Autonomic Antagonists Flashcards Preview

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Flashcards in Autonomic Antagonists Deck (21):
1

What is atropine?

Competitive antagonist for muscarinic receptor's ACh binding site (ie parasympathetic antagonist)

2

What does atropine do to the HR?

inc

3

What does atropine do to the AVN refractory pd

dec

4

What does atropine do to arteriolar vasodilation

dec

5

What do we use atropine clinically for?

-Interrupt or prevent a vagal rxn
-Restore AV conduction in disorders that cause prolonged AV nodal refractoriness
-->inferior wall MI
-->Digitalis intoxication

6

What would a beta 1 antagonist do?

-Dec HR
-Dec velocity, inc refractoriness
-Dec myocardial intotropy and metabolic rate
-Inhibit renin release

7

What is prazosin?

Competitive alpha 1 antagonist (with a little alpha 2)
-inhibits vasoconstriction decreasing PVR and BP

8

Side effect of prazosin?

postural hypotension

9

What are doxazosin and terazosin

pure alpha 1 antag that have a slower onset and longer duration than prazosin

10

Why does a greater lipid solubility of a drug matter?

Greater lipid sol=more readily penetrates BBB

11

Which beta blockers are lipophilic?

propranolol, metoprolol (abs in GI, metab by liver, short T1/2)

12

What beta blockers are hydrophilic?

Atenolol (longer T1/2, renal metab)

13

What is propranolol?

Non selective beta blocker with high lipid solubility, short half life and hepatic elimination and low bioavailability

14

What is metoprolol?

Beta 1 antagonist with moderate lipid solubility, high bioavailability and hepatic elimination

15

What is atenolol

Beta 1 blocker with low lipid sol, 40% bioavailability and renal elimination

16

What is carvedilol?

Non selective beta blocker with additional alpha 1 blockade, moderate lipid sol, hepatic elimination

17

What CV conditions do we use beta blockers for?

HF, MI, Angina, Arrhythmias, hyperT
-->don't give with complete heart block or cardiogenic shock

18

Adverse effects of beta blockers

-Sinus bradycardia, sinus arrest AV block
-Reduced LV contractility in severe symptomatic HF
-Bronchoconstriction
-Fatigue, mental depression, nightmares, sexual dysfxn
-Raynaud's precipitation
-Worsening of limb ischemia with severe PVD
-Withdrawal (tachy arrhythmias, angina etc because beta1 receptors become upregulated with chronic use)
-Inc TGs, dec HDL
-Can mask symptoms of hypoglycemia in diabetes

19

Do we use beta blockers for cardiogenic shock?

NO WAY! He has to do whatever he can to maintain output, including very increased HR.

20

Who are the ideal pts for beta blocker use?

-Physical activity induces attacks of angina
-Coexistent hyperT
-Hx of supraventricular or ventricular arrhythmias
-Previous MI
-Left ventricular systolic dysfxn
-Mild to moderate HF symptoms
-Prominent anxiety state

21

Poor candidates for beta blockers

-asthma/lung disease
-SEVERE LV dysfxn with HF
-Hx of depression
-Raynauds
-Symptomatic peripheral vascular disease
-Brittle diabetes
-Severe bradycardia or heart block