Finals Identification Flashcards by Justine Aquino

is the study of the biochemical and physiological effects of drugs and their mechanism of action. It is the response of the organism to the action of a drug in the absence of a disease. ____ is ‘what the drug does to the body’.

Pharmacodynamics

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When tissues are continuously exposed to an agonist, the number of receptors decreases and this may lead to a reduction in the number of receptors. This may be a reason for tachyphylaxis.

Down regulation

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As the name indicates this refers to the plotting of the dose vs response, with the dose in X axis and response in some measurable units in the Y axis. The features of the curve so obtained will provide useful information about the action of the drug or in comparison among drugs

Dose response curve

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reduce the volume of gastric juice without changing pH but produce intolerance side effect.

Atropine drug

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is the requirement of higher dose to produce given response

Tolerance

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due to over dosage. examples are Paracetamol induced liver damage, coma by barbiturates, auditory disturbance in streptomycin.

Toxic effect

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appearance of toxic effects at therapeutic doses in some individuals.. eg..only few doses of carbamazepine ataxia in some patients

Intolerance

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ability to cause fetal abnormalities eg.. thalidomide, anticancer drugs, tetracyclines.

Teratogenicity

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Preganglionic fibres originate in the midbrain ( 3rd (oculomotor) cranial nerve), medulla oblongata (7th (facial), 9th (glossopharyngeal) and 10th (vagus) cranial nerves) and 2nd – 4th segments of sacral spinal cord.

Parasympathetic Nervous system/Craniosacral outflow

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preganglionic fibres originate in the intermediolateral columns of spinal cord from the 1st thoracic to the 3rd lumbar vertebrae

Sympathetic nervous system/Thoracolumbar outflow

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has a rapid onset of action. But it is not an ideal antacid due to the rebound acidity. (stimulation of acid production once the pH exceeds 4, due to gastrin secretion)

Sodium bicarbonate

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are agents that mimic the effects of the endogenous regulatory compound. ____ may be defined as drugs that possess affinity for a particular kind of a receptor and has the ability to cause a change in the receptor that gives rise to an observable effect. Their value in clinical practice often rests on their greater capacity to resist degeneration and thus acts for a longer duration than the natural substances they mimic. For this reason, bronchodilatation produced by salbutamol lasts longer than that induced by adrenaline.

Agonists

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Prolonged contact with an antagonist leads to formation of new receptors and this phenomenon is known as

up regulation

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refers to the range of concentrations over which an agonist produces increasing responses. ____ amount of drug required to elicit a response.

Potency

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individual less sensitive to drug (rabbits)

Natural

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genetically determined abnormal reactivity to a chemical and also some uncharacteristic reactions to drugs egg. Barbiturate induced excitement and confusion in some patients.

Idiosyncrasy

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(iatrogenic – physician induced)—examples are ulcer by NSAIDs.

Drug induced diseases

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In organs receiving both sympathetic and parasympathetic innervations the effects of the two divisions are usually

opposed or antagonistic

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chloride that is formed due to the reaction of hydrochloric acid and aluminium hydroxide often causes constipation. It also binds with tetracycline to inhibit its absorption.

insoluble aluminum

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is a measure of its capacity to bind to the receptor. Affinity may vary greatly among agonists as well as antagonists. Intrinsic activity is a measure of the ability of the agonist-receptor complex to initiate the observed biological response. A full agonist has an intrinsic activity of 1.

Affinity of a ligand (drug or endogenous substance)

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This term refers to the production of a maximal tissue response when only a fraction of the total number of receptors is occupied.

Spare receptors

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more meaningful than absolute potency
-Eg. Drug A (potency 10mg) more potent than drug B (100 mg)

Relative potency

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by repeated use of the drug in an individual who was initially responding – may be due to faster elimination of the drug on long use or changes in receptor sensitivity (downregulation)

Acquired

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immunologically mediated reaction – not related to the action of the drug ( hypersensitivity but not super-sensitivity) – needs a priming dose and the second dose produces violent reactions. drug acts as antigen (hapten) and capable of stimulating the body to produce Antibodies against it.

Drug allergy

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refers to a sequence of experiments and characterization using a variety of biologic assays at the molecular, cellular, organ system, and whole animal levels to define the activity and selectivity of the drug. For example, anti- infective drugs may be tested against a variety of infectious organisms some of which are resistant to standard agents.

Drug screening

In organs receiving dual innervations with the influences of the two divisions in the same direction and effects are complementary. Example: salivary glands (salivary secretion is viscous and scanty with ____ and profuse and watery with parasympathetic tone)

sympathetic tone

The absorption of ____ may result in hypercalcemia (muscle weakness, kidney stone formation) and rebound gastric acidity. Constipation may occur with high doses.

