Drugs to Treat CHF

Question 1

Vasodilators

Answer 1

Hydralazine, Organic Nitrates, Nitroprusside

Question 2

Drug Options

Answer 2

Vasodilators, ACE Inhibitors, ARBs, Beta-blockers, Positive Inotropic Drugs, Phosphodiesterase Inhibitors, Diuretics

Question 3

Positive Inotropic Drugs

Answer 3

Digoxin, Dobutamine, Dopamine

Question 4

Positive Inotropic and Vasodilator Activity

Answer 4

Phosphodiesterase Inhibitors

Question 5

Effects of Vasodilators in CHF

Answer 5

venodilators: decrease preload –> decrease LVEDV –> decrease CO –> decrease LVEDP –> decrease edema
arteriodilators: decrease TPR –> decrease after load –> increased SV –> increased CO –> increased tissue perfusion; CO improves so much that it does not affect the BP and HR

Question 6

Nitroprusside

Answer 6

venous=arterial vasodilation
balanced decrease in preload and after load
increases cardiac output with minimal changes in BP and HR in CHF

only given IV

Question 7

Organic Nitrates

Answer 7

ventilation > arteriodilation
low doses: decrease preload –> decrease congestion and edema by decreasing CO

high doses: decrease preload and after load

acute Tx with nitroglycerin tablet, chronic Tx with ISDN or Nitroglycerin patch

decrease mortality when ISDN combined with hydralazine

Question 8

Hydralazine

Answer 8

arteriodilator
decrease after load leading to an increase in SV and an increase in CO

decrease mortality when combined with ISDN

Question 9

ACE Inhibitors/ ARBs

Answer 9

decrease after load and preload
decrease afterload –> increase SV –> increase CO
decreases LVEDP: (ventilation, decreased RAA leading to a decrease in salt and water retention)
minimal changes in BP and HR
decreases detrimental remodeling
decrease mortality in CHF

Question 10

Nesiritide

Answer 10

recombinant human B-type natriuretic peptide, activates guanylyl cyclase increasing cGMP causing vasodilation
decreased after load and decreases preload

IV Tx acute decompensated CHF

Question 11

Type III Phosphodiesterase Inhibitors

Answer 11

increase cAMP in heart causing an increase in cardiac contractility and an increase in CO
increase cAMP in vascular smooth muscle causing vasodilation and increasing CO

increasing CO and vasodilation causes minimal BP and HR changes

Drug: Milrinone - used as short term IV Tx of severe acute CHF - can cause pro arrhythmic effect, thrombocytopenia, and hypotension

Question 12

Beta- Blockers

Answer 12

Carvedilol, Metoprolol, and Bisoprolol

slow AV nodal conduction, negative inotropic, slow progression, antiarrhythmic effect

decreases mortality and morbidity
inhibits detrimental cardiac remodeling
initiate dosing gradually with careful monitoring

Tx for compensated CHF

Question 13

Digoxin

Answer 13

Mechanism: directly increases contractility
inhibits Na-K ATPase increasing intracellular Ca increasing contractility

Vagomimetic effects: decrease automaticity in SA node decreasing HR, decreases AV nodal conduction leading to an increase in PR interval causing an AV block)
can lead to tachyarrhythmias and arrhythmias at high doses

DOES NOT DECREASE MORTALITY

Low therapeutic index, Renal Excretion (must be adjusted for renal function)
t1/2= 1.5 - 1.7 days

Question 14

Effects of Digoxin

Answer 14

increase cardiac contractility
increase CO
decrease venous pressure and decrease heart size
decrease HR
diuresis
decrease O2 demand
decrease sympathetic tone decreasing the TPR

Question 15

Uses of Digoxin

Answer 15

CHF with A. fib

decrease V rate in A flutter and A fib

Question 16

Adverse effects of Digoxin

Answer 16

arrhythmias
GI (anorexia, nausea, vomiting, and diarrhea)
visual (blurriness, photophobia, abnormal color vision)
CNS (lethargy, anxiety, nightmares, hallucinations, and delirium)

Question 17

Digoxin Toxicity

Answer 17

Enhanced by: hypokalemia, decreased renal function, hypercalcemia, acidosis, and hypothyroid

Toxicity/plasma levels increased with: diuretics (thiazides)
Toxicity/plasma levels decreased with: cholestyramine, colestipol (b/c decrease digoxin absorption)

Tx of Toxicity: discontinue Digoxin, adjust K+, digoxin immune Fab fragments, treat arrhythmias (with lidocaine or atropine)

Question 18

Beta-Receptor Agonists

Answer 18

Dobutamine and Dopamine

Question 19

Dobutamine

Answer 19

Beta1 receptor agonist, mixed alpha
selective increase in contractility increasing the CO
minimal HR and BP changes

IV Tx of acute CHF

Question 20

Dopamine

Answer 20

vasodilator (D1 receptor agonist) also a positive inotrope (Beta-1 receptor agonist)
(increases contractility increasing CO)
IV Tx of acute CHF

Question 21

Diuretics

Answer 21

thiazides and loops to decrease LVEDP and control congestion

K-sparing to prevent hypokalemia

Spironolactone to decrease detrimental remodeling, decrease mortality and morbidity, risk of hyperkalemia though