindamycin, or sulfamethoxazole will cause aplastic anemia, although each drug may have other possible side effects.

Answer 38

A. METOPROLOL: One of the primary methods of treatment for an asthmatic patient is use of a beta-2-receptor agonist such as albuterol. When this agent is used, one will see bronchodilation. However, when an agent with beta-2-receptor blocking properties is prescribed, the patient will experience worsening of the asthma signs and symptoms secondary to bronchoconstriction. For this reason, beta-receptor-blocking agents should be avoided in patients with asthma. However, if a patient with asthma needs to be prescribed a beta-blocker for the treatment of hypertension, this patient should be prescribed a beta-1-selective blocking agent, such as Metoprolol or Atenolol. Because all the other agents, including nadolol, sotalol, propranolol, and timolol are all nonselective beta-blocking agents, they should not be used in this patient.

Answer 39

A. AMITRIPTYLINE: Amitriptyline is a tricyclic antidepressant commonly used in the treatment of the depressive periods for bipolar patients; it has no effect on the manic phase of bipolar disorder. When amitriptyline is taken orally, it blocks acetylcholine receptors in the salivary glands and thereby reduces drooling. - Buspirone is an anxiolytic used in the treatment of mild anxiety disorders and would not be effective in the treatment of mania. Buspirone therapy may cause arthralgia, muscle cramps or stiffness, salivation, facial edema, and dysgeusia. - Clozapine is indicated only in the management of severely ill schizophrenic patients who have failed to respond to other neuroleptic agents. Sialorrhea is a very disturbing adverse effect that develops in the early period of clozapine treatment. Excess saliva causes pooling in the oral cavity, and this leads to overflow of saliva from mouth. - Haloperidol is an antipsychotic drug used to treat psychotic disorders like schizophrenia, to control motor (movement) and verbal (for example, Tourette syndrome) tics and is used to treat severe behavior problems in children. It causes drooling. - Pilocarpine is a cholinergic agonist that causes drooling of saliva. It is used to treat dry mouth.

Answer 40

B. number of drops administered to the eye: The eye is one of the most delicate organs found within the human body. Therefore, the formulations used in the treatment of ophthalmic infections must be designed to ensure that minimal irritation occurs while maintaining clinical efficacy. Furthermore, proper treatment of ophthalmic infections is essential to ensure that damage does not occur to the eye. After the topical application of a drug to the eye, the rate and extent of ophthalmic drug absorption is dependent upon all of the following: (1) the amount of drug binding to the proteins on the surface of the eye (this concept is very important because only unbound drugs can be absorbed and/or exert their clinical effect); (2) the rate and extent of nasolacrimal drainage (as the amount of nasolacrimal drainage increases, the amount of drug absorption decreases); and (3) the total amount of time that the drug remains in the cul-de-sac of the eye (as the time increases, so does the potential for drug absorption). The time that the drug remains in contact with the eye can be increased by increasing the viscosity of the ophthalmic preparation. The number of drops administered to the eye has no effect on the rate and extent of ophthalmic drug absorption because the eye can only hold less than 50% of one drop. Therefore, if two or three drops are administered, the remainder will be discarded.

Answer 41

B. CAPTOPRIL: Angioedema is a well-demarcated localized edema involving the deeper layers of the skin, including the subcutaneous tissue. This condition is seen with the ACE inhibitors, particularly: - captopril - enalapril - lisinopril. Atenolol is a beta-1-selective receptor-blocking agent that is associated with the development of bradycardia, dizziness, and impotence in men. Indapamide and hydrochlorothiazide are thiazide diuretics known to cause glucose intolerance in diabetics, electrolyte abnormalities, and photosensitivity. Verapamil is a calcium-channel blocker with strong negative inotropic effects and can cause hypotension and dizziness.

Answer 42

C. NEUTRAL: Prior to injection, the anesthetic solution in a carpule is in a slightly acidic and ionized form. When the solution is injected into the tissue, the slightly alkaline tissue fluids neutralize the anesthetic to the free base form. The alkalization of the anesthetic to the nonionized form improves the ability of the drug to enter into the neuron cell membrane. Once it is inside the neuron, it re-ionizes and attaches to the sodium channels to prevent sodium influx.

Answer 43

C. VitB1: Thiamin or vitamin B1 deficiency can result in the development of beriberi, which is associated with anorexia, muscle cramps, paresthesias, and high output heart failure as well as sensory and motor nerve impairment. A deficiency of vitamin C or ascorbic acid is associated with the development of scurvy, a condition associated with malaise, weakness, perifollicular hemorrhages, bleeding gums, and impaired wound healing. Deficiencies of vitamin A often result in the development of nyctalopia or night blindness. Niacin or vitamin B3 deficiency is associated with the development of a condition known as pellagra. The classic triad of symptoms seen with pellagra is dermatitis, diarrhea, and dementia. The hallmark of cyanocobalamin or vitamin B12 deficiency is pernicious anemia. This megaloblastic anemia may be severe, with a hematocrit as low as 10%. Megaloblastic anemia is also associated with changes in mucosal cells, leading to glossitis, as well as various other gastrointestinal disturbances, such as anorexia and diarrhea.

Answer 44

C. Acute psychiatric instability: Opioid analgesics, such as morphine, mimic endogenous endorphins and enkephalins in the CNS at opiate receptors. They work by increasing the pain threshold and raising pain tolerance. Opioids are effective in the treatment of many different types of pain. Opioids also work centrally to inhibit the cough reflex. Diphenoxylate is an opioid commonly used in the treatment of diarrhea. One of the major side effects of opioids is constipation. Most opioids could be used to treat diarrhea; however, due to their side effect profile, only diphenoxylate is used in the treatment of diarrhea. Opioids are primarily used in the treatment of pain and can be used to decrease the pain and anxiety associated with surgery or trauma. They can be effectively used as a preanesthetic medication. Furthermore, opioids often permit a reduction in the amount of general anesthetic required for surgical anesthesia. Absolute contraindications to opioids include: - severe respiratory instability - acute psychiatric instability or uncontrolled suicide risk.

Answer 45

A. CIMETIDINE: Cimetidine is an H2-receptor antagonist indicated for the short-term and maintenance treatment of duodenal and gastric ulceration as well as for gastroesophageal reflux disease (GERD). One of the primary disadvantages of using this agent instead of the other H2-receptor antagonists, such as famotidine, nizatidine, and ranitidine, is that this agent is a relatively potent hepatic enzyme inhibitor. Therefore, the potential for drug interactions with other medications metabolized by the liver exists. The other H2-receptor antagonists are not potent hepatic enzyme inhibitors. Omeprazole is a gastric acid proton-pump inhibitor indicated for the short-term and maintenance treatment of duodenal and gastric ulceration as well as GERD; it does not affect the hepatic enzymes.

Answer 46

B. AZITHROMYCIN: The Food and Drug Administration (FDA) has established a set of pregnancy categories to determine the rational use of any medication that requires a risk versus benefit assessment. Regardless of the designated Pregnancy Category or presumed safety, no medication/drug should be administered during pregnancy unless it is clearly needed, and the potential benefits outweigh the potential hazards to the fetus. Azithromycin is classified as Pregnancy Category B. You do not need to know the pregnancy category of all drugs.

Answer 47

C. 600 mg 30 minutes to 1 hour before: Clindamycin is the primary oral antibiotic substitute for amoxicillin in the penicillin-allergic patient. Others include azithromycin, clarithromycin, cefadroxil, and cephalexin. Clindamycin is given 600 mg 30 minutes to 1 hour before the procedure. The children's dose is 20 mg/kg.

Answer 48

D. inhibition of Na+/K+/ATPase: Cardiac glycosides increase contractility by inhibiting the Na+/K+/ATPase pump, causing an increase in intracellular Na. This, in turn, increases intracellular Ca by slowing down Na+/Ca2+ exchange. The increase in intracellular Ca2+ leads to its binding to the troponin-tropomyosin complex, causing an allosteric change and facilitating the interaction. Digoxin may indirectly inhibit an increase of adenylyl cyclase in other tissues. Digoxin activates sarcoplasmic reticulum Ca(2+) release channels -- a possible role in cardiac inotropy.

Answer 49

B. ORAL TETRACYCLINE: Chlamydial keratoconjunctivitis is a major cause of blindness worldwide. This condition is associated with recurrent episodes of infection in children and is often manifested as a bilateral follicular conjunctivitis. The diagnosis is made using the Giemsa-stained conjunctival scrapings. The most common treatment measures include either oral tetracycline or oral erythromycin. - Intramuscular ceftriaxone is commonly used for the treatment of gonococcal conjunctivitis. - Vancomycin is most commonly used for the treatment of pseudomembranous colitis. - Topical ketorolac is commonly used for the treatment of ocular inflammation. - Topical naphazoline is most commonly used for the treatment of symptomatic allergic conjunctivitis.

Answer 50

C. CARBAMAZEPINE: Trigeminal neuralgia, otherwise known as tic douloureux, is a condition characterized by excruciating paroxysms of pain in the lips, gums, chin, and cheek. The intense pain typically lasts for no more than a minute or two; however, the pain can be so intense that the patient winces. Tic douloureux is the most striking disorder of trigeminal nerve function. The most effective treatment for trigeminal neuralgia is the antiepileptic agent carbamazepine. In addition to carbamazepine, phenytoin can also be used to effectively treat trigeminal neuralgia. - Alprazolam, a short-acting benzodiazepine, is indicated for the management of a variety of anxiety disorders. - Buspirone is a non-sedating anxiolytic primarily used in the management of anxiety disorders and for short-term treatment of generalized anxiety. - Cefixime is a third-generation cephalosporin antibiotic primarily used in the treatment of upper respiratory infections as well as ear infections. - Neostigmine is a reversible cholinesterase inhibitor used in the prevention and treatment of postoperative abdominal distention and urinary retention. It is also used to reverse the effects of nondepolarizing muscle relaxants, such as tubocurarine.

Answer 51

A. increasing the force of contraction: In therapeutic doses, digitalis affects the cardiac muscle. The principal effect of digitalis is its positive inotropic action or, in other words, it increases the force of myocardial contraction. This will increase cardiac output and decrease venous pressure and blood volume. In addition, it will cause diuresis and relief of edema. Digitalis decreases the refractory period of the atrial myocardium through a direct and indirect effect (vagotonic and vagomimetic). It also decreases the refractory period of the ventricular myocardium. Finally, digitalis can depress the rate of impulse formation and propagation.

Answer 52

D. 180mg: 2 percent lidocaine contains 2 grams lidocaine per each 100 ml of solution. 2 grams equals 2,000 mg. So, we have 2,000 mg per 100 ml of anesthetic solution. Reducing by 100, we get 20 mg lidocaine for each 1 ml of solution. Multiplying by 1.8 for a standard carpule, we get 36 mg lidocaine per 1.8 ml of solution. 5 carpules should have 5 times 36 mg or 180 mg of lidocaine.

Answer 53

E. CEFIXIME: Cefixime is a third-generation cephalosporin commonly used to treat various infections caused by gram-negative organisms. A general rule to remember about cephalosporins is: when progressing from first generation to third generation, the gram-negative activity is increased and the gram-positive activity is decreased. Therefore, first-generation cephalosporins have the most activity against gram-positive organisms and third-generation cephalosporins have the greatest activity against gram-negative activity. - 1st gen: Cephalexin; g(+) - 2nd gen: Cefaclor - Vancomycin: is an antibiotic with excellent g(+) activity. - Metronidazole is an antibiotic with excellent anaerobic bacterial coverage.

Answer 54

B. 2.0 gram, 30 minutes to 1 hour before procedure: Oral cephalexin and cefadroxil doses are the same as those for amoxicillin, 2.0 gram 30 minutes to 1 hour before procedure, children 50 mg/kg. The IM and IV cefazolin dosage is 1.0 gram 30 minutes to 1 hour before procedure.

Answer 55

A. OXYCODONE: Opioid analgesics are commonly used in combination with acetaminophen for the treatment of moderate to severe pain. The majority of compounds related to morphine can cause: respiratory depression, euphoria, drowsiness, nausea, vomiting, peripheral vasodilation, decreased peripheral resistance, orthostatic hypotension, inhibition of peristalsis, and urinary retention. The potency (relative strength) of each compound is related to the number of milligrams of each substance needed to produce the desired and adverse effects. For example, 5 milligrams of oxycodone will produce more analgesia, euphoria, and other side effects than 5 milligrams of hydrocodone. In relation to the narcotic analgesics listed in this question, the relative strengths are as follows: - oxycodone - hydrocodone - codeine - propoxyphene Narcotic antagonists like naloxone block the opioid receptors and inhibit the desired and adverse effects. Naloxone has minimal analgesic properties.

Answer 56

C. PHARMACOKINETIC: There are three primary types of drug interactions: pharmacokinetic, pharmacodynamic, and pharmaceutical. - pharmacokinetic interaction: one drug alters the concentration of another in the blood secondarily by affecting the absorption, distribution, metabolism, or excretion of the other medication. In this case, the patient is receiving erythromycin, which is a hepatic enzyme inhibitor. This agent decreases the metabolism of warfarin, leading to an increased warfarin blood level. - pharmacodynamic interaction: one drug alters the action of another drug without affecting the blood levels of the other medication. For example, if alcohol is ingested with a benzodiazepine, there will be a dramatic increase in the amount of drowsiness experienced by the patient. - pharmaceutical interaction, there is a chemical or physical interaction between two or more drugs before they enter the body. For example, when iron and tetracycline are taken together, these agents "bind" in the intestinal tract, which prevents the absorption of both medications.

Answer 57

A. CEFAZOLIN: As a "subclass" of antibiotics, the third-generation cephalosporins are able to effectively penetrate the blood-brain barrier. However, the first- and second-generation cephalosporins are for the most part unable to penetrate into the CNS. - 1st gen: Cefazolin - 3rd gen: Cefixime, Cefpodoxime, Ceftazidime, Ceftibuten

Answer 58

C. METOCLOPRAMIDE: The patient is presenting with signs and symptoms of Parkinson disease, specifically an exacerbation of his condition secondary to the administration of metoclopramide. The mechanism of this side effect is related to metoclopramide's antagonism of the dopamine receptors. Metoclopramide is a prokinetic agent indicated for the treatment of gastroesophageal reflux disease (GERD) and diabetic gastroparesis. It is important to note that drug-induced Parkinson disease is indistinguishable from idiopathic Parkinsonism and is usually reversible in a few weeks upon discontinuation of medication. However, the severity and duration of the signs and symptoms from the drug-induced Parkinson disease are often more pronounced when they occur in patients with established Parkinson disease. In addition to the development of Parkinson-like symptoms, metoclopramide is also associated with the development of extrapyramidal symptoms and tardive dyskinesia. - Both Cimetidine and Nizatidine are H2-receptor antagonists used in the treatment of GERD and gastric ulcers; these agents are generally well tolerated with very little incidence of side effects. - Lansoprazole is a proton-pump inhibitor indicated for the treatment of gastric ulcerations and GERD; this agent is generally well tolerated with very little incidence of side effects. - Sucralfate is a basic aluminum salt that forms an ulcer adherent complex at the site of the ulcer and is indicated for the treatment of duodenal ulcers. Constipation is the most common side effect.

