CHF drugs Flashcards
What is the effect of vasodilators?
decrease venous return, preload, afterload
What is the treatment for Acute Heart Failure after an MI?
Positive ionotropes and phosphodiesterase inhibitors to increase contractility
D1 agonists to decrease blood pressure/peripheral resistance
What are the positive inotropes for Acute Heart Failure?
Dobutamine IV, Dopamine IV (no increase in HR)
Amrinone & Milrinone IV –> phosphodiesterase inhibitors
What is the D1 agonist and what is it used for?
Fenoldopam - used to decrease blood pressure in acute heart failure
What are signs of Chronic congestive heart failure?
Fatigue, decreased exercise tolerance, edema, dyspnea, Tachycardia, cardiomegaly
Which class of drugs reduces fluid retention?
Diuretics
What are the potassium wasting diuretics
Lasiks, Furosemide, thiazides
What are the potassium sparing diuretics
Spironolactone - inhibits aldosterone receptor
Do ACE inhibitors and AT II Receptor Blockers increase or decrease serum potassium?
Increase serum potassium.
How do phosphodiesterase inhibitors work and what are the name of the drugs?
they block breakdown of cAMP, drugs are named Amrinone and Milrinone
What are vasodilators used to treat CHF?
Phosphodiesterase inhibitors, Hydrazaline, Isosorbide dinitrate, Alpha 1 blockers, Beta blockers, combined alpha/beta blockers, cardiac glycosides
What are the alpha 1 blockers used to treat CHF?
Prazosin, Doxazosin, Terazosin
What are the beta blockers used to treat CHF?
Bisoprolol and Metoprolol
What are the combined beta and alpha blockers?
Carvedilol and Labetalol
What is the primary cardiac glycoside used?
Digoxin
Why do you need to be careful with dosing of Digoxin?
Digoxin has a narrow therapeutic index due to its 36 hour half life. It has slow tissue distribution, so very high blood levels for long periods of time. Double dosing can cause Digoxin toxicity
What drugs does Digoxin have interactions with?
Verapamil and Quinidine
What are the mechanism of action for Digoxin for CHF treatment
Inhibits cardiac Na+/K+ ATPase (increasing Na+ and Ca2+ levels, increases vagal tone, sensitizes vagal afferents to reset baroreceptors (less reactive to changes in BP), and inhibits renal Na+/K+ ATPase (Na+ stays in lumen, dragging water with it)
How do potassium levels effect digoxin effectiveness?
If potassium levels are high, less digoxin can bind. If potassium levels are low, more digoxin can bind. The more digoxin that binds, the greater the force of the contraction.
How do cardiac glycosides treat supraventricular tachycardias?
Decrease AV nodal conduction velocity and by increasing vagal tone
What things can increase cardiac glycoside toxicity?
Hypercalcemia - ectopic foci Hypokalemia - augments digitoxin binding Hypomagnesia Acidosis - triggers arrhythmias Drug interaction with verapamil or quinidine
What are effects of digitoxin toxicity?
ectopic foci, arrhythmia, bigeminy (every other beat is abnormal - sinus, PVC, sinus, PVC), 2nd degree AV block
How do you treat digitoxin toxicity
add potassium (unless hyperkalemia), stop drug, give Digibind (binds to digitoxin), Phenytoin (inactivates sodium channels)
What are side effects of digitoxin?
N/V, Blurred vision, hallucinations, vertigo, headache, cardiac arrhythmia (bigeminy)
When is digitoxin contraindicated?
with Wolff-Parkinson White syndrome
What Beta agonists can be used in the treatment of CHF?
Dopamine and Dobutamine
What D1 agonists are used in the treatment of CHF?
Fenoldopam and Dopexamine
promotes dilation of arterioles used in CHF with hypertensive crisis
what is nesiritide and what is it used for?
naturetic peptide of the brain, vasodilates, reducing ventricular filling pressures and improving CO
What is Coenzyme Q? How does it work?
Free radical scavenger that supposedly decreases cardiac damage. Not proven to increase efficacy but shouldn’t hurt patients
