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16 Cards in this Set
- Front
- Back
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Digoxin MOA?
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inhibits Na/K ATPase of the cell membrane, leading to a small increase in intracellular Na. Increased Na makes Na/Ca exchanger pull out less Ca. Increased intracellular Ca is stored in sarcoplasmic reticulum to be released on contraction.
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Mechanical effects of Digoxin?
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increased ventricular ejection, decreased end-systolic and end-diastolic size, increased CO, increased renal perfusion. These all lead to decreased sympathetic tone - reduced HR, preload and afterload
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Electrical effects of Digoxin?
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Early: decreased AV conduction velocity, long AV node refractory period
Late: Short QT, T inversion, ST depression |
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Digoxin toxicity?
Tx? |
arrhythmias, n/v, diarrhea
1.Correct K/Mg deficiency 2. antiarrhythmics 3. digoxin antibodies |
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Digoxin drug interactions?
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Quinidine = reduced dig clearance
K, Mg = inhibit dig effects (loop diuretics and thiazides may induce toxicity) Ca = enhance dig effects |
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Furosemide vs. spironolactone/eplerenone?
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Furosemide = acute HF
Spironolactone = long-term benefits |
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Beta1 adrenoceptor agonists?
Use? |
Dobutamine (B1 selective)
Dopamine used when systolic fxn is depressed |
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Phosphodiesterase Inhibitors?
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Amrinone, milrinone
increase cAMP by inhibiting degrading enzyme = increased cardiac intracellular Ca; also cause vasodilation |
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Vasodilators?
Use? |
nitroprusside, NTG, hydralazine, nesiritide
acute severe failure w/ congestion |
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When should you NOT use phosphodiesterase inhibitors?
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chronic failure
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recombinant BNP administered via IV for acute failure?
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Nesiritide
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general treatment plan for acute heart failure?
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1. Loop diuretic
2. If severe, a prompt positive inotropic agent (b-agonist or phosphodiesterase inhibitor) and vasodilators |
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general treatment plan for chronic heart failure?
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diuretics (loop + spiro)
ACE-inhibitor b-blocker |
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anti-arrhythmic with no value in heart failure?
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Ca-channel blockers
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parasympathetic effects of digoxin (slowed AV conduction/long PR) can be blocked by what drug?
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Atropine
(muscarinic PANS blocker) |
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What does digoxin NOT do in heart failure?
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decrease mortality
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