Answer 59

D. Penicillins possess narrow gram-negative and gram-positive bacterial coverage: With respect to the penicillin antibacterial class of antibiotics, these agents possess narrow gram-negative and broad gram-positive bacterial coverage. Central nervous system penetration is best when inflammation is present, which is particularly important with treating a patient with meningitis. Although these agents are bactericidal antibiotics at established blood levels, inadequate penicillin blood levels can produce bacteriostatic effects. With respect to their mechanism of action, penicillins inhibit the biosynthesis of cell wall mucopeptide. There is a small chance that a patient allergic to penicillin will be allergic to a cephalosporin.

Answer 60

B. Gentamicin: Tubocurarine is a non-depolarizing skeletal muscle relaxant used to induce skeletal muscle relaxation and as an adjunct to general anesthesia. Aminoglycoside antibiotics, such as gentamicin and amikacin, may produce neuromuscular blockade, which enhances the blockade produced by skeletal muscle relaxants, like tubocurarine. The danger of enhancing tubocurarine's effects is that the severity of respiratory depression associated with this agent may be substantially increased. The other agents may be used safely with tubocurarine. - Aspirin is a salicylate analgesic commonly used in the treatment of mild to moderate pain. - Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) used for the treatment of pain caused by inflammation. Indomethacin is one of the strongest NSAIDs available. - Oxycodone is a narcotic analgesic commonly used in the treatment of moderate to severe pain. - Penicillin is an antibiotic used in the treatment of infections caused by susceptible bacterial strains of streptococci, pneumococci and staphylococci.

Answer 61

B. Hypoglycemia: Prednisone is a glucocorticoid with profound anti-inflammatory effects. It is indicated for the treatment of rheumatic disorders, allergic states, endocrine disorders, various dermatological disorders, and respiratory diseases. Among the many endocrine effects of prednisone, it is known to cause hyperglycemia in all patients, especially diabetic patients. In fact, diabetic patients on chronic prednisone therapy often require an increased daily dosage of either insulin or their oral hypoglycemic agents. All of the other adverse effects are associated with chronic usage of prednisone. Edema often occurs since prednisone causes both sodium and water retention. Some degree of immunosuppression often occurs with chronic usage. In fact, it is recommended that patients not receive live vaccines while taking chronic prednisone therapy. Muscle weakness, steroid myopathy, loss of muscle mass, and tendon rupture have all occurred with chronic use of glucocorticoids. Peptic ulcer and gastrointestinal distress are two of the most common side effects associated with chronic prednisone usage.

Answer 62

A. CARDIAC ARRHYTHMIAS: Phenytoin has antiarrhythmic properties similar to those of lidocaine. In the treatment of depression, antidepressants usually inhibit the reuptake of norepinephrine and/or serotonin; phenytoin does not have this property. Agents that are converted to dopamine or possess dopamine agonist properties are used to treat Parkinson's disease. Phenytoin does not possess any properties to treat asthma.

Answer 63

A. reducing epinephrine exposure through the use of lidocaine with 1:50,000 instead of 1:100,000 epinephrine: Epinephrine acts to increase blood pressure, so we want to minimize its use. Mepivacaine (Carbocaine) 3% can be used without vasoconstrictor for this reason (choice B). If lidocaine with epinephrine is used, you should keep the total amount given to a minimum. You should use 1:100,000, not 1:50,000 (choice A), because the 1:50,000 has twice as much epinephrine (it is more concentrated). List all antihypertensive medications in your chart (choice C) to be aware of any possible drug interactions with any medications you wish to use. Blood pressure is usually checked before invasive procedures (choice D), especially extractions. Non-emergency extractions are not done if blood pressure readings are too high.

Answer 64

D. ACETYLCYSTEINE: The medical treatment for acetaminophen overdose is acetylcysteine. The major toxicity of acetaminophen (Tylenol) is liver damage. Hepatocytes may be damaged by acetaminophen, and hepatitis and/or liver failure may result. Alternatives to treatment for acetaminophen toxicity include the administration of activated charcoal or, in worse cases, a liver transplant.

Answer 65

B. Drowsiness: as a sign of CNS depression, is associated with anesthetic effect but not with epinephrine. CNS depression from anesthetic occurs after initial CNS excitation. Therefore, nervousness and irritability (choice A) could be due to either early anesthetic effect or epinephrine effect. Tachycardia, or rapid heartbeat (choice C), and hypertension (choice D) are likely to be caused by epinephrine only. Bradycardia (reduced heartbeat) may be associated with anesthetic.

Answer 66

D. greater gastrointestinal absorption of amoxicillin: The current drug of choice for antibiotic premedication in the non-allergic patient is amoxicillin. The standard regimen is 2.0 grams amoxicillin P.O. 30 minutes to 1 hour before the procedure. The guidelines quoted here are from the 2017 American Heart Association revision. The guidelines are reviewed periodically, the prior review having occurred in 2007. Be aware that the guidelines may be revised again. Your school, textbook, clinic, or revisions to this course can bring you up to date should such changes occur. Prior to 1990, for example, penicillin VK was the drug of choice for the standard regimen. It was replaced by amoxicillin due to the more predictable gastrointestinal absorption of amoxicillin. Amoxicillin and penicillin both belong to the penicillin class of antibiotics and share similar incidence of allergic reactions. Amoxicillin, ampicillin, and penicillin V are equally effective in vitro against alpha-hemolytic streptococci. Note that penicillin G is not given orally. Penicillin V and amoxicillin both cause stomach irritation. The children's amoxicillin dose is 50 mg/kg.

Answer 67

D. OXACILLIN: Penicillinase-resistant penicillins are not attacked successfully by beta-lactamases. (Beta-lactamases are enzymes that create resistance to beta-lactam antibiotics, which includes penicillin.) They include: - Cloxacillin - Dicloxacillin - Oxacillin - Methicillin. - Nafcillin Note that most common penicillins are susceptible to penicillinases. In the case of amoxicillin, clavulanic acid may be added to reduce or prevent resistance. Clavulanic acid is a beta-lactamase inhibitor, which works by preventing bacteria from destroying the amoxicillin.

Answer 68

C. is a likely candidate for drug interactions: Competition between drugs for plasma protein binding sites can lead to drug interactions. Drugs with extensive plasma protein binding usually have low Vd (volume of distribution) values and slow renal elimination, because only the free fraction is filtered. Albumin is the major plasma protein to which drugs bind and the constant positive charge on quaternary amines prevents their binding to plasma proteins.

Answer 69

D. Procainamide: is a Class 1A antiarrhythmic used in the prevention of paroxysmal atrial fibrillation and tachycardia and is associated with the development of systemic lupus erythematous (SLE), which is an inflammatory autoimmune disorder that can affect multiple organ systems. Characteristic signs and symptoms of this disease can include fever, anorexia, malaise, malar rash (butterfly rash), photosensitivity, arthritis, serositis, and various hematologic and immunologic abnormalities. Medications associated with the development of SLE include: - Chlorpromazine - Hydralazine - Isoniazid - Methyldopa - Procainamide - Quinidine Cephalexin is a first-generation cephalosporin used in the treatment of a variety of skin and skin structure infections. This antibiotic has been associated with the development of hypersensitivity reactions, especially in penicillin-allergic patients. Chloramphenicol is a broad-spectrum antibiotic used in the treatment of many different infections. This agent is known to cause a disorder called "gray baby syndrome" when given to infants. Phenobarbital is an anticonvulsant used in the treatment of tonic-clonic seizures; it is associated with the development of agranulocytosis as well as other blood dyscrasias. Sulfamethoxazole/trimethoprim is a "sulfa" antibiotic used primarily in the treatment of urinary tract infections. This agent has been associated with the development of blood dyscrasias, especially in elderly patients and in those with some degree of immunosuppression.

Answer 70

D. They reversibly inactivate bacterial beta-lactamase activity: it's IRREVERSIBLY* Clavulanic acid is the beta-lactamase inhibitor that is added to amoxicillin (Augmentin® ). The beta-lactamase inhibitors are compounds added to antibiotics to help increase the effectiveness of the medication. The most common beta-lactamase inhibitors are clavulanic acid, sulbactam, and tazobactam. These compounds are weak antimicrobial agents. Beta-lactamase inhibitors irreversibly inactivate bacterial beta-lactamase enzyme, and dramatically improve the effectiveness of beta-lactamase-sensitive penicillin by preventing the inactivation of antibiotics sensitive to the enzyme beta-lactamase.

Answer 71

C. Diflunisal: is a fluorinated derivative of salicylate. This compound has potent anti-inflammatory and analgesic effects. Like aspirin, diflunisal inhibits cyclooxygenase and has similar pharmacologic effects to aspirin. However, unlike aspirin, this agent has little antipyretic effects. Aspirin: has more antipyretic effect than diflunisal Acetaminophen is an analgesic and antipyretic medication. Acetaminophen has no anti-inflammatory effects. Ibuprofen is an agent that possesses analgesic, anti-inflammatory, and antipyretic effects.

Answer 72

D. topical muciprocin: Impetigo is described as a type of superficial cellulitis primarily caused by group A streptococci. It is most commonly seen in hot, humid weather, which can aid in the colonization of the skin. When minor trauma occurs, such as a scratch, the bacteria enter the superficial layer of the skin, which subsequently results in the development of an infection. Furthermore, this is a highly communicable disease that can be spread through close contact. Patients with impetigo will present with small, fluid-filled (pus) vesicles that readily rupture and form the golden crusts that are characteristic of this disorder; pruritus is common. Muciprocin is a topical anti-infective agent produced by the fermentation of the organism Pseudomonas fluorescens. It inhibits bacterial protein synthesis by reversibly binding to bacterial isoleucyl-transfer RNA synthetase. Its spectrum of coverage includes aerobic isolates of S. aureus (including MRSA and beta-lactamase-producing strains), S. epidermidis, S. saprophyticus, and S.pyogenes and is indicated for the topical treatment of impetigo. - Clindamycin is an oral antibiotic indicated for the treatment of severe anaerobic infections when less toxic antibiotics are contraindicated. - Clobetasol is a topical corticosteroid indicated for the treatment of mild to moderate inflammatory conditions of the skin. - Erythromycin topical solution is a topical antibiotic indicated for the treatment of acne vulgaris. - Silver sulfadiazine is a topical preparation with a broad spectrum of antimicrobial activity; it is bactericidal for both gram-negative and gram-positive bacteria. It is indicated as an adjunct agent for the prevention and treatment of wound sepsis in patients with second- and third-degree burns.

Answer 73

A. First molar: The inferior alveolar nerve block is generally given to provide anesthesia for all mandibular extractions. It will anesthetize the nerves to all mandibular teeth on one side, the hard tissue on that side and most of the buccal soft tissue. The lingual nerve block, administered at the same time as the inferior alveolar nerve block, as the needle is removed, will anesthetize most of the soft tissue of the lingual side of the mandible, lingual gingiva and anterior two-thirds of the tongue. These two blocks should be sufficient for extraction of lower anterior teeth and first premolars. The first molar and sometimes the second premolar and second molar need additional anesthesia of the long buccal nerve, which innervates mucosa in the buccal area of the first molar.

Answer 74

D. Minocycline: Gentamicin is an antibiotic that is administered primarily by the IV route, not orally. Amoxicillin is a penicillin antibiotic and should not be used in patients with a penicillin allergy. Cephalexin is a first-generation cephalosporin that is closely related to the penicillins and therefore would not be a good choice. The remaining two choices are doxycycline and tetracycline, which are both tetracycline antibiotics. The tetracyclines are a class of antibiotics commonly used in the treatment of acne and various sexually transmitted disease as well as in the treatment of infections caused by susceptible organisms, such as Streptococcus pyogenes, in penicillin-allergic patients. Minocycline is a tetracycline that is excreted largely by non-renal routes. Its half-life and serum concentrations are not significantly increased in renal impairment. Hence, this medication would be the most recommended for this patient. Tetracycline is largely excreted in the urine and feces unchanged. Therefore, dosage adjustments need to be made in patients with renal impairment due to accumulation of the drug in the body.

Answer 75

D. it has anti-inflammatory properties: Pentazocin is a narcotic analgesic commonly used for the treatment of moderate to severe pain. This agent has similar properties to morphine; however, it has a longer duration of action. Like morphine, pentazocin has NO anti-inflammatory properties, can cause respiratory depression, and has analgesic properties. Pentazocin is primarily administered via the oral route. One of pentazocin's distinguishing factors is that it has partial narcotic antagonistic properties.

Answer 76

A. Ibuprofen: NSAIDs (i.e., Ibuprofen) have the potential to trigger heart failure through sodium and water retention, increased systemic vascular resistance, and blunted response to diuretics. Metoprolol is a beta-blocker and is used to treat patients with chronic heart failure. Captopril is an ACE inhibitor used in congestive heart failure patients to help prevent "ventricular remodeling" associated with this disease. Furosemide is a "loop" diuretic used to decrease the edema associated with congestive heart failure.

Answer 77

A. Calcium: Thiazide diuretics are commonly used in the treatment of various forms of edema and essential hypertension. One of the unlabeled uses of this medication is for the adjunctive treatment/prevention of osteoporosis in postmenopausal women with hypertension. Thiazides are effective in reducing the risk of osteoporosis because they decrease the elimination of calcium. Furthermore, thiazides are known to increase the elimination of chloride, magnesium, potassium, and sodium. Since potassium elimination can be substantial, individuals with hypokalemia should be advised to take this medication with food products high in potassium, such as bananas or orange juice.