~10% of calcium chloride

is a measure of the ability of the agonist-receptor complex to initiate the observed biological response.

Intrinsic activity

The concentration of an agonist that produces half maximal effect is known as

EC50

the maximal effect produced by a drug and refers to the peak obtained in the DR curve.

Efficacy

tolerance among closely related drugs ( morphine and pethidine )

Cross tolerance

These are membrane receptors that are coupled directly to ion channels and are the receptors on which fast neurotransmitters act. Examples include nicotinic acetylcholine receptors and glutamate receptors.

Type I – Channel linked receptors (ligand-gated ion channels or inotropic receptor) – These are also known as ionotropic receptors.

is also known as the visceral, vegetative or involuntary nervous system widely distributed throughout the body controlling the so called autonomic or vegetative functions. The ____ regulates activity of structures like the smooth muscles, cardiac muscle and secretory glands other than endocrine glands. The ____ is responsible for maintaining respiration, blood pressure, heart rate, eye function, gastrointestinal activity, urinary output and virtually all visceral functions within well defined, physiologic limits

autonomic nervous system

In organs receiving only single innervations from one or the other division of ANS, the neuronal control level of function is by

increasing or decreasing activity

causes prolonged neutralizing effect due to slow stomach emptying. Poor absorption of magnesium salts may result in diarrhoea. Combinations of aluminum or calcium containing antacids with magnesium containing antacids can nullify the adverse effects on bowel function.

Magnesium hydroxide

reflects the upper limit of the dose-response relationship without toxic effects being evident. Agonists differ from each other in this regard

Maximal efficacy

The concentration of an antagonist that produces half maximal inhibition is known as

IC50

due to biological variation ( diff. among individuals in response to same treatment) the response to drug dose in a population occurs as a frequency distribution.

Quantal dose response curve

rapid development of tolerance – after only a few doses

Tachyphylaxis

They are membrane receptors that are coupled to intracellular effector systems via a G-protein. This class includes receptors for many hormones and slow transmitters. Examples include muscarinic acetylcholine receptors and adrenergic receptors.

Type II – G-Protein coupled receptors (metabotropic receptors) – These are also known as metabotropic receptors or 7-transmembrane spanning receptors.

regulates activity of structures like the smooth muscles, cardiac muscle and secretory glands other than endocrine glands.

Autonomic Nervous System

are agents that increase the volume of saliva, thereby increasing the appetite and the digestibility of food. Such remedies are used in large animal practice as ‘tonics’.

Sialogogues

Endogenous histamine released from enterochromaffin-like cells or mast cells stimulates parietal H2 receptors. Histamine activates a cyclic AMP pathway, activates H+_ K+-ATPase and leads to increased H+ in gastric lumen. H2 receptor antagonists can block this histamine induced secretion and are helpful reducing the acid secretion during ulcers.

Histamine H2 receptor antagonists

amount of drug required to elicit a response

Potency

Type I – Channel linked receptors (ligand-gated ion channels or inotropic receptor) – These are also known as ionotropic receptors.

The dose that produces desired effect in 50%

ED50

may be trivial, serious or fatal can be seen, these are known adverse effect of drugs. All drugs are capable of producing side effects

Any undesirable or unintended consequence of drug administration

These are membrane receptors that incorporate an intracellular protein kinase domain within their structure. They include receptors for insulin, various cytokines and growth factors. Closely related are receptors linked to guanylate cyclase such as the atrial natriuretic factor receptor.

Type III – Kinase-linked receptors

is responsible for maintaining respiration, blood pressure, heart rate, eye function, gastrointestinal activity, urinary output and virtually all visceral functions within well defined, physiologic limits. involuntary, innervates smooth muscle, cardiac muscle, glands, etc., at neuroeffector junctions.

Autonomic Nervous System

are agents that decrease the volume of salivary secretions.

Antisialagogues (antisialics)

exhibits antiandrogenic properties leading to decreased sperm count, gynecomastia and also inhibits hepatic drug metabolism.

Cimetidine

are agonists that produce a maximal response by occupying all or a fraction of receptors.

Full agonists

Type II – G-Protein coupled receptors (metabotropic receptors) – These are also known as metabotropic receptors or 7-transmembrane spanning receptors.

The dose that produces death in 50%

LD50

based on the pharmacological properties of the drug. Eg.- Side effects, toxic effects and drug withdrawal symptoms

Predictable (type I)

though some are actually located in the cytosol rather than the nuclear compartment. They include receptors for steroid hormones and thyroid hormone

Type IV – Receptors that regulate gene transcription (nuclear receptors) – These are also known as nuclear receptors

is the first link in the reflex arcs of the ANS. It arise from visceral structures. this is generally non myelinated and Cell bodies are in the dorsal root ganglia of spinal nerves and sensory ganglia of cranial nerves. It convey information to the brain and then to the system to be acted upon by efferent.

