Lecture 41

Question 1

Arterial Baroreceptors

Answer 1

• Sense arterial pressure indirectly

- Stretch of the elastic arterial walls

Question 2

Epinephrine

Answer 2

• Adrenaline
• Released from chromamaffin cells of adrenal medulla (endocrine hormone)
• EPI simulations all alpha and beta receptors

Question 3

Beta 1 Mechanism Review: Fight or Flight

Answer 3

• Increased inotropic and chrontropic on heart
• Dilated coronary vessels
• Lipolysis to some extent
• Increases HR and contractility
• Increases systolic AND diastolic BP

Question 4

Beta 2 Mechanism Review: Fight or Flight

Answer 4

• Increases blood flow to skeletal muscles and vasodilation
• Dilates bronchi to increase oxygen intake
• Increases glycogenolysis in muscle/liver
• Increases gluconeogenesis in liver

Question 5

Beta 3 Mechanism Review: Fight or Flight

Answer 5

• Lipolysis

- Relaxes detrusor muscle

Question 6

Alpha 1 Mechanism Review: Fight or Flight

Answer 6

• Vasoconstriction in skin/mesentery

- Increases systemic BP

Question 7

PK of EPI

Answer 7

• Administration via injection, intranasal, and topical to eye
• NOT ORAL (susceptible in liver metabolism)
• IV injection - slowly over 5-10 minutes during CPR
• ER use
• Loses potency after expiration date due to tendency to auto-oxidize (changes from clear to a pink or brown color)

Question 8

Epinephrine Uses

Answer 8

1. Bronchi dilation
2. Anaphylaxis
3. Cardiopulmonary Resuscitation
4. Direct intracardiac Injection
5. Circulatory shock following resuscitation
6. Surgical bleeding
7. Decrease mucosa congestion

Question 9

Bronchi Dilation

Answer 9

• Beta 2 receptor activation
• Treats bronchospasm and severe asthma exacerbation
• Anaphylaxis ==> Use Epipen Autoinjector
• Ana-Kit: SC, IM, IV
• Primatene - OTC inhlaer (D/C due to chlorofluorocarbons)
• Racepinephrine (Asthmanetrin) - OTC inhaler, temporary relief of mild symptoms of intermittent asthma

Question 10

EPI: Antagonist of Histamine

Answer 10

1. Vasoconstricts: decreases mucosal edema (alpha-1)
2. Dilates bronchi (Beta-2)
3. Stabilizes mast cells - increases histamine release (Beta-2)

Question 11

Histamine’s Role in Allergy

Answer 11

1. Dilates and increases permeability of capillaries (edema)
2. Constricts smooth muscle of bronchi
3. Stimulation of mucus secretions

Question 12

Cardiac Resuscitation -Target/Drug

Answer 12

• Beta 1 receptor = cardiac

- Ana-Kit used in cardiac resuscitation

Question 13

Cardiac Arrest Causes

Answer 13

1. Tachyarrhythmias
2. Bradyarrhythmias (Decrease HR and AC conductance)
3. Asystole - no HR/contraction

Question 14

Cardiac Resuscitation Steps

Answer 14

1. First start CPR with electrical defibrillation
2. EPI and vasopressin used to constrict blood vessels (alpha 1 effect and V1 receptors)
3. Main purpose of epi/vasopressin is to increases cerebral/myocardial blood flow during CPR
4. Antiarrhythmic drugs (amiodarone/lidocaine)

Question 15

Direct Intracardiac Injection

Answer 15

• Only in extreme emergencies

- Risks include: myocardial puncture, coronary artery rupture, pneumothorax

Question 16

Circulatory Shock

Answer 16

• Can occur after resuscitation
• IV infuse EPI for symptomatic bradycardia treatment
• Dopamine is first line preferable
• EPI increases the changes of spontaneous circulation

Question 17

Alpha 1 Receptor Vasoconstriction Uses

Answer 17

1. Treats/prevents surgical bleeding when applied topically
2. Administered with local anesthetics to decrease absorption of local anesthetics from site of injection (decreases systemic toxicity and prolongs effect of anesthetic at site)
3. Decreases congestion within mucosa
   (EPI activated)

Question 18

EPI Contraindication

Answer 18

1. Hemorrhagic shock, cardiac disease + coronary insufficiency, cardiac arrhythmias
2. Vasoconstriction

Question 19

Heart Conditions + EPI

Answer 19

Detrimental to contraindicated due to:

1. Increased myocardial oxygen demand
2. Increase HR
3. Proarrhythmic potential
4. Produces vasoconstriction

Question 20

Vasoconstriction + EPI

Answer 20

1. Induced tissue necrosis locally in peripheries and presence of peripheral vascular disease
2. Contraindicated in cerebrovascular disease to hemorrhages
3. Hypertension and hyperthyroidism
4. Diabetes mellitus: hyperglycemia due to increases gluconeogenesis/glycogenolysis

Question 21

Adverse Reactions + EPI

Answer 21

1. Anxiety, N/V
2. Cardiac arrhythmias including sinus tachycardias , palpitations, hypertension - angina results form increased workload and oxygen demands of heart in predisposed patients
3. IV injections/infusions leak cause necrosis to occur due to alpha constriction of vessels

Question 22

Phentolamine

Answer 22

• Regitine
• Alpha receptor antagonist
• Injected locally to reverse tissue necrosis locally

Question 23

EPI Block Box

Answer 23

• Antidote for peripheral ischemia: Regitine
• Immediate and conspicuous hyperemic changes (increased blood flow)
• Give ASAP once extravasation is notices

Question 24

NE

Answer 24

• Acts on postganglionic sympathetic neurons

- Levophed injectable = only one available

Question 25

NE Stimulates...