Answer 78

A. Cardiac arrhythmias: Phenytoin is a common anticonvulsant used to treat most types of seizure disorders and status epilepticus, except absence seizures. Antidepressants typically inhibit the reuptake of norepinepherine and/or serotonin in the treatment of depression. Parkinson's disease is treated by with agents that are converted to dopamine or possess dopamine agonist properties. Potential risk factors for drug-induced gingival hyperplasia include the following: ``` Poor oral hygiene Periodontal disease Periodontal pocket depth Gingival inflammation Degree of dental plaque Duration and dose of medication ```

Answer 79

D. Large doses of sucralfate: Zollinger-Ellison syndrome is a disorder characterized by gastric acid hypersecretion and recurrent peptic ulceration. It is caused by a gastrinoma (gastrin-producing tumor), which leads to increased gastrin secretion and subsequent increased gastric acid secretion by the parietal cells. Patients often present with recurrent and severe peptic ulceration, typically accompanied by abdominal pain, bleeding, and/or perforation. The most optimal treatment measure is surgical resection. This, however, may not be possible due to individual patient characteristics. The first-line therapy for this condition is large doses of the proton-pump inhibitors, such as omeprazole and lansoperazole. Other agents that can effectively inhibit gastric acid secretion are large doses of H2-receptor antagonists, such as cimetidine, famotidine, and ranitidine. Large doses of sucralfate would be inappropriate in this patient, since the agent is primarily used as an intestinal tract protectant and does not decrease the production of gastric acid. Octreotide is an agent that decreases acid secretion through the reduction of serum gastrin levels and by directly inhibiting the action of the parietal cells.

Answer 80

A. Activated partial thromboplastin time: Heparin is administered to individuals with acute embolism or thrombosis by continuous intravenous infusion at a rate sufficient enough to raise the activated partial thromboplastin time (aPTT) to 1.5 to 2 times the control value. In other words, the anticoagulant effect of heparin is monitored by the aPTT. The aPTT is continually monitored to ensure that the patient does not exceed 1.5 to 2 times the control value. As the control aPTT value is continually exceeded, the risk for "internal bleeding" increases. The bleeding time is a measure of platelet function and correlates well with the propensity to bleed. A complete blood count, or CBC, is a measure of all the "cell components" contained in the blood, such as number of white blood cells, red blood cells, platelets, etc. Both the international normalized ratio (INR) and prothrombin time (PT) are used to monitor the anticoagulant effect of coumarin anticoagulants, such as warfarin. Coumarin anticoagulants are dosed to raise the prothrombin time to 1.5 to 3.5 times the control value. However, the thomboplastins used in the monitoring of PT values vary between institutions, leading to different control values and subsequently different levels of anticoagulation for a given patient. In other words, there is no absolute consistency for a PT value taken at two different hospitals. Therefore, INR values are commonly used because the INR at one institution will "equal" that of another.

Answer 81

C. Captopril: Angioedema is a well-demarcated, localized edema involving the deeper layers of the skin, including the subcutaneous tissue. This condition is seen with ACE inhibitors, particularly CAPTOPRIL, ENALAPRIL, and LISINOPRIL. Atenolol is a beta-1-selective receptor-blocking agent that is associated with the development of bradycardia, dizziness, and impotence in men. Verapamil is a calcium channel blocker that possesses strong negative inotropic effects and can cause hypotension and dizziness. Indapamide is a thiazide diuretic that is known to cause glucose intolerance in diabetics, electrolyte abnormalities, and photosensitivity. Treatments with Beta-blockers, Calcium channel blockers, and thiazides have also caused angioedema, but it is most frequently seen with ACE inhibitors.

Answer 82

D. Ciprofloxacin: prevents DNA synthesis through its action on DNA gyrase enzyme. Clotrimazole: is an antifungal of the imidazole family and interferes with ergosterol synthesis in cell membranes. Chloramphenicol: is a synthetic antibiotic acting on the 50S subunit of the bacterial ribosome. Cloxacillin: inhibits bacterial cell-wall synthesis.

Answer 83

E. Botanical: By definition, a botanical is a compound or extract derived from a plant. A drug is a substance that is intended for use in the diagnosis, cure, mitigation, treatment, or prevention of a given disease. A poison is a chemical that kills or inhibits the growth of a living organism. A toxin can be defined as a harmful substance produced by a living organism. A xenoantigen is an antigen occurring in organisms of more than one species.

Answer 84

E. Clindamycin: Antibiotics with particular effectiveness against ANAEROBES include: - Second-generation Cephalosporins - Clindamycin - Metronidazole Streptomycin: specifically, is active only against AEROBES.

Answer 85

D. Lidocaine: Arrhythmias following myocardial infarct are best managed by administering IV lidocaine because it acts on the ventricular muscle. - Adenosine: indicated for SVTs and nodal tachycardia. - Diltiazem(CCBs): AV node - Esmolol(beta blocker): AV node Neither of these is very effective in the treatment of ventricular arrhythmias.

Answer 86

D. Erythromycin: Cellulitis is often described as an acute infection initially involving the epidermis and dermis. As the infection progresses, the superficial fascia may also become involved; inflammation in and around the affected area is common. These infections are generally caused by a disruption of the normal host defenses, such as a puncture of skin or introduction of foreign body into the skin. Cellulitis can be caused by the bacteria that normally colonize the skin, such as Staphylococci (especially coagulase-negative strains), Streptococci, Diphtheroids (such as Corynebacterium), and Propionibacteria. The patient is noted to have a past medical history significant for an anaphylactic reaction to penicillin; therefore, the most recommended oral medication would be erythromycin. Erythromycin is a macrolide antibiotic unrelated to the penicillins. It is indicated for the treatment of numerous infections caused by gram-positive organisms, including streptococcal cellulitis, as well as a variety of infections caused by gram-negative organisms. Amoxicillin is a penicillin antibiotic and therefore should not be administered to this patient due to risk of developing an anaphylactic reaction. Cephalexin is a cephalosporin antibiotic often considered to be the drug of choice for the treatment of a gram-positive cellulitis. However, there is a 5% to 15% chance that this patient will be allergic to this medication since it is structurally related to the penicillins. Clindamycin is an antibiotic primarily indicated for the treatment of infections caused by anaerobic organisms when less toxic alternatives are not available. Vancomycin is indicated for the treatment of primarily gram-positive infections, this medication is administered primarily via the intravenous route, not the oral route. Furthermore, this medication is generally reserved for serious life-threatening infections, not a mild case of cellulitis.

Answer 87

B. Indomethacin: All of the listed medications are nonsteroidal anti-inflammatory drugs (NSAIDs) with the usual properties of being analgesic, anti-inflammatory, and antipyretic, except diflunisal, which is not antipyretic. Indomethacin, in addition to the above uses, is taken to help close patent ductus arteriosus (a hole connecting the pulmonary artery and aorta, which normally closes around the time of birth). This is achieved by inhibiting prostaglandin synthesis, which results in constriction of the ductus arteriosus. In addition to pain, naproxen sodium can be used for migraines. Flurbiprofen is often used for osteoarthritic pain, but off-label uses include management of dental postoperative pain.

Answer 88

B. Cyclophosphamide: Chemotherapeutic agents include a wide range of compounds that work by many different mechanisms. Although these medications are designed to selectively destroy neoplastic tissue, the agents currently available manifest significant toxicity on many different non-neoplastic tissues. The "nitrogen mustard" antineoplastics are a sub-group of agents contained in the larger category of alkylating agents. - Cyclophosphamide is considered to be a nitrogen mustard. Cisplatin: is an alkylating agent, it is not considered a nitrogen mustard. Doxorubicin is classified as an anthracycline antibiotic. Methotrexate is an antimetabolite used in the treatment of various types of cancer. Furthermore, methotrexate is commonly used in the treatment of rheumatoid arthritis. Vincristine is classified as a mitotic inhibitor.

Answer 89

B. Clonidine: All of the agents in this question can be used in the treatment of hypertension. Clonidine, Methyldopa, Guanabenz: centrally acting sympatholytic agents that decrease the sympathetic outflow by stimulating central alpha-2-adrenergic receptors. Atenolol is a peripheral adrenergic beta-1-specific blocking agent. Guanethidine and reserpine are adrenergic neuron blockers that reduce the amount of circulating catecholamines. Hydralazine is a direct vasodilator that relaxes vascular smooth muscle and induces vasodilation.

Answer 90

C. Doxorubicin: Chemotherapeutic agents include a wide range of compounds that exert their antineoplastic effects by a variety of different mechanisms. Although these medications are designed to selectively destroy neoplastic tissue, the agents currently available manifest significant toxicity on many different non-neoplastic tissues. Doxorubicin is an anthracycline antibiotic. This agent is used in the treatment of acute leukemias, breast carcinoma, and Hodgkin and non-Hodgkin lymphoma as well as many other forms of cancer. The "nitrogen mustard" antineoplastics are a subgroup of agents contained in the larger category of alkylating agents. Cyclophosphamide is considered to be a nitrogen mustard. Cisplastin is an alkylating agent. Methotrexate is an antimetabolite used in the treatment of various types of cancer and rheumatoid arthritis. Vincristine is classified as a mitotic inhibitor.

Answer 91

E. Vancomycin: Pseudomembranous colitis is caused by a necrolytic toxin produced by Clostridium difficile, which, under specific circumstances, is able to proliferate in the bowel. Pseudomembranous colitis most commonly occurs secondary to the usage of antibiotics that disrupt the normal bowel flora, permitting C. difficile to proliferate. Almost all antibiotics can cause this disorder, which results in profuse watery/bloody diarrhea. The most effective treatment for pseudomembranous colitis is: - Vancomycin* - Metronidazole and Bacitracin have been used effectively to treat this disorder. Although pseudomembranous colitis causes profuse diarrhea, the use of antidiarrheal agents, such as attapulgite and loperamide, is contraindicated. Clindamycin is a bacteriostatic antibiotic used primarily in the treatment of many different anaerobic infections. This antibiotic is one of the primary agents implicated in the development of pseudomembranous colitis. Although sulfasalazine is indicated in the treatment of ulcerative colitis, it is ineffective in the treatment of pseudomembranous colitis.

Answer 92

E. Prochlorperazine: Extrapyramidal signs and symptoms, such as pseudoparkinsonism, are commonly seen in patients receiving medications that block the dopamine receptor. Pseudoparkinsonism, as the name implies, is a condition in which patients experience signs and symptoms similar to the symptomatology associated with Parkinson disease. These symptoms include mask-like facies, drooling, tremors, pill-rolling motion, cogwheel rigidity, and shuffling gait. Pseudoparkinsonism symptoms are commonly seen in individuals taking antipsychotic medications and other phenothiazines such as prochlorperazine. Calcium carbonate is an antacid. Dimenhydrinate is an antihistamine commonly used in the treatment of motion sickness. Dronabinol is a narcotic used in the treatment of severe nausea and vomiting; this agent is the psychoactive substance found in marijuana. Ondansetron is a 5-HT3-receptor blocking agent and is used in the treatment of severe nausea and vomiting, especially in patients receiving emetogenic cancer chemotherapy.

Answer 93

C. Mexiletine: Lidocaine and Mexiletine are classified as Class 1B antiarrhythmic agents that shorten the action potential duration and refractory period and improve the resting potential duration. They produce a modest suppression of sinus node automaticity as well as AV node conduction. Esmolol is a Class II antiarrhythmic agent that exerts its action as an ultra-short-acting beta-1-adrenergic blocking agent with cardioselective properties. Disopyramide and quinidine are Class 1A antiarrhythmics. They depress myocardial excitability, conduction velocity, contractility, and automaticity. These agents also prolong the effective refractory period and block vagal stimulation of the AV node. Verapamil is a calcium-channel blocking agent and a Class IV antiarrhythmic agent that decreases and slows SA and AV node conduction. Anti-arrhythmics • Class I: Na channel blockers (NCBs) o IA: (ADPQ) depress myocardial excitability, conduction velocity, contractility, automaticity, prolong effective refractory period & block vagal stimulation of AV node ♣ Amiodarone(cordarone) ♣ Disopyramide(norpace) = prolong AP ♣ Procainamide(procan sr): side- SLE ♣ Quinidine(quinidex): side- SLE o IB: (LMT) shorten AP ♣ Lidocaine(xylocaine) ♣ Mexiletine(mexitil) ♣ Tocainide(tonocard) o IC: Flecainide(tambocor), Propafenone(rhythmol) = no AP effect • Class II: ultra-short acting beta1-adrenergic blocking agents w/ cardioselective properties; increase refractory period, decrease conduction velocity, reduce automaticity o Acetbutolol(sectral) o Esmolol(brevibloc) o Metoprolol(Lopressor): o Propranolol(Inderal) • Class III: K+ channel blockers (KCBs) o Amiodarone(cordarone), Sotalol(betapace), Ibutilide(corvert), Dofetilide(tikosyn) = increase refractory period, reduce automaticity • Class IV: CCBs – indirect vasodilators (Diltiazem, Nifedipine, Verapamil), antiarrhythmic agent- decreases & slows SA&AV node conduction o Verapamil(calan), Diltiazem = increase refractory period, decrease conduction velocity & automaticity ♣ Verapamil: strong negative ionotropic, side- hypotension & dizziness

Answer 94

B. Antipyrine: The agents listed in this question are used primarily in the treatment of otitis media or cerumen impaction. Antipyrine is commonly added to otic preparations due to its analgesic properties. - Aluminum acetate is often added to an acetic acid and boric acid solution to make "Burrow's" solution. This solution possesses antibacterial and antifungal properties. - Carbamide peroxide is an earwax emulsifier commonly found in earwax removal products. - Neomycin is an aminoglycoside antibiotic used for the treatment of bacterial otitis media.

Answer 95

B. Inhibition of bacterial cell wall synthesis: Cephalexin is a first generation cephalosporin commonly used to treat skin infections as well as infections caused by susceptible pathogens in the respiratory and urinary tracts, middle ear and bone. Cephalosporins, such as cephalexin, are believed to exert their antibacterial effect through the inhibition of bacterial cell wall synthesis. These agents bind to one or more of the penicillin-binding proteins located on the cell walls of susceptible organisms. This action results in the inhibition of the third and final stage of bacterial cell wall synthesis. This effect accounts for the bactericidal effect of cephalosporins and their "cousins": the penicillins. Sulfonamide antibiotics exert their antibacterial effect through the competitive inhibition of para amino-benzoic acid (PABA), thereby inhibiting folic acid biosynthesis required for bacterial growth. Quinolone antibiotics inhibit DNA-gyrase, which is an enzyme necessary for bacterial DNA replication and repair. Aminoglycosides, such as gentamicin, irreversibly bind to the 30s subunit of bacterial ribosomes, which inhibits bacterial protein synthesis. Lincosamides, such as clindamycin, irreversibly bind to the 50s subunit of bacterial ribosomes, which suppresses bacterial protein synthesis. Macrolides, such as erythromycin, reversibly bind to the 50s subunit of bacterial ribosomes, which suppresses bacterial protein synthesis.

