Cardiac glycosides and others drugs for CHF Flashcards Preview

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Flashcards in Cardiac glycosides and others drugs for CHF Deck (11):
1

Prototype cardiac glycosides

digoxin

2

Therapeutic effect of digoxin

positive inotropic effect, increases force

3

MOA of digoxin

direct- inhibits Na+/K+ ATPase which decreases Na+/Ca++ and increase intracellular Ca++ allows heart to beat more forcefully
indirect- parasympathomimetic

4

Contraindication of digoxin

worsens ventricular tachycardia because digoxigen acts on ventricular tissue to decrease refractory period and increase conduction velocity

5

Pharmacokinetics of digoxin

40 hour half life, for quick action need a loading dose. Can be degraded by intestinal bacteria, interaction with antibiotics.

6

Toxicity of digoxin

toxicity is only 3 fold greater than therapeutic dose
toxicity is usually due to K+ depletion combined with digoxin therapy, low K+ increases binding to Na+/K+ exchanger
Can lead to ventricular tachycardia and fibrillation

7

Side effects of digoxin

GI, CNS, visual effects, Male breast enlargement

8

Treatment of digitalis toxicity

Monitor ECG, adjust K+ levels, lidocaine for ventricular arrhythmias, emergency: Digibind

9

Drug interactions with digoxin

K+ depleting diuretics, quinidine increases plasma concentrations, antibiotics can decrease metabolism

10

Other drugs used in heart failure (6)

Diuretics
Ace inhibitors
Beta blockers
angiotensin receptor antagonists
Aldosterone antagonists
vasodilators

11

Cardiac toxicity of digoxin

1. premature ventricular beat
2. ventricular tachycardia and fibrillation
3. AV junctional rhythm
4. AV block