Answer 25

1. Alpha 1 - vasoconstrictor 2. Alpha 2 - feedback inhibition of release 3. Increases HR and contractility

Question 26

NE PK

Answer 26

- Ineffective orally, administration = IV - Short duration, rapid inactivation and reuptake at synapse - Metabolism by MAO and COMT - NE, like EPI/dopamine, doesn't cross BBB

Question 27

NE CV Uses

Answer 27

1. Acute hypotension - non-volume related hypotension where systolic BP is less than 70 mmHg 2. Cardiogenic/Septic Shock - use NE, vasopressin, antibiotic therapy, and fluid replacement

Question 28

NE GI Use

Answer 28

1. Upper GI Bleeding - administer intraperitoneally or using a nasogastric tube

Question 29

NE Contraindications

Answer 29

1. Don't use in patients who are hypovolemic 0 correct volume first 2. Don't use with mesenteric thrombosis (increases ischemia) 3. Don't use with hypertension/hyperthyroidism

Question 30

NE Adverse Reactions

Answer 30

1. N/V, Anxiety 2. CV - sinus tachycardia, hypertension 3. Tissue necrosis at site of injection 4. Large/repeated doses * *Damage due to formation of toxic quinone**

Question 31

Isoproterenol

Answer 31

- Isuprel - B1/B2 selective Mechanisms: - B1 - increase in inotropic and chronotropic effects, increases systolic BP - B2 - vasodilation, decrease in diastolic CP by direct vasodilation and prevention of histamine and other autocoid release from mast cells (decrease bronchoconstriction and edema)

Question 32

Isoproterenol Uses

Answer 32

1. Cardiac (B1) - Mild/transient episodes of heart block that don't require a pacemaker or electric shock 2. Cardiac (B1) - in cardiac arrest and catheterization 3. Lung (B2) - bronchospasm occuring during anesthesia

Question 33

Dopamine

Answer 33

Endogenous neurotransmitter Dosage Effects 1. Low dose - vasodilates renal, mesenteric, coronary, and intracerebral vasculature 2. Moderate dose - stimulation B1 receptors which increases CO and maintains vasodilation effects 3. High Doses - alpha-adrenergic effects, vasoconstriction

Question 34

PK of Dopamine

Answer 34

1. Admin. continuous IV infusion 2. Rapid onset, short duration 3. No BBB, L-dopa does though 4. Metabolized by MAO and COMT - ~25% converted to NE

Question 35

DA Uses

Answer 35

1. Treats decreased CO, BP, and urinary output that occurs with septic shock, cardiogenic shock, and post-surgical myocardial failure * *Gradually increase dose until affect is achieved, D/C slowly to minimize hypotensive response** 2. Treat hypotension (after resus. or with bradycardia) 3. Stimulates urine output (with oliguria)

Question 36

DA Contraindications

Answer 36

1. Pheochromocytoma (adrenal tumor) 2. Uncorrected ventricular fibrillation and tachycardia, tachyarrhythmias **DA can lead to B-receptor stimulation and indirect release of endogenous NE** CAUTION WITH CARDIAC DISEASE SINCE IT INCREASES OXYGEN DEMAND

Question 37

DA Adverse Reactions

Answer 37

1. PVC - from B-stimulation of myocardium 2. Peripheral vasoconstriction and subsequent hypertension from alpha-stimulation and high doses 3. Hypotension can result from abrupt D/C 4. N/V by dopamine receptors at chemoreceptor trigger zone (D2 receptor at CTZ) 5. Avoid leakage of dopamine from IV site since it leads to tissue necrosis

Question 38

Fenoldopam

Answer 38

- Carlopam - Selective D1-agonist - Short-term treatment of severe hypertension - Peripheral and renal arterial vasodilator produces dose-dependent decreased BP and increases in renal plasma flow which stimulates diuresis and natriuresis - May cause reflex tachycardia, short onset and duration

Question 39

Catecholamine Drug-Drug Interactions

Answer 39

1. Potentiate actions of catecholamine inhibiting enzymes - MAOIs and COMTIs 2. Potentiate NE and DA effects by blocking NE uptake pumps - TCAs, Cocaine, Amphetamine 3. Receptor blockers interfere with postsynaptic catecholamine response 4. Hyperthyroidism - can increase the number of beta receptors in the heart, so take care when using B-agonists including DA

Question 40

Alpha-blocker Drugs

Answer 40

1. Prazosin | 2. Phenothiazines

Question 41

Beta-blocker Drugs

Answer 41

1. Propranolol | 2. Metoprolol

Question 42

DA-Blocker Drugs

Answer 42

Antipsychotic Drugs