Answer 96

C. Ceftazidime: Pseudomonas aeruginosa pneumonia is a very serious infection. This organism is associated with a relatively high rate of morbidity and mortality when improperly treated. Furthermore, Pseudomonas is resistant to most antibiotics. However, selected 3rd-generation Cephalosporins such as Ceftazidime, extended spectrum penicillins, and some fluoroquinolones have good activity against this organism. Of the agents listed, only Ceftazidime is effective in the treatment of Pseudomonas. Ampicillin is a penicillin antibiotic used primarily in the treatment of urinary tract infections and some upper respiratory tract infections. Cefixime is a third-generation cephalosporin with excellent gram-negative coverage; however, this agent is ineffective in the treatment of Pseudomonas infections. Sulfamethoxazole/trimethoprim is a "sulfa" antibiotic used primarily in the treatment of urinary tract infections and some upper respiratory tract infections. Vancomycin is an intravenous antibiotic generally reserved for the treatment of resistant gram-positive organisms.

Answer 97

B. Pulmonary congestion: Morphine continues to be used in pulmonary congestion, partly because of its sedative and analgesic effects and also because of its vasodilating action, which results in favorable hemodynamics in terms of cardiac and pulmonary function. Similarly, morphine is of value in an acute myocardial infarction -- especially its ability to relieve pain. Morphine is not suitable for pain of biliary origin because it causes contraction of the sphincters of Oddi, leading to spasms. Serotonergic antidepressants are used to treat generalized anxiety disorders; codeine is prescribed for the treatment of cough; and benzodiazepines and baclofen are used to treat and suppress alcohol withdrawal syndrome, respectively.

Answer 98

B. Azithromycin: Bacteriostatic antibiotics inhibit or retard the growth of microorganisms. Azithromycin is a macrolide antibiotic with bacteriostatic properties. Penicillin and Cephalosporins are bactericidal antibiotics. By definition, bactericidal antibiotics cause the death of the bacteria. Ciprofloxacin, a fluoroquinolone, exhibits a bacteriostatic activity when the replication of DNA is inhibited by inhibiting DNA gyrase and a bactericidal activity caused by bacterial DNA fragmentation.

Answer 99

B. Ampicillin: If the patient is not penicillin allergic, but cannot swallow the oral medication for some reason, the substitution is to give the medication IV or IM. The drug of choice in this case is ampicillin. It is given as 2.0 grams IV or 1M, 30 minutes to 1 hour prior to the procedure. The children's dose is 50 mg/kg. Penicillin VK, Amoxicillin, Azithromycin, and Clindamycin would not be administered in this manner. Refer to your home study notes for a complete list of approved antibiotics.

Answer 100

D. Latanoprost: is a prostaglandin F2-alpha analog that is believed to reduce intraocular pressure (IOP) by increasing the outflow of aqueous humor. This agent is indicated for lowering IOP in patients with open-angle glaucoma and ocular hypertension who are intolerant to other agents. Acetazolamide is an oral agent that inhibits the enzyme carbonic anhydrase, which leads to a reduction in the production of aqueous humor. Brimonidine is an alpha-2 adrenergic receptor agonist that has peak ocular hypotensive effects at 2 hours post-dosing. Carbachol is a parasympathomimetic agent that lowers IOP in patients with glaucoma. Levobunolol is a beta-adrenergic-receptor antagonist that has peak ocular hypotensive effects at 1 to 2 hours post-dosing. This agent decreases IOP with little or no effect on pupil size or accommodation.

Answer 101

B. Cortisone: The glucocorticoids are indicated for the treatment of a variety of allergic, anti-inflammatory, and hormonally related conditions. When prescribing these products, it is important for the clinician to know the relative potencies of each of these agents as well as an approximate equivalent dosage. The following is a summary of the approximate equivalent doses and anti-inflammatory potencies: In summary, the relative anti-inflammatory potencies of the agents listed are as follows: - Dexamethasone - Methylprednisolone - Prednisone - Hydrocortisone - Cortisone

Answer 102

A. Inhalation: The most important part of this question is the word "absorption." Intravenous introduction of a drug does not involve absorption because the drug is injected directly into the circulation; therefore, this cannot be the correct answer. All of the remaining choices are modes that are associated with absorption. However, the inhalation mode is the most rapid because of the great area of the absorptive surface and the close proximity of the blood.

Answer 103

C. Tetralogy of Fallot: According to the 2017 American Heart Association guidelines, antibiotic prophylaxis ahead of dental procedures is reasonable for patients with cardiac conditions associated with the highest risk of adverse outcomes from endocarditis, including: - Prosthetic cardiac valves (including homografts and transcatheter-implanted prostheses) - Prosthetic material used for cardiac valve repair (including annuloplasty rings and chords) - History of infective endocarditis - Unrepaired cyanotic congenital heart disease or repaired congenital heart disease with residual shunts or valvular regurgitation at, or adjacent to, the site of a prosthetic patch or prosthetic device - Cardiac transplant with valvular regurgitation (attributed to a structurally abnormal valve) ``` Antibiotic prophylaxis for preventing subacute bacterial endocarditis in dental patients is NOT recommended with the following conditions: Atrial septal defects Ventricular septal defects Patent ductus arteriosus Mitral valve prolapse History of Kawasaki disease Hypertrophic cardiomyopathy Previous coronary artery bypass graft surgery Cardiac pacemakers (intravascular, epicardial) and implanted defibrillators Bicuspid aortic valves Coarctation of the aorta Calcified aortic stenosis Pulmonic stenosis ``` Please note: Tetralogy of Fallot is characterized by the following: - Right ventricular hypertrophy (RVH) - Overriding aorta - Ventricular septal defect (VSD) - Pulmonary valve stenosis - Patients with unrepaired tetralogy of Fallot are usually cyanotic ("blue"). Tetralogy of Fallot is treated surgically. In small infants, a preliminary surgery is performed, in which a small tube of synthetic material is placed between the aorta and the pulmonary artery. Complete repair is usually performed early in life. The VSD is closed with a patch. To address the RVH, the right ventricular outflow tract is opened up by removing a portion of the hypertrophied muscle below the pulmonary valve, repairing or removing the obstructed pulmonary valve, and if needed, enlarging the branch pulmonary arteries that go to each lung. Sometimes a tube is placed between the right ventricle and the pulmonary artery. Children with tetralogy of Fallot are at an increased risk for endocarditis, as they may have a valve replacement, a residual shunt, or leaks around surgical patches. Hence, antibiotic prophylaxis before certain dental procedures is recommended in order to help prevent endocarditis.

Answer 104

E. Theophylline: Respiratory alkalosis is a disorder that results from tachypnea and hyperpnea leading to decreased carbon dioxide blood levels. This condition is caused by agents that stimulate the central nervous system. Agents most commonly associated with respiratory alkalosis include amphetamines and the xanthine derivatives, such as theophylline and caffeine. Alprazolam is a benzodiazepine associated with the development of respiratory depression. Metabolic alkalosis is caused by an overproduction of bicarbonate leading to an increased arterial pH. Metabolic alkalosis can be caused by chloruresis and volume depletion secondary to diuretic usage. Examples of diuretics include furosemide and hydrochlorothiazide. Morphine and oxycodone are opiate analgesics used for the treatment of moderate to severe pain. These agents can cause respiratory depression, especially in an overdose situation. This respiratory depression results in hypoventilation, leading to carbon dioxide retention and respiratory acidosis. The respiratory acidosis then causes an increased production of bicarbonate to compensate for the decreased arterial pH.

Answer 105

E. cannot be well predicted: Bacterial endocarditis is highly unpredictable. Two patients with similar heart conditions and similar oral hygiene may undergo similar dental procedures. One of these patients may develop endocarditis, while the other does not. The type of dental procedure (choice A), the endocarditis history of the patient (choice B), the severity of the defect (choice C), and the level of plaque (choice D) are all reasonable factors, which may affect the chances of endocarditis developing. In spite of this fact, it is still highly unpredictable. Many unknown host factors may be involved.

Answer 106

C. Cefadroxil: Azithromycin, Clindamycin, and Clarithromycin are valid alternatives to penicillin in patients allergic to it. As per 2017 AHA guidelines: Azithromycin (500 mg orally, 30 minutes to 1 hour prior to the dental procedure), Clarithromycin (500 mg, 30 minutes to 1 hour prior to the dental procedure) or Clindamycin (600 mg, 30 minutes to 1 hour prior to the dental procedure) are recommended for antibiotic prophylaxis for infective endocarditis in patients allergic to penicillin. Earlier it was believed that approximately 10% of patients with a history of penicillin allergy will also have an allergic reaction to Cephalosporin. However, it is now reported that the overall cross-reactivity rate is approximately 1% with first-generation Cephalosporins (e.g., Cefadroxil: choice C) or cephalosporins with similar R1 side chains. Please note: Cross-allergy with penicillins is reported with first-generation cephalosporins; however, cross-allergy is negligible with second- and third-generation cephalosporins.

Answer 107

D. Drowsiness: Irritability can be due either to the CNS stimulation of epinephrine or the depression of inhibitory neurons by local anesthetic. Rapid breathing is most likely caused by a CNS effect of epinephrine. Tachycardia or increased heart rate is most likely due to cardiac effects of epinephrine. Local anesthetics are generally cardiac depressants causing bradycardia. Drowsiness is likely to be caused by local anesthetic alone, as anesthetic generally affects inhibitory neurons first, causing CNS stimulation, then all neurons later, causing CNS depression. Epinephrine will not cause CNS depression. So, drowsiness is a local anesthetic effect only. Both epinephrine and the local anesthetic can cause nervousness.

Answer 108

D. Weight of patient: The child's age (choice A) is not used to determine the maximum dose of local anesthesia because same-aged children can vary in size. The procedure to be accomplished (choice B) or the length of time to complete the procedure (choice C) also do not determine the maximum dose because neither one indicates whether the amount administered is toxic. Dosage is determined and adjusted by the weight of the patient (choice D).

Answer 109

B. Phenobarbital: Diuresis and ion trapping via alteration of urine pH may help to prevent the reabsorption of various compounds in the kidneys. Membranes are more permeable to nonionized molecules than to the ionized form of the same drug. Therefore, acidic compounds are ionized, trapped, and excreted in an alkaline urine and basic compounds are ionized, trapped, and excreted in an acidic urine. Alkaline diuresis (with a urine pH greater than 7.5) enhances the elimination of drugs that are "acidic" by nature, such as phenobarbital and salicylates. Acidic diuresis enhances the elimination of "basic" medications, such as cocaine, sympathomimetic amines such as phentermine, phenylpropanolamine, phencyclidine, quinidine, and strychnine. If sodium bicarbonate was administered in an overdose situation in which a "basic" medication was ingested, the elimination of this medication would be decreased, and toxicity would be enhanced. The elimination of sodium hypochlorite, otherwise known as laundry bleach, would not be enhanced by the administration of sodium bicarbonate. Bleach is a very "basic" substance that is irritating to the mucosa of the intestinal tract. Treatment of toxicity generally consists of dilution or gastric lavage for larger ingestions.

Answer 110

C. Lidocaine: The Food and Drug Administration (FDA) has established a set of pregnancy categories A, B, C, D, and X to determine the rational use of any medication that requires a risk versus benefit assessment. The higher the category, the safer the drug is for pregnancy. Regardless of the designated pregnancy category or presumed safety, no medication/drug should be administered during pregnancy unless it is clearly needed and the potential benefits outweigh the potential hazards to the fetus. Lidocaine is included in pregnancy category B, which is considered safer than category C, the category of the other anesthetics listed.

Answer 111

E. Metronidazole: Pseudomembranous colitis is caused by the necrolytic toxin produced by Clostridium difficile. Pseudomembranous colitis most commonly occurs secondary to the usage of antibiotics that disrupt the normal bowel flora and permit other bacteria to proliferate. Almost all antibiotics can cause this disorder, which results in profuse watery, bloody diarrhea. The alternative name for this condition is AAC (antibiotic-associated colitis). The two most effective treatments for pseudomembranous colitis are: - Metronidazole - Vancomycin. Furthermore, bacitracin has also been used effectively to treat this disorder. Although pseudomembranous colitis causes profuse diarrhea, the use of antidiarrheal agents, such as altapulgite and diphenoxylate/atropine, are contraindicated. Clindamycin is a bacteriostatic antibiotic used primarily in the treatment of many different anaerobic infections. This antibiotic is one of the primary agents implicated in the development of pseudomembranous colitis. Although mesalamine is indicated in the treatment of ulcerative colitis, it is ineffective in the treatment of pseudomembranous colitis.

Answer 112

A. Cholestyramine: The bile acid-binding sequestrants, such as cholestyramine, lower plasma LDL levels approximately 20% at normal doses. However, triglyceride and VLDL concentrations will initially rise by 5% to 30% and return to baseline levels after approximately 1 month of therapy. Both Fenofibrate and Gemfibrozil are fibric acid derivatives used primarily to decrease triglyceride levels. Niacin is used to decrease both triglyceride and LDL levels. Simvastatin is an HMG-CoA reductase inhibitor that is also used to decrease both LDL and triglyceride levels.

Answer 113

A. Albuterol: Although albuterol is used primarily via inhalation for treating asthma, its systemic effects include vasodilation due to its β 2 receptor activation. This can result in a decrease in PVR and mean BP, which elicits a reflex tachycardia. Methoxamine and Phenylephrine are α -receptor activators causing vasoconstriction, which would result in reflex bradycardia. Ganglion blockers (e.g., mecamylamine) prevent autonomic reflexes, and a reflex increase in heart rate could not occur in the presence of a beta-blocker (e.g., propranolol).

