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Flashcards in 1 - Cardiac Glycosides Deck (17):
1

What is the inability of the heart to provide the necessary output called?

Congestive Heart Failure

2

What complicates CHF?

  • Insufficient bloodflow, reflex sympathetic output
    • Increases heart rate, peripheral resistance, O2 demand

3

What's the target drug therapy for congestive heart failure?

  • Block sympathetic nervous system***

4

What are the symptoms of acute CHF?

  • Tachycardia
  • Shortness of breath
  • Edema
  • Decreased exercise tolerance

5

What are the symptoms of chronic CHF?

  • Various arrhythmias
  • Hypertension
  • Cardiomegaly
  • Edema

6

What are the symptoms of Right side heart failure vs Left side?

  • Right Side
    • Fatigue
    • Dyspnea
    • Edema
  • Left Side
    • Reduced cardiac output, blood pressure
    • Pulmonary congestion
    • More acute

7

What are the goals when treating CHF?

  • Slow heart rate - increase filling time
  • Increase contractile force to improve ejection fraction
  • Increase cardiac output
  • Reduce retention of salt and water
  • Decrease sympathetic nervous system

8

What is the drug of choice for treatment of congestive heart failure?

  • digoxin (Digitek, Lanoxin)
    • from foxglove plant

9

What is the mechanism of action for digoxin?

  • Inhibits Na/K ATPase pump
    • Increases contraction of heart
    • Postive inotropic effect
  • Directly suppresses AV node conduction to increase ERP and decrease conduction velocity
  • Slows heart rate - negative chronotropic effect

10

Why do glycosides cause diuresis?

  • Decreases venous return
  • Allows heart to become efficient
  • Decreases filling pressure, heart rate and heart size

11

What are the problems with cardiac glycosides?

  • Can be blocked by atropine (increased vagal output)
  • Uncoordinated arrhythmias can arise
  • Low therapeutic index - 50-60% of toxic dose,
    • every patient must be titrated

12

What are the signs of digoxin toxicity?

  • Bradycardia - decreased cardiac output
  • Extra beats (extrasystoles)
  • Causes arrhythmias
  • GI effects - nausea/vomiting, salivation, diarrhea
  • CNS - headache, fatigue, drowsy, green/yellowish aura

13

What is the antidote for digoxin toxicity?

Digoxin immune fab (Digibind, Digifab)

14

How can you treat digoxin toxicity?

  • Potassium chloride and anti-arrhythmic medications

15

Remember - lowering potassium potentiates the effects of ________, and increases potassium acts like an antidote of toxicity which is _________?

  • Digitalis 
  • Digoxin immune fab

16

Other than digoxin, what are other helpful drugs for congestive heart failure?

  • ACE inhibitors
  • B1 agonists
  • Vasodilators

17

What's a summary of cardiac glycosides?

  • Increase force of myocardial contraction
  • Decrease firing of SA node
  • Increased automaticity
  • Slowed AV conduction
  • Prolonged refractory period of AV node
  • Diuresis
  • Decreased venous pressure
  • Decreased tachycardia
  • Decreased heart size