Afferent fiber

are agents that increase the tone and function of stomach and increase appetite.

Stomachics

is 5 times more potent then cimetidine (Longer duration of action with 24 hours acid suppression is obtained clinically because of high potency). It also have Prokinetic activity along with no antiandrogenic action.

Ranitidine

are drugs that act both as agonists and antagonists. These drugs in addition to blocking access of the natural agonist to the receptor are capable of a low degree of activation. These agents produce less than a maximal response even when they occupy all of the receptors.

Partial agonists

Type III – Kinase-linked receptors

Influence the conc. achieved at the site of action. Doses are normally given for adults of medium build. In extreme cases – dose to be actually calculated based on per kg dose. Body surface area is also an important parameter- used in calculation of dose for anticancer drugs.

Body size

based on peculiarities of the patient and not on known drug effect.

Unpredictable (type II)

cutaneous reaction due to drug induced sensitization of the skin to UV light or radiation.

Photosensitivity

In ____ two neurons (Preganglionic and Post ganglionic fibres) + effector cells / target organs are generally involved

efferent fibers

are agents that promote gastric motility and thus hasten the process of emptying of the gastric contents into the intestine, because of their ability to evacuate the gastric contents they are of value as antiemetics.

Prokinetics

are also called as acid blockers. ____ break down in the acid environment of the stomach and must be given orally as enteric coated preparations (Pantoprazole also available in injection for i/v) and they have short plasma half-lives but are long acting.

Proton pump inhibitors

Some substances produce effects that are specifically opposite to those of agonists and are called as

inverse agonist

These are also known as nuclear receptors, though some are actually located in the cytosol rather than the nuclear compartment. They include receptors for steroid hormones and thyroid hormone

Type IV – Receptors that regulate gene transcription (nuclear receptors)

drug behavior differs in infants and children. – low GFR, Blood Brain Barrier more permeable, absorption is altered poor metabolizing capacity up to 4 weeks of age

Age

expected effect and unavoidable – eg.. dryness of mouth in atropine treatment

Side effect

psychological – patient feels that he will be alright only if he takes the drug

Dependence

Exit the spinal cord and terminate in ganglia. These fibers originated in the midbrain ( 3rd (oculomotor) cranial nerve), medulla oblongata (7th (facial), 9th (glossopharyngeal) and 10th (vagus) cranial nerves) and 2nd – 4th segments of sacral spinal cord. are long and usually synapse on or within the target organ in the ciliary ganglion (3rd cranial nerve), submandibular ganglia (7th cranial nerve) otic ganglion (9th cranial nerve), terminal ganglia in the heart, lungs, liver, spleen, GI tract, kidney (10th cranial nerve). These fibres originate in the intermediolateral columns of spinal cord from the 1st thoracic to the 3rd lumbar vertebrae

Preganglionic fiber

are agents which neutralize excess acid.

Antacids

may be considered as derivatives of prostanoic acid, though prostanoic acid does not naturally occur in the body. have a role to play in midterm abortion, though delayed and erratic action may be a problem – luteolysis. This activity of PGF2α is used for oestrous synchronization in cattle.

Prostaglandins

are agents that are themselves devoid of any intrinsic activity but cause the effects by inhibition of the action of an agonist.

Antagonists

Many hormones, neurotransmitters, autacoids and drugs act on specific membrane receptors, the immediate consequence of which is activation of a cytoplasmic component of the receptor, which may be an enzyme such as adenylate cyclase, guanyl cyclase or activation of a transport system or opening of an ion channel.

Second messenger systems

delayed absorption, plasma albumin falls, acid glycoprotein increases, renal blood flow increases, induction of CYP 450] enzymes – all these affect the kinetics of drug. Besides – possibility of drug affecting fetus or the young ones thro’ milk.

Pregnancy induced changes

indirect consequences of a primary effect. examples are weakening of host immunity by corticosteroids flare up of TB.

Secondary effect

for non addictive drugs.. eg.. seizures on withdrawal of an antiepileptic drug.

Withdrawal reactions

Exit from ganglia and innervate the effector cells /organs

Postganglionic fibres

has a rapid onset of action. But it is not an ideal antacid due to the rebound acidity. (stimulation of acid production once the pH exceeds 4, due to gastrin secretion)

Sodium bicarbonate

is a complex of sulfated sucrose and aluminum hydroxide and is known as gastric band aid. Sucralfate polymerizes to a viscous gel at a pH less than 4. It combines with proteins and adheres to ulcer forming a barrier resistant to acid and pepsin and binds to bile salts which are implicated in ulcer pathogenesis.

Sucralfate

Finals Identification Flashcards

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