Answer 114

C. Intravenously: Shock is a life-threatening condition characterized by circulatory system failure where the patient's circulatory system is unable to adequately perfuse the body's vital organs. Therefore, vasopressor medications need to be administered to increase the blood pressure so that these organs will receive adequate blood supply. In shock, vasopressor medications should be administered via the intravenous route (choice C) for the following reasons: This route allows for "immediate" delivery to the target organs 100% of the medication administered is delivered Dosage changes can be made very quickly Since all of the other routes of administration cannot provide these pharmacokinetic benefits, they should not be used to administer medication to a patient with shock. In the intramuscular route (choice A) medication is injected into a muscle, as the name implies. Intrathecal administration (choice B) provides medication to the central nervous system. Although all of the pharmacokinetic parameters with this route of administration are the same as the intravenous route, intrathecal administration would not be used in a patient with shock since the target organs are in the circulatory system, not the central nervous system. In the oral route (choice D), the medication must pass through the intestinal tract and be absorbed, which can take several hours to occur; treatment of shock needs to be immediate. Subcutaneous administration (choice E) involves the injection of medication into the subcutaneous layer of the dermis; this is the ideal route of administration for insulin because this route is able to provide a "sustained" release of medication into the systemic circulation.

Answer 115

B. Ketamine: is a rapid-acting general anesthetic that produces an anesthetic state characterized by profound analgesia and a dissociative type of anesthesia. The dissociative anesthesia is produced by an interruption of the association pathways of the brain before producing somesthetic sensory blockade. One of the psychological manifestations of ketamine is that many patients experience dream-like states, vivid imagery, hallucinations, and emergence delirium. Halothane (choice A) is an inhalation anesthetic associated with anesthesia and skeletal muscle relaxation. Nitrous oxide (choice C) is an inhalation anesthetic typically used in combination with other agents, since it fails to induce anesthesia in greater than 50% of all patients. It does not produce analgesia. Propofol (choice D) is a "newer" general anesthetic used in the induction and/or maintenance of anesthesia; it does not produce analgesia. Thiopental (choice E) is an ultra-short-acting barbiturate that induces anesthesia without analgesia.

Answer 116

B. Chlorpromazine: Pseudoparkinsonism symptoms -- as the name implies -- are similar to the symptomatology associated with Parkinson's disease, and include mask-like facies, drooling, tremors, pill-rolling motion, cogwheel rigidity, and shuffling gait. Pseudoparkinsonism symptoms are commonly seen in individuals taking antipsychotic medications, particularly phenothiazine derivatives such as chlorpromazine. Phenothiazines are dopamine receptor antagonists. Since Parkinson's disease is believed to be caused by a deficiency of dopamine, a dopamine receptor blocking agent would be able to cause a variety of Parkinson-like effects. None of the other answer choices are associated with the development of these symptoms. Pseudoparkinsonism symptoms can be effectively controlled by using anti-Parkinson's medications, such as benztropine. Benztropine is a centrally acting anticholinergic agent used in the symptomatic treatment of all forms of Parkinsonism and to relieve the extrapyramidal symptoms associated with antipsychotic usage. Lorazepam is a benzodiazepine used in the management of anxiety disorders. Phenobarbital is a long-acting barbiturate used in the management of tonic-clonic seizures. Phenytoin is a hydantoin derivative used to control tonic-clonic, psychomotor, and nonepileptic seizures.

Answer 117

E. Erythromycin: is known for being associated with gastric disturbances and thus unreliable absorption. It was removed from the subacute bacterial endocarditis prophylaxis list by the American Heart Association. The list of recommended antibiotics includes amoxicillin, ampicillin, clarithromycin (choice A), clindamycin (choice B), azithromycin (choice C), cephalexin, cefadroxil (choice D), and cefazolin.

Answer 118

B. Decreased glucose tolerance: Hydrochlorothiazide is a diuretic commonly used in the treatment of hypertension and edema associated with congestive heart failure. Hydrochlorothiazide is known to increase fasting blood glucose, especially in diabetic patients. In other words, this medication decreases glucose tolerance. In diabetic patients, it may be necessary to make dosage adjustments of both oral hypoglycemic agents and/or insulin to maintain euglycemia, when taken concomitantly with this medication. Hydrochlorothiazide is associated with increased blood levels of uric acid (choice A), increased total cholesterol blood levels (choice C), hypokalemia (choice D), and hyponatremia (choice E).

Answer 119

C. 13: Using the information given above and knowing that the maximum dose of lidocaine is 7 mg/kg as well as that the volume of a carpule is 1.8mL, we can arrive at the suggested maximum number of carpules as 13.61. We are rounding down because it would be impractical to push the limits to try and administer .61 of a carpule. It only makes good clinical sense to set the maximum number of carpules at 13. The calculations are performed below: 7 mg/kg (known max dose) * 70 kg patient = 490 mg of lidocaine for a maximum dose From here, we need to figure out how many mg of lidocaine are in a single carpule: 2% lidocaine * 1.8mL = 36mg of lidocaine per carpule 490 mg of lidocaine maximum dose / 36 mg of lidocaine per carpule = 13.61 carpules

Answer 120

D. Estradiol (estrogen): A lower level of estrogen causes paucity of saliva leading to xerostomia, burning mouth syndrome, increase in incidence of dental caries, dysesthesia, taste alterations, atrophic gingivitis, periodontitis, and osteoporotic jaws. Xerostomia is a condition associated with a dryness of the mouth resulting from diminished or arrested secretion. Several drugs cause xerostomia including anticholinergics, antidepressants, antihistamines, antihypertensive agents, antiparkinsonian drugs, antimigraines, antineoplastic drugs, antipsychotics, antiseizures, cytotoxic agents, diuretics, muscle relaxants, sedatives, and anxiolytics. Other drugs causing xerostomia include appetite suppressants, supplements, nonsteroidal anti-inflammatory drugs (NSAIDs), systemic retinoids, antiretroviral drugs, and medications like cytokines (interferon-alfa, interleukin 2). Xerostomia leads to taste alterations, dysphagia, speech disturbance, and dental caries.

Answer 121

D. Solution: Bioavailability is defined as the physiologic availability of a given amount of drug, as distinct from its chemical potency. In other words, bioavailability is the amount of drug that reaches systemic circulation in relation to the original amount administered. The rate at which drugs become bioavailable is dependent upon the following: the rate of disintegration of the drug from a solid dosage form, the rate of dissolution of the drug, and the rate of absorption from the intestinal tract. A solid dosage form must be disintegrated into fine granules or aggregates. These fine particles must undergo dissolution (i.e., the drug must be in the form of a "solution" before it can be absorbed). Therefore, a medication that is already in a solution formulation will yield the most rapid rate of drug bioavailability. Controlled-release tablets are designed to provide a "constant" amount of drug over a sustained period of time. Medication in a controlled-release tablet formulation will yield the slowest rate of drug bioavailability. Both gelatin capsules and immediate-release tablet formulations must be dissolved into granules and then into solution before they can be absorbed. Suspensions contain small granules of drug suspended in a medium. These drug granules must still undergo dissolution before they can be absorbed.

Answer 122

B. 600mg: Oral clindamycin is given to children at 20 mg/kg, with the total dose not to exceed the adult dose. In this question, 20 mg/kg is multiplied by 50 kg to give 1,000 mg or 1.0 gram. However, this would exceed the adult dose (600 mg), so only 600 mg is given.

Answer 123

C. Cyclooxygenase-2 (COX-2): Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the biosynthesis of hyperalgesic and proinflammatory prostaglandins. These agents exhibit antipyretic, anti-inflammatory, and mild analgesic properties. When arachidonic acid is acted upon by the enzyme cyclooxygenase (COX), prostaglandins are formed. There are two forms of COX: COX-1 and COX-2. COX-2 is responsible for generating the prostaglandins at the site of inflammatory and/or tissue damage. COX-1 is responsible for producing the "good" prostaglandins that maintain blood flow through organs and protect the intestinal mucosa. Adenylyl cyclase (AC) is the enzyme inhibited by opioid analgesics. When AC is inhibited, cAMP levels fall, which leads to an analgesic effect. Nitrous oxide (N2O) is a hypnotic agent used in dentistry as an adjunct to anesthesia. Thromboxane A2 (TXA2) is a vasoconstricting and proaggregatory compound commonly associated with platelets.

Answer 124

B. Metoclopramide: Oral products and medications must be carefully administered to a patient with a partial bowel obstruction because of the risk of worsening the bowel obstruction. As a general rule, the administration of any product that stimulates the intestinal tract is contraindicated in patients with any degree of bowel obstruction. These products can actually promote an intestinal tract perforation secondary to the build-up of pressure behind the obstruction. Since metoclopramide is a prokinetic agent that stimulates the intestinal tract, the use of this agent is absolutely contraindicated in patients with partial bowel obstruction. Antacids may be acceptable for usage in these patients; however, the clinician must keep in mind that certain antacids can cause constipation and may worsen the degree of obstruction. The use of agents that suppress acid secretion, such as omeprazole and ranitidine, is considered safe.

Answer 125

A. anesthetic hydrochloride to free base: The anesthetic hydrochloride injected into tissue must be neutralized by tissue buffers to form the un-ionized free base. This non-polar form can easily diffuse through the lipid membrane of the axon. Infected tissue generally has a low pH, that is, it is acidic. In this case, the acidic ionized hydrochloride form will not form free base, will not enter the neuron cell membrane, and then will not block sodium channels. Free base to anesthetic hydrochloride does not occur and is opposite to the normal sequence. Free base to ionized form occurs once free base enters the neuron. Anesthetic hydrochloride to ionized form is incorrect because the hydrochloride form is already ionized.

Answer 126

D. Ofloxacin: The patient is most likely experiencing an increased effect of warfarin secondary to the drug interaction between ofloxacin and warfarin. When a Fluoroquinolone, such as Ofloxacin, is administered with warfarin, there is a decrease in the metabolism of warfarin, leading to a potentiation of warfarin's pharmacological effect, and an increase in the INR. Although ofloxacin is the most likely answer choice to cause this effect in this patient, the antibiotics most commonly associated with this type of interaction are the: - Macrolides (such as Erythromycin) - Metronidazole - Sulfonamides. Oral doses of penicillins, such as amoxicillin, are generally not associated with a potentiation of warfarin's effect. However, large IV doses of penicillin are associated with a potentiation of warfarin's effect. Cefaclor is a second-generation cephalosporin that can be used in the treatment of acute cystitis. Although this agent is generally not associated with an increased hypoprothrombinemic effect when given with warfarin, the cephalosporins with a methyltetrazolethiol side chain, such as cefazolin, cefmetazole, and cefoperazone, are known to increase warfarin's therapeutic effect. Nitrofurantoin is a urinary anti-infective agent that does not interact with warfarin. Phenazopyradine is a urinary tract analgesic that does not interact with warfarin, although it commonly changes the color of the urine to a bright orange/red color, which may be mistaken as blood in the urine by the patient.

Answer 127

D. Meperidine: Patients with renal dysfunction are at high risk to develop toxicity secondary to the accumulation of compounds that are normally excreted through the kidneys. Meperidine is a narcotic used in the treatment of moderate to severe pain. In renally compromised patients, the hepatic metabolite (normeperidine), which is normally excreted through the kidneys, can accumulate, resulting in the development of myoclonic seizures. Acetaminophen is a non-narcotic often found in narcotic analgesic combination products. Propoxyphene is a narcotic that can accumulate in renal-failure patients resulting in sedation and respiratory depression. Morphine is a narcotic analgesic used to treat moderate to severe pain and can accumulate in patients with renal dysfunction. Ibuprofen is a nonsteroidal anti-inflammatory drug used to treat mild to moderate pain.

Answer 128

D. Thromboxane: Aspirin is a salicylate with analgesic, antipyretic, anti-inflammatory, and antiplatelet effects. Aspirin is bound to albumin, a plasma protein in the blood; it does not decrease the production of albumin. Cyclooxygenase is an enzyme that is inhibited by aspirin; however, its production is not affected by aspirin. Fibrinogen is a precursor of fibrin, which is an elastic filamentous protein that promotes coagulation; fibrinogen production is not affected by aspirin usage. Aspirin (acetyl salicylic acid) inhibits COX-1 (Cyclooxygenase-1 )activity but it does not affect the hydroperoxidase activity of PGH synthase-1. Blocking COX-1 leads to decreased production of Thromboxane A2 (TxA2), leading to decrease in platelet aggregation. Complete inhibition of platelet aggregation by aspirin requires inhibition of TxA2 production by greater than 90%, which requires a dosage as high as 30 mg/day. Aspirin exposure to platelets results in COX-1 deactivation, which remains inactive for the remaining lifespan of the platelet (7– 10 days). This is due to the anucleate nature of the platelets, which are unable to synthesize new, active COX-1. Thus, the restoration of normal platelet function after aspirin administration occurs only with the production of new platelets. Please note that one-seventh of the platelets in the circulation are renewed every 24 h; therefore, up to 30% of circulating platelets may show normal TxA2 production after aspirin is discontinued for 48 h. Consequently, aspirin administration on a daily basis should be preferred rather than administration every second day. It must be stressed that in low doses aspirin does not affect the action of endothelial cell COX-1 and therefore does not reduce the production of Prostaglandin I2 (PGI2), which has many beneficial effects including potent antiplatelet effects. The action of vitamin K as a procoagulant is inhibited by Warfarin, but not aspirin.

Answer 129

B. Buspirone: is an anxiolytic used in the management of anxiety disorders and for short-term treatment of generalized anxiety. This agent is unlike benzodiazepines and barbiturates in that it does not produce a rapid relief of anxiety symptoms. It can take several weeks for patients to experience the antianxiety effects of this agent. Therefore, buspirone should not be used in a patient with acute anxiety. Alprazolam, chlordiazepoxide, and clorazepate are all benzodiazepines used for the management of anxiety disorders; for the short-term treatment of generalized anxiety; and to promote sleep in anxious, tense patients. All three of these agents can produce a rapid relief of anxiety symptoms as well as profound sedation. Phenobarbital is a barbiturate most commonly used in the treatment of seizure disorders. However, phenobarbital could be used in the treatment of anxiety disorders. Like the benzodiazepines, it has a rapid onset of action.

Answer 130

B. Digoxin: The effect of digoxin on the myocardial tissue is dose-related and involves a direct and indirect effect on the cardiac muscle. The indirect effect results in a vagomimetic action that is responsible for decreasing the conduction rate through the AV node (atrioventricular node). Furthermore, this vagomimetic effect causes a depression of the SA node (sinoatrial node). Digoxin is indicated for the treatment of atrial fibrillation, especially when the ventricular rate is elevated, and atrial flutter. In addition to the treatment of cardiac arrhythmias, digoxin is also indicated for the treatment of congestive heart failure. Atropine is an anticholinergic agent that has been used in the treatment of atrioventricular heart block. Atropine increases conduction through the AV node. Lidocaine is indicated for the treatment of atrial and ventricular extrasystoles and atrial and ventricular tachyarrhythmias. Lidocaine has a variable effect on AV node conduction. For the most part, conduction through the AV node primarily remains unchanged. The mechanism of action of lidocaine is related to its ability to reduce the maximal velocity of phase 0 depolarization due to the block of inward sodium current in tissue with fast-response action potentials. Procainamide is a Class IA antiarrhythmic agent indicated for the treatment of ventricular arrhythmias. It often causes AV node conduction to be slightly increased. Its mechanism of action is related to its ability to reduce excitability of the myocardial tissue to electrical stimulation in the atria, ventricles, and His-Purkinje system. Verapamil is a Type IV antiarrhythmic agent that blocks calcium channels, thereby decreasing conduction velocity and increasing refractoriness in tissue with slow-response action potentials. Verapamil is indicated for the treatment of atrial fibrillation and flutter as well as various other atrial tachycardias. Verapamil prolongs AV conduction proximal to the bundle of His, probably due to an intrinsic action.

Answer 131

E. Vasopressin: Central diabetes insipidus is a condition that occurs when there is inadequate synthesis or release of antidiuretic hormone (ADH). Central diabetes insipidus is characterized by the following signs and symptoms: Polyuria, polydipsia, and a urine specific gravity usually less than 1.006 during periods of excessive fluid intake. Since the disease is caused by a deficiency of vasopressin (ADH), the most useful drug in the treatment of central diabetes insipidus is vasopressin. Furosemide is a "loop" diuretic used in the treatment of edema caused by congestive heart failure, cirrhosis of the liver and renal insufficiency. Since urine output in diabetes insipidus is above normal, the use of a diuretic is not indicated. Glyburide is an oral antidiabetic agent used in the treatment of noninsulin dependent diabetes mellitus. The use of glyburide in diabetes insipidus would be ineffective because this agent increases insulin secretion and does not affect ADH blood levels. Along the same lines, the use of glucagon, an agent that increases blood glucose levels, in individuals with diabetes insipidus would be ineffective. Insulin is a natural hormone used in the treatment of both insulin dependent and non-insulin dependent diabetes mellitus. Its usage in individuals with diabetes insipidus would provide no therapeutic benefit.

Answer 132

B. Metronidazole: Very effective against anaerobic gram-negative bacilli, including those that produce beta-lactamase.

Answer 133

D. 0.072 mg: It is best to calculate using epinephrine 1:100,000 first. The carpule contains 1.8 g (mL) of solution. Therefore: 1.8 g = 1,800 mg 1,800 divided by 100,000 = 0.018 mg of epinephrine for each carpule of 1:100,000-type anesthetic A 1:50,000-type anesthetic has twice as much epinephrine, not half as much, so each carpule of 1:50,000 will have 0.036 mg epinephrine and 2 carpules will have 2 X 0.036 mg, or 0.072 mg. Choices A, B and C are therefore incorrect.

Answer 134

D. improves patient compliance and avoids first-pass hepatic metabolism: There is no bypass of the coronary circulation (choice A) -- nitrates actually decrease coronary vasospasm, which makes them effective in treating angina. The sublingual administration of a drug avoids its absorption into the portal circulation and hence eliminates the possibility of first-pass metabolism (choice B), which can often have a major impact on oral bioavailability. Given sublingually, nitroglycerin is more effectively absorbed into the systemic circulation and has improved effectiveness in the treatment of angina. Sublingual administration also improves patient compliance (choice C). Since both choices B and C are correct, choice D is the correct answer.

Answer 135

C. Ipatropium: Chronic obstructive pulmonary disease (COPD) is a respiratory disorder commonly associated with the development of bronchospasm. As the severity of the bronchospasm increases, the patient has increased difficulty in breathing. Along the same lines, when the bronchospasm is treated, the patient is able to breathe normally. Ipratropium: an anticholinergic medication administered via inhalation, and is used as maintenance therapy in COPD, including chronic bronchitis and emphysema. Ipratropium produces a local bronchodilatory effect on the airways. Edrophonium: is a reversible, indirect-acting cholinesterase inhibitor similar to neostigmine. Edrophonium can be used to reverse the effects of neuromuscular blockade produced by nondepolarizing skeletal muscle relaxants. The use of edrophonium in a patient with bronchospasm would worsen the bronchospasm. Homatropine: is a topical anticholinergic agent used as a mydratic for ocular examination. Propantheline: is an anticholinergic agent used in the treatment of irritable bowel syndrome, pancreatitis, and urinary bladder spasm. Propranolol: is a non-selective beta receptor blocking agent commonly used in the treatment of hypertension. The use of propranolol in a COPD patient is not recommended because the medication is known to cause or worsen bronchospasm.

Answer 136

C. Captopril: Treatment of diabetic nephropathy (proteinuria >500 mg/d) in diabetic patients is often made with angiotensin-converting enzyme (ACE) inhibitors. Captopril is an ACE inhibitor indicated for the treatment of hypertension, diabetic neuropathy, and congestive heart failure because it has been proven to preserve ventricular function. This agent is often used for the treatment of hypertension in diabetic patients because it has been shown to preserve kidney function. It decreases the rate of progression of renal insufficiency and the development of serious clinical outcomes, such as renal transplantation and death. Atenolol: is a beta-receptor-blocking agent commonly used in the treatment of hypertension. In insulin-dependent diabetics, beta-blockers can prolong, enhance, or alter the symptoms of hypoglycemia. Beta-blockers can potentially increase blood glucose concentrations and antagonize the action of oral hypoglycemic drugs. Bumetanide: a potent diuretic commonly used in the treatment of edema associated with congestive heart failure and hypertension. However, the use of this medication in diabetic patients is not recommended because it can cause hyperglycemia and glucose intolerance. Diltiazem: a calcium-channel blocker indicated for the treatment of hypertension, supraventricular tachycardias, and various types of angina. It can be used safely and effectively for the treatment of hypertension in diabetic patients; it significantly reduces albuminuria and may slow the progression of proteinuric renal disease, but it is not commonly used for the treatment of diabetic nephropathy. Methyldopa: a centrally acting alpha-adrenergic agonist, can be used to treat hypertension in diabetic patients. However, due to the severity and frequency of adverse effects commonly associated with this medication, it is not commonly used.

Answer 137

D. Cardiovascular toxicity: The key to this question is the distinction between localized and systemic effects. Cardiac and CNS effects, whether depression or stimulation, occur when anesthetic or vasoconstrictor enters the vascular system. These effects are systemic, not local, and include cardiovascular toxicity. The other choices are all localized effects. Hematoma (choice A) is often caused by needle trauma to a blood vessel, trismus (choice B) by needle trauma to the medial pterygoid muscle, and paresthesia (choice C) by needle trauma to a nerve (often the inferior alveolar nerve). Mucosal irritation (choice E) is a local effect of anesthetic or vasoconstrictor in soft tissue from too high a concentration, or too much injected at one time, causing ballooning of tissue or excess vasoconstriction.

Answer 138

A. valve affected and the causative organism are usually different: In acute endocarditis caused by intravenous drug abuse, the right side (tricuspid) valve is affected more often. This is due to bacteria directly entering the venous system through the vein injection. In addition, the causative organism is often staphylococci from the skin. The mitral (bicuspid) valve is most affected by subacute bacterial endocarditis from dental procedures.

Answer 139

A. Atenolol: Hypoglycemic episodes are commonly preceded by specific premonitory signs and symptoms, such as anxiety, sweating, hunger, tremor, confusion, and weakness. The usage of beta-adrenergic blocking agents, such as atenolol, may blunt or prevent the appearance of these premonitory signs and symptoms. Captopril is an angiotensin-converting enzyme (ACE) inhibitor that can safely be used for the treatment of hypertension in diabetic patients. Furosemide is a potent diuretic commonly used in the treatment of edema associated with congestive heart failure and hypertension. However, the use of this medication in diabetic patients is not recommended, since it can cause hyperglycemia and glucose intolerance. It does not decrease the appearance of the normal warning signs and symptoms of hypoglycemia. Methyldopa, a centrally acting alpha-adrenergic agonist, can be used to treat hypertension in diabetic patients. However, due to the severity and frequency of adverse effects commonly associated with this medication, it is not commonly used. Verapamil is a calcium channel blocker indicated for the treatment of hypertension, supraventricular tachycardias, and various types of angina; it can be used safely and effectively for the treatment of hypertension in diabetic patients.

Answer 140

B. Meperidine: Elderly patients with renal dysfunction are at a relatively high risk for developing toxicity due to the accumulation of medications/metabolites that are normally excreted through the kidneys. Meperidine is a narcotic analgesic used in the treatment of moderate to severe pain. In renally compromised individuals, its hepatic metabolite (normeperidine), which is normally excreted through the kidneys, can accumulate, resulting in the development of myoclonic seizures. Since this patient has a past medical history significant for seizure disorders, this medication should not be administered to this patient. Although dosage adjustments of the other analgesics may need to be made in patients with renal dysfunction, they are not associated with the development of seizures in these patients. Acetaminophen is a non-narcotic analgesic indicated for the treatment of mild to moderate pain. It is commonly found in many narcotic analgesic combination products. Naproxen is a non-steroidal anti-inflammatory drug (NSAID) used in the treatment of mild to moderate pain caused by inflammation. The use of NSAIDs for extended periods of time in renally compromised individuals is not recommended since they can decrease renal blood flow. However, short-term usage of NSAIDs in these patients is acceptable. Oxycodone and pentazocine are narcotic analgesics used in the treatment of moderate to severe pain. These agents may accumulate in renal failure patients; however, the resulting toxicity is typically respiratory depression and sedation.

Answer 141

B. Diazepam: Status epilepticus is defined as an episode of repeated seizure activity with impaired arousal lasting for at least 30 minutes. This condition can involve convulsive (generalized tonic-clonic activity) and non-convulsive (absence or complex partial) seizures. Generalized convulsive status epilepticus can be a life-threatening condition. Therefore, the management of this condition requires an immediate cessation of seizure activity due to the risk of hypoxia, aspiration, acidosis, hyperthermia, hypotension, myoglobinuria and various physical injuries. The drug of choice for the treatment of the convulsions is diazepam. Diazepam is a benzodiazepine anxiolytic/anticonvulsant commonly used in the treatment of short-term anxiety and status epilepticus. Albuterol is a beta-adrenergic agonist commonly used to relieve bronchospasm associated with acute or chronic asthma or bronchitis. Since albuterol causes CNS stimulation, its usage in a patient with status epilepticus would not be recommended. Epinephrine is an alpha and beta adrenergic agonist used to relieve bronchospasm and to restore cardiac rhythm in cardiac arrest. Like albuterol, it also causes CNS stimulation and would not be recommended for usage in patients with status epilepticus. Ethosuximide is an anticonvulsant agent used in the management of absence and myoclonic seizures. Since it may increase the severity of grand mal seizures, it would not be used to treat a patient with status epilepticus. Phenytoin is an anticonvulsant commonly used in the treatment of tonic-clonic, psychomotor and nonepileptic seizures. However, this medication is not indicated for the treatment of active seizures because it takes a while to exert its antiepileptic effect; diazepam instantly stops tonic-clonic seizures.

Answer 142

A. alpha-hemolytic strep: The usual cause of subacute bacterial endocarditis due to dental procedures is alpha-hemolytic strep (viridans strep). These organisms are normal flora and include Streptococcus mutans, S. mitis, S. salivarius, and S. sanguis.Beta-hemolytic strep is often linked to the common illness “ strep throat.” Gamma-hemolytic strep are less common and aggressive. Staphylococci indicate a larger gram-positive family that is a common part of the natural human flora.

Answer 143

B. 1-2 hrs Antacids are products that neutralize gastric acid in the stomach, thereby reducing mucosal irritation. Furthermore, these products can increase the stomach pH, which can be beneficial for patients with gastroesophageal reflux disease, because when the intragastric pH is increased above 4, there is an increase in the lower esophageal sphincter pressure. When this occurs, there is a decrease in the classical signs and symptoms of heartburn. Antacids are commonly used in patients with infrequent signs and symptoms of heartburn and as an adjunctive agent in H2-antagonist therapy. One of the disadvantages of antacid usage on a chronic basis is that these products have a very short duration of action. As a general rule, antacids will provide a buffering effect in the intestinal tract for approximately 1 to 2 hours after ingestion. Note: Ranitidine is an effective inhibitor of pentagastrin-induced secretion, and its effect lasts for 8 to 12 hours after administration. After oral administration, the onset of the antisecretory effect of omeprazole occurs within 1 hour, with the maximum effect occurring within 2 hours. Inhibition of secretion is about 50% of maximum at 24 hours, and the duration of inhibition lasts up to 72 hours.

Answer 144

D. To skin test patients for a possible penicillin allergy: Benzylpenicilloyl-polylysine is a skin test antigen that reacts with benzylpenicilloyl skin sensitizing antibodies (IgE) to produce an immediate "wheal and flare" reaction at the site of the injection. This agent is used as an adjunct in assessing the risk of administering penicillin in adults with a history of clinical penicillin hypersensitivity. Individuals who test "negative" have less than a 5% chance of having a hypersensitivity reaction to penicillin. However, individuals, testing positive to benzylpenicilloyl-polylysine, will have greater than a 20% chance of having an allergic reaction to a penicillin.

Answer 145

C. Meperidine: Individuals with renal dysfunction are at a particularly high risk for developing toxicity secondary to the accumulation of compounds normally excreted through the kidneys. Meperidine is a narcotic analgesic used in the treatment of moderate to severe pain. In renally compromised individuals, its hepatic metabolite (normeperidine), which is normally excreted through the kidneys, can accumulate, resulting in the development of myoclonic seizures. Although dosage adjustments of the other analgesics have to be made in patients with renal dysfunction, they are not associated with the development of seizures in these patients. Acetaminophen is a non-narcotic analgesic indicated for the treatment of mild to moderate pain. It is commonly found in many narcotic analgesic combination products. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) used in the treatment of mild to moderate pain caused by inflammation. The use of NSAIDs in renally compromised individuals is not recommended since these can decrease renal blood flow. Morphine is a narcotic analgesic used in the treatment of moderate to severe pain. Morphine can accumulate in renal failure patients; however, the resulting toxicity is typically respiratory depression and sedation.

Answer 146

C. Ciprofloxacin: Anaerobic bacteria are organisms that require a reduced oxygen tension for growth. The nonsporulating anaerobic bacteria exist as part of the normal flora on the mucosal surfaces of humans and animals. The primary reservoirs of these bacteria are the mouth, gastrointestinal tract, skin, and female genital tract. Anaerobic infections occur when the normal balance between aerobic and anaerobic bacteria is disrupted or anaerobic bacteria are introduced into an area that can support anaerobic bacterial growth. The two medications primarily used for the treatment of anaerobic infections are clindamycin and metronidazole. Clindamycin is typically used in the treatment of serious anaerobic infections when other less toxic medications, such as metronidazole, are inappropriate. The fluoroquinolones, such as ciprofloxacin, have very poor anaerobic coverage. Therefore, ciprofloxacin would be relatively ineffective for the treatment of an oral infection caused by an anaerobic organism. These agents are commonly used in the treatment of upper and lower respiratory infections as well as genitourinary tract infections. Amoxicillin/clavulanate is a penicillin antibiotic used in the treatment of a variety of infections caused by gram-negative and gram-positive organisms as well as anaerobic infections. Cefaclor is a second-generation cephalosporin used in the treatment of upper respiratory tract infections caused by gram-negative, gram-positive, and anaerobic bacteria.

Answer 147

B. Antipyrine: The agents listed are used primarily in the treatment of otitis media or cerumen impaction. Antipyrine is commonly added to the otic preparations due to its analgesic properties. Aluminum acetate is often added to an acetic acid solution to make "Burrows" solution. This solution possesses antibacterial and antifungal properties. Both carbamide peroxide and triethanolamine are earwax emulsifiers. Neomycin is an aminoglycoside antibiotic used for the treatment of bacterial otitis media.

Answer 148

D. this product commonly results in a decreased absorption of water-soluble vitamins: Cholestyramine is a bile-acid-binding resin that interrupts the enterohepatic circulation of bile acids by binding with them in the intestinal tract. Once bound, these bile acids are excreted in the feces. This increased fecal loss of bile acids results in an increased synthesis of new bile acids, leading to a decreased LDL cholesterol. LDL cholesterol levels often decrease 4 to 7 days after starting therapy. Because this product binds to bile acids and related compounds, one would expect to see a decrease in FAT-SOLUBLE vitamins, not water-soluble vitamins. Constipation is a common side effect of this product. Because this product comes only in a powder form, it is to be mixed with a liquid before ingesting.

Answer 149

D. Ribavirin: is an antiviral agent used primarily to treat infections caused by the respiratory syncytial virus. This agent interferes with nucleic acid synthesis (DNA and RNA). All of the other agents exert their mechanism of action through the inhibition of viral DNA polymerase. Acyclovir is used in the treatment of herpes simplex virus, varicella-zoster virus, and Epstein-Barr virus infections. Foscarnet is used in the treatment of ganciclovir-resistant CMV retinitis in immunocompromised patients. Ganciclovir is an antiviral used in the treatment of CMV infections. Vidarabine is used in the treatment of resistant herpes simplex infections such as encephalitis.

Answer 150

D. 108 mg: This is a common type of NBDE calculation problem. Remember that the anesthetics are produced in what is known as a gram percent solution. This translates to a number of grams contained in 100 mls of solution. Thus, a 3 percent solution contains 3 grams of anesthetic in 100 mls of solution. 3 grams equals 3,000 mg. So, we have 3,000 mg Carbocaine® per 100 ml solution. Reduce 3,000 over 100 and we get 30 mg per 1 ml. There are 30 mg of Carbocaine® per each 1 ml of solution. Therefore, multiply by the number of mls per carpule to get the final mg's administered. We get 30 times 1.8 or 54 mg per carpule. 2 carpules should have twice as much, or 108 mg of Carbocaine®.

Answer 151

A. Amiloride: Hypokalemia is an electrolyte abnormality that can easily occur secondary to the use of diuretics. Clinical signs and symptoms of mild to moderate hypokalemia include muscle weakness, fatigue, and muscle cramps. Severe hypokalemia can cause flaccid paralysis, hyporeflexia, tetany, and even rhabdomyolysis. Potassium sparing diuretics, such as: - Amiloride - Spironolactone are commonly used in conjunction with other diuretics to prevent the occurrence of hypokalemia. Both ethacrynic acid and furosemide are rapid acting and potent "loop" diuretics that are commonly used in the treatment of hypertension and edema associated with congestive heart failure. One of the primary side effects of these medications is hypokalemia. The "thiazide" diuretics, which include hydrochlorothiazide and indapamide, are also commonly associated with the development of hypokalemia. These two diuretics are commonly used in the initial treatment of hypertension and as adjunctive therapy for the treatment of edema associated with congestive heart failure.

Answer 152

D. Nitroglycerin sustained-release capsules: The patient is brought to the emergency room after experiencing hypotension followed by syncope. This reaction most likely occurred secondary to the interaction between sildenafil and the nitroglycerin sustained-release tablets. Sildenafil is an agent indicated for the treatment of erectile dysfunction. When sildenafil is administered with a nitrate such as nitroglycerin, there is a potentiation of the vasodilatory effect of circulating nitric oxide, resulting in a significant and potentially fatal decrease in blood pressure. Hence, the concomitant usage of sildenafil and nitrate products is contraindicated. None of the other answer choices interacts with sildenafil. Both glipizide and metformin are indicated for the treatment of type 2 diabetes. It is important to note that these agents are known to cause hypoglycemia, which can lead to the development of syncope. However, the question is asking for an interaction between sildenafil and one of the agents, not what agents can cause syncope. Metoprolol is a beta-receptor-blocking agent commonly used in the treatment of angina and hypertension. Verapamil is a calcium-channel blocking agent commonly used in the treatment of angina, hypertension, and cardiac arrhythmias. It is important to note that when both of these agents are dosed too high, the blood pressure can drop precipitously, leading to the development of hypotension.

Answer 153

B. metabolized by hepatic glucuronidation only: Lorazepam may be safer than most benzodiazepines in patients with impaired liver function because it does not require hepatic oxidation, but only hepatic glucuronidation into lorazepam-glucuronide. Additionally, lorazepam causes CNS depression. Although benzodiazepine actions can be reversed, the drug that acts as an antagonist is flumazenil, not naloxone.

Answer 154

A. Angiotensin II is a compound found in the body and is produced in response to low blood pressure. It is a potent vasoconstrictor. The functions of angiotensin II include increasing aldosterone secretion, which in turn increases renal sodium retention as well as water retention. Because it is a potent vasoconstricting agent, it will increase systemic vascular resistance. When blood pressure begins to fall, angiotensin I is converted to angiotensin II through the action of rennin.

Answer 155

C. Promethazine: is a long-acting derivative of the phenothiazines that possesses marked antihistaminic activity as well as sedative, antiemetic and anti-motion sickness activity. Unlike other phenothiazine derivatives, it does not possess extrapyramidal activity. Promethazine is used for the symptomatic relief of various allergic conditions, nausea and vomiting, and the treatment of motion sickness. The antihistaminic effects make it an excellent agent for treatment of a number of allergic conditions. Chlorpromazine, prochlorperazine, thioridazine and triflupromazine are all indicated for the management of psychotic disorders. However, prochlorperazine is primarily used for the management of nausea and vomiting. All of these agents possess anticholinergic, extrapyramidal, and sedative effects in varying degrees; they have mild antihistaminic activity.

Answer 156

B. Cyclobenzaprine: Xerostomia, or dry mouth, is a condition associated with a dryness of the oral cavity resulting from diminished or arrested secretion. Dry mouth is a very common side effect in medications that possess anticholinergic properties because there is a generalized drying of the mucous membranes. Of the medications listed, only cyclobenzaprine has anticholinergic properties. Cyclobenzaprine is a skeletal muscle relaxant commonly used for the treatment of muscle spasms. Captopril is an angiotensin-converting enzyme (ACE) inhibitor used in the treatment of hypertension and congestive heart failure. Although it is not associated with the development of xerostomia, it is known to cause angioedema. Fluoxetine is a selective serotonin-reuptake inhibitor (SSRI) indicated for the treatment of clinical depression. It is commonly associated with generalized anxiety symptoms. Medroxyprogesterone is a progestin used in conjunction with estrogens to help prevent endometrial hyperplasia. Its most common side effects are nausea and vomiting. Naproxen is a nonsteroidal anti-inflammatory drug indicated for the treatment of mild to moderate pain and relief of fever. The most common side effect of this agent is gastrointestinal irritation.

Answer 157

E. Metoprolol: Congestive heart failure (CHF) is a condition in which an abnormality in myocardial function results in a decreased ability of the ventricles to deliver adequate quantities of blood to the body tissues during normal activity or during periods of rest. This pathological condition is termed congestive heart failure because of the edematous state commonly caused by the "backup" of fluid secondary to decreased "pump" function. Previously, beta-blockers were absolutely contraindicated in patients with CHF. However, now they are a standard of care and a necessary part of the medication regimen for mild to moderate CHF. Aspirin is commonly used in patients with cardiovascular disease because of its antiplatelet activity. The use of aspirin in CHF may actually improve signs and symptoms of the disease. Captopril is an ACE inhibitor commonly used in the treatment of CHF because it prevents the "ventricular remodeling" associated with the disease. Furosemide is a "loop" diuretic commonly used to decrease the edema associated with this disorder. Hydralazine is a vasodilator used in the treatment of CHF. It is an arteriole dilator that decreases afterload and increases cardiac output in patients with CHF.

Answer 158

C. Hepatic dysfunction: Halothane is an inhalation anesthetic indicated for the maintenance of general anesthesia. Halothane administration has been associated with two types of hepatic dysfunction. One is characterized by increased serum enzyme levels, and the other is fulminant hepatic failure. The hepatic dysfunction typically develops within a few days to 2 weeks following administration. Patients at particular risk for developing hepatic dysfunction are those with previous closely spaced halothane administrations. Furthermore, there is data to suggest that middle-aged obese females are more likely to develop hepatic dysfunction than are other groups of individuals. Cholelithiasis is associated with the development of one or more gallstones in the gallbladder. Gastritis is an inflammation of the gastric mucosa. Although halothane is not associated with the development of renal dysfunction, this disorder has been seen in patients who receive enflurane. In thrombocytopenia, an abnormally small number of platelets are in the circulating blood.

Answer 159

D. None: Each of the first three options has an error in dosage, time, or route of administration. Ampicillin is used for the non-allergic patient who is unable to take oral medication. The correct dose is 2 g, administered IV or IM 30 to 60 minutes before the procedure.

Answer 160

B. CNS stimulation and cardiovascular stimulation: Vasoconstrictor, normally epinephrine, is both a CNS stimulant and a cardiac stimulant. Its effects include excitability, fear, rapid heart beat (or tachycardia), increased respiratory rate, shaking and a sensation described as a rush, when a wave of stimulation spreads throughout the central nervous system and peripheral nervous system.

Answer 161

• an alpha-adrenergic receptor blocker (alpha-blocker) Examples of selective alpha1-blockers used in medicine: Doxazosin (Cardura) — used to treat hypertension Prazosin (Minipress) — used to treat hypertension Terazosin (Hytrin) — manage mild/moderate hypertension; treatment of benign prostatic hyperplasia (BPH) Tamsulosin (Flomax) — used to treat benign prostatic hyperplasia (BPH) *** These drugs selectively block α1-type receptors but not α2-type. Important: Alpha1-blockers cause orthostatic hypotension, also known as postural hypotension. This is a fainting spell which occurs because of a rapid fall in blood pressure when moving from the supine to the upright position, as in getting rapidly out of the dental chair. The symptoms are similar to simple fainting, however the condition is related to positioning. Note: Other adverse effects include tachycardia, nasal congestion and dry mouth. *** Orthostatic hypotension can also result from centrally acting drugs (i.e., clonidine and methyldopa) and direct vasodilators (i.e., hydralazine and diazoxide) ``` Alpha-blockers inhibit the vasoconstrictor response to epinephrine and levonordefrin. Beta-blockers increase the vasoconstrictor response to epinephrine, but reduce the tachycardia resulting from epinephrine. MAO inhibitors (i.e., phenelzine and tranylcypromine) should not be used with indirectly acting sympathetic drugs (i.e., Tyramine and amphetamines) and with several other drugs such as opioids, especially meperidine. Epinephrine and levonordefrin have exaggerated effects when given with neuron depleting agents like reserpine and guanethidine. ```

Answer 162

Two types of adrenergic agonists: 1.Indirect-acting: are those that cause the release of stored norepinephrine at the postganglionic nerve endings to produce their effects. Tyramine and amphetamines cause release of norepinephrine.  2.Direct-acting: are those that interact directly with the alpha or beta receptors. Direct-acting adrenergic agonists may be receptor selective or receptor non-selective: • Phenylephrine = alpha1 selective agonist • Clonidine = alpha2 selective agonist • Dobutamine = alpha1 and beta1 selective agonist • Terbutaline = beta2 selective agonist • Albuterol = beta2 selective agonist • Epinephrine = alpha1,2 and beta1,2 agonist • Norepinephrine = alpha1,2 and beta1 agonist • Isoproterenol = beta1,2 agonist Remember: Some literature refers to direct and indirect-acting adrenergic agonists as direct and indirect-acting sympathomimetic agents. These terms are almost always synonymous. They are agents that bring about tissue responses resembling those produced by stimulation of the sympathetic nervous system.

Answer 163

Hypertensive crisis

Answer 164

• selective serotonin reuptake inhibitors (i.e., Prozac and Paxil) These two categories (tricyclic antidepressants and serotonin and norepinephrine reuptake inhibitors) of antidepressant drugs significantly increase norepinephrine levels in tissues. In the presence of a vasoconstrictor administered via a local anesthetic injection, the patient could experience significant elevation of blood pressure due to the vasopressor actions of the combination. Note: The selective serotonin reuptake inhibitors (i.e., Prozac and Paxil) have no such effect on norepinephrine in tissues and interaction with a vasoconstrictor like epinephrine is not an issue.

Answer 165

antagonists, dopamine

Answer 166

• acetaminophen (Tylenol) Acetaminophen has no effect on platelets nor the coagulation pathways and does not affect bleeding times or prothrombin times even with high doses. Acetaminophen has two major pharmacological actions: an analgesic effect and an antipyretic (fever reducer) effect. Acetaminophen is not effective enough to reduce severe pain, but it is effective in reducing mild to moderate pain. Acetaminophen is a weak inhibitor of prostaglandin formation. Large doses of acetaminophen can cause liver toxicity. Alcohol can seriously increase the hepatotoxic potential of acetaminophen. There are approximately 100 deaths annually due to liver toxicity produced by ingesting large continuous doses of acetaminophen. Acetaminophen very rarely causes drug sensitivities and can be given to patients having an allergy to aspirin. Note: The current maximum dosage per day of acetaminophen (by the FDA) is 4000mg. Most dental schools abide by an anecdotal dosage of 3200mg max per day.

Answer 167

Pralidoxime

Answer 168

- Atropine sulfate - Carbachol - Glycopyrrolate (Robinul) - Propantheline bromide (Pro-banthine)

Answer 169

- Cough* - Angioedema* - 1st dose hypotension - decreased renal fxn - K retention

Answer 170

Methadone Chemical classification of opioid analgesics: Opium alkaloids: * Morphine * Codeine Synthetic derivatives: • Morphine group: * Hydromorphone (Dilaudid) * Oxymorphone (Numorphan) * Nalbuphine (Nubain) • Codeine group: * Hydrocodone (in Vicodin) * Oxycodone (in Percodan, Percocet and Tylox) Synthetic narcotics: • Meperidine group: * Meperidine (Demerol) * Alphaprodine (Nisentil) * Alfentanil (Alfenta) * Fentanyl (Sublimaze) * Sufentanil (Sufenta) * Diphenoxylate (in Lomotil) * Loperamide (in Imodium) • Methadone group: * Methadone (Dolophine) * Propoxyphene (Darvon)

Answer 171

Hydrocodone & Acetaminophen: Vicodin Codeine & Acetaminophen: Tylenol #3 Oxycodone & Acetaminophen: Percocet IV Fentanyl: Sublimaze

Answer 172

``` MOA: Cell wall o Penicillins o Cephalosporins o Bacitracin o Vancomycin o Cycloserine o Aztreonam o Imipenem ``` ``` MOA: Protein synth o Tetracycline o Aminoglycosides o Chloramphenicol o Erythromycin o Lincomycin o Clindamycin o Azithromycin o Clarithromycin ``` MOA: Biosynth pathways o Sulfonamides o Trimethoprim o Fluoroquinolones (i.e., ciprofloxacin, norfloxacin, levofloxacin, moxifloxacin, and gemifloxacin)

Answer 173

Clindamycin

Answer 174

Penicillin VK It is prudent to use an antibiotic with narrow spectrum of action and one that is bactericidal in order to minimize the development of bacterial resistance. Penicillin VK has these properties. Ampicillin has a broader spectrum of action than penicillin VK and cefaclor is a broad spectrum cephalosporin. Tetracycline and clindamycin are bacteriostatic antibiotics and not bactericidal. Note: The major disadvantage of the penicillins is their rather high incidence of allergic reactions. Approximately 10% of the general population is allergic to penicillins. This incidence probably holds for any of the specific penicillins since there is cross allergy from one to the other. Skin rash (a delayed reaction) is the most prevalent allergic manifestation. Life threatening anaphylaxis can occur, but is very rare, particularly with oral dosing. In non-allergic individuals, penicillins at normal therapeutic doses have virtually no side effects what so ever. Penicillins are bactericidal, that is, they actually cause death of the invading bacteria.

Answer 175

Methotrexate *** Amoxicillin in large doses inhibits the renal tubular secretion of methotrexate, thereby causing higher, prolonged serum levels of methotrexate. Aminopenicillins (ampicillin and amoxicillin) are characterized by the amino substitution of penicillin G. They are able to penetrate gram-negative bacteria more readily than are the natural penicillins or the penicillinase-resistant penicillins. However, the aminopenicillins are not stable to beta-lactamases (penicillinase) of either gram-positive or gram-negative bacteria. Note: Gram-negative bacteria that are susceptible to aminopenicillins include: H.influenzae, some E.Coli, and Proteus mirabilis. Ampicillin (Polycillin, Onipen) and Amoxicillin (Amoxil, Larotid) are used primarily to treat infections such as otitis media, bronchitis, sinusitis, and acute bacterial cystitis caused by susceptible organisms. Compared with ampicillin, amoxicillin has a higher oral absorption, higher serum levels, a longer half-life, and is less likely to cause adverse GI effects (diarrhea). Amoxicillin is given orally; ampicillin can be given orally or IV. Note: Ampicillin and amoxicillin are preferred agents in the treatment of urinary tract infections caused by susceptible enterococci (which are facultatively anaerobic, gram-positive cocci that grow in short chains under extreme conditions mainly in the intestine).

Answer 176

Group 1: Bactericidal Group 2: Bacteriostatic

Answer 177

Penicillin VK Three groups of allergic reactions to the penicillins: Acute (anaphylactic shock): occurs within 30 minutes. Characterized by urticaria, angioedema, bronchoconstriction, GI disturbances, and shock. Death can result in a short time if treatment is not instituted immediately (parenteral administration of epinephrine). Accelerated: occurs 30 to 48 hours after. Manifestations include urticaria, pruritis, wheezing, mild laryngeal edema, and local inflammatory reactions. Not life threatening. Delayed: occurs after 2 to 3 days. Approximately 80-90% of all allergic reactions occurring with penicillin are of this type. Manifested by skin rashes. Hypersensitivity reactions occur in up to 10% of patients receiving penicillin. Manifestations range from a mild rash to anaphylaxis. The rash may be urticarial, vesicular, bullous, or maculopapular. Rarely, thrombopenic purpura develops. ``` Note: A rash is the most common sign of an allergy to penicillin. Remember: The mechanism of action of the fluoroquinolones is inhibition of DNA gyrase, an enzyme that is essential in the transcription, replication, and repair of bacterial DNA. Drugs in this class include ciprofloxacin (Cipro), norfloxacin (Noroxin), levofloxacin (Levaquin), moxifloxacin (Avelox), and gemifloxacin (Factive). Fluoroquinolones are active against many gram-positive organisms and gram-negative aerobes, including Moraxella catarrhalis, Haemophilus influenzae, E. coli, chlamydia,and Mycoplasma pneumoniae. They are not active against Clostridium difficile. These drugs are well tolerated, however, the most common adverse effects are GI (e.g., nausea, vomiting, diarrhea, abdominal pain), CNS (e.g., headache, dizziness, confusion) and dermatologic (e.g., rash, pruritis). ```

Answer 178

Tetracycline  Macrolides  Clindamycin  The tetracyclines are a group of broad-spectrum, bacteriostatic antibiotics that inhibit protein synthesis in the susceptible organism by binding to the 30S ribosome subunit, thereby impeding the binding of aminoacyl tRNA to the receptor site on the messenger RNA ribosome complex. The inhibition of this ribosomal function interferes with the attachment of the growing amino acid chain thus preventing complete formation of peptides from the ribosome. Since no peptides are formed, no proteins are formed. Since proteins are necessary for the bacterial cell to metabolically function, the lack there of will cause a static state in which the bacterium becomes vulnerable to phagocytosis by the body's immune system. Tetracyclines are useful in treating the following infections: • Medical infections caused by susceptible gram-positive and gram-negative bacteria • Infections caused by Mycoplasma, Chlamydia , Protozoa or Rickettsia • Exacerbations of chronic bronchitis • Lyme disease (caused by Borrelia burgdorferi) • Treatment of acne • Treatment of gonorrhea and syphilis in patients allergic to penicillin •Dental: treatment of periodontitis associated with the presence of Actinobacillius actinomycetemcomitans (AA) (i.e., localized aggressive periodontitis)  Important: Tetracyclines are not the drug of choice for Streptococcus or Staphylococcus. Clindamycin is bacteriostatic and is active against most gram-positive (i.e., Streptococcus pneumoniae, viridans, and pyogenes as well as Staphylococcus aureus) and many anaerobic organisms, including the anaerobic gram-negative bacteria Bacteroides fragilis. The macrolides include: erythromycin, clarithromycin, and azithromycin.

Answer 179

* Oseltamivir (Tamiflu) * Zanamivir (Relenza) Oseltamivir (Tamiflu) and zanamivir (Relenza) are antivirals that inhibit influenza virus neuraminidase enzymes, altering virus particle aggregation and release. Tamiflu and Relenza are both used to treat acute illness due to influenza (A or B) infection. Acyclovir (Zovirax) is an antiviral that inhibits herpesvirus DNA polymerase, therefore inhibiting viral DNA synthesis. It is used to treat infections with viruses from the Herpesviridae family (such as Herpes simplex virus 1 and 2, Epstein-Barr virus, or the varicella zoster virus. Amantadine is an antiviral drug used for the prevention and treatment of influenza A virus. The drug has little or no effect on influenza B virus. Amantadine interferes with a viral protein, M2, which is required for the viral particle to become "uncoated" once taken inside a host cell by endocytosis. Note: Amantadine is also used alone or in combination with other drugs to reduce motor symptoms in Parkinson’s disease. The mechanism of action for the antidyskinetic activity of amantadine is different from that of its antiviral activity. Rimantadine is a synthetic antiviral drug that can prevent viruses in cells from multiplying. Like amantadine, rimantadine initially was used to prevent influenza A during flu season, and, if given within 24 to 48 hours after the onset of flu symptoms, to decrease the severity of the flu. Rimantadine is chemically related to amantadine, but has fewer side effects on the nervous system. Note: Rimantadine appears to exert its inhibitory effect early in the viral replicative cycle, possibly inhibiting the uncoating of the virus (similar to amantadine's mechanism of action).

Answer 180

Penicillin VK Penicillin VK is not harmful to the fetus when taken by pregnant mothers. It is not incorporated into bony tissue or in the teeth of children like the tetracyclines. Note: Tetracycline and all members of the tetracycline family are contraindicated in children up to 8 years old and in pregnant women. Tetracyclines have the ability to chelate calcium ions and become incorporated in the bony tissues. The teeth of children who have been given the drug may develop a greenish-brown discoloration. This effect is sometimes seen in the newly erupted teeth of infants whose mothers have received tetracycline during pregnancy. Remember: Penicillins, which are bactericidal against susceptible organisms, disrupt synthesis of the bacterial cell wall and compete for and bind to specific enzyme proteins that catalyze transpeptidation and cross-linking. The enzymes to which they bind are called penicillin-binding proteins (PBPs). They consist of transpeptidases, transglycosylases, and D-alanine caboxykinases and are implicated in the final phases of building and reshaping of the bacterial cell wall while it is growing and dividing.

Answer 181

* lansoprazole (Prevacid)  | * Omeprazole (Prilosec)

Answer 182

* heparin  * warfarin (Coumadin) Heparin inactivates thrombin and prevents the conversion of fibrinogen to fibrin (blood clot); warfarin (Coumadin) interferes with the hepatic synthesis of vitamin-K dependent coagulation factors II, VII, IX and X resulting in the inability of the coagulation pathway to form fibrin (blood clot). Vitamin K is a group of fat soluble vitamins that are essential for the synthesis of coagulation factors II, VII, IX and X, and prothrombin in the liver. Vitamin K will enhance blood clotting rather than inhibit blood clotting. Aspirin inhibits blood clotting by inhibiting platelet aggregation in an irreversible manner. Inhibition of platelet aggregation prevents activation of the coagulation pathway; thus no fibrin (clot) is formed. Aspirin does not affect the coagulation pathway. Discontinuation of aspirin for 5 to 7 days allows for normal clotting time to reappear due to the synthesis of new platelets. Clopidogrel (Plavix) inhibits blood clotting by inhibiting platelet aggregation in an irreversible manner. Thus the effects on blood clotting are the same as aspirin. Clopidogrel (Plavix) does not cause gastric ulcers like aspirin does and is the antiplateletagent of choice in patients with history of ulcers. Note: Clopidogrel, aspirin, abciximab (ReoPro), and anticoagulants (i.e., heparin) are used to lessen the chance of heart attack in people who need percutaneous coronary intervention (PCI), a procedure to open blocked arteries of the heart.

Answer 183

• loperamide (Imodium) Antidiarrheals: • Opiate and opioid derivatives - Loperamide (Immodium): Is an antidiarrheal which acts on intestinal muscles to inhibit peristalsis. Is a member of the opioid family. It does not penetrate the central nervous system like the opioids such as codeine; thus it can be sold over the counter. Has no evidence of drug abuse or dependence (unlike other opioids such as codeine, morphine and meperidine). - Diphenoxylate is an antidiarrheal and inhibits excessive GI tract motility and GI propulsion. Commercial preparations contain a sub-therapeutic amount of atropine to discourage abuse. Diphenoxylate an atropine (Lomotil), unlike loperamide (Imodium), requires a prescription. * Antisecretory: bismuth subsalicylate (Pepto-Bismol) * Adsorbents: attapulgite (Kaopectate) Remember: Laxatives act in the reverse manner of the antidiarrheals and increase the motility of the GI tract. They are used to treat constipation. Examples include: magnesium hydroxide (Milk of Magnesia), castor oil, Metamucil and methylcellulose. Antiemetics: act on the "vomiting center" in the medulla. This center has four different sources of stimuli. The chemoreceptor trigger zone (CTZ) is located outside the blood-brain barrier near the vomiting center in the medulla. It communicates with the vomiting center after input is received from drugs and hormones. The classes of antiemetics are: • Antidopaminergic: • Phenothiazines: prochlorperazine (Compazine) and promethazine (Phenergan) • Benzamides: metoclopramide (Reglan) and trimethobenzamide HCL (Tigan) * Anticholinergics: Scopolamine (Transderm Scop) * Antihistamines: meclizine (Antivert), dimenhydrinate (Dramamine) * Serotonin 5-HT 3 receptor antagonists: ondansetron HCL (Zofran), dolasetron (Anzemet), granisetronHCL (Kytril) and palonosetron (Aloxi)

Answer 184

Interferons Interferons are used for a variety of conditions including: hairy cell leukemia (interferon alpha-2a) chronic hepatitis B (interferon alpha-2b), recurring genital warts (interferon alpha-n3) and treatment of multiple sclerosis (interferon beta-1a). Immune globulins provide passive immunity by increasing antibody titers. Immunosuppressants are drugs such as cyclosporin which prevent organ transplant rejection. Growth factors such as keratinocyte growth factor promote cell proliferation and angiogenesis.

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