Exam 2: Heart Failure Drugs Flashcards
What is used to treat the problems associated with increased preload in HF?
* Increased SNS and RAAS = increased venous return, increased blood volume, and increased venous tone*
Venodilators
What is used to treat problems associated with afterload in HF?
* increased SNS and RAAS= increased peripheral resistance via arterial constriction*
Arteriodilators
What is used to treat the problems with decreased contractility in HF?
*myocardial fibers are stretched too much as ventricles become dilated
Inotropic drugs
In heart failure, what drugs are used to combat reflex tachycardia?
* decreased cardiac output= increased baroreflex activation= increased SNS stimulation at the heart*
B-blockers, will reduce cardiac work by slowing the HR
What are the 5 classes of drugs that decreased HF mortality?
Aldosterone antagonist, B-blockers, ARBs, ACE inhibitors, and ARNI
What are the 3 effects of angiotensin in the heart?
1) direct vasoconstriction, resulting in a rapid pressor response
2) Increase Na+ reabsorption, resulting in slow pressor response
3) Vascular and cardiac hypertrophy and remodeling
What is the MOA of ACE inhibitors?
Inhibit angiotensin from being formed by blocking ACE
What is the MOA of ARBS?
Angiotensin II antagonists, block ATII from binding to the AT1 receptor
What are the two types of RAS inhibitors?
ACE inhibitors and ARBs
What are the indications for RAS inhibitors?
- Effective in treatment of HF
- Reduce HF mortality
- Diminish cardiac workload by decreasing afterload and preload
What is the DOC for HF treatment?
ACE inhibitors
What are the adverse effects of RAS inhibitors?
Cough with ACE, but not with ARB because of the reduction of bradykinin metabolism
What two drugs make up ARNI?
Sacubitril (neprilysin inhibitor)
Valsartan (ARB)
What does neprilysin do?
Degrades natriuretic peptides, bradykinin, and other
What are the indications for ARNI?
HF- better at reducing mortality in HF than ACE inhibitors alone
What effects does neprilysin inhibition have?
- Decreased vasoconstriction
- decreased sodium retention
- decreased cardiac remodeling
What are the adverse effects of ARNI?
- Hypotension
- Hyperkalemia (ARB) especially when used with K sparing diuretic
- cough and angioedema
What are the contraindications for ARNI?
- Pregancy (teratogenic)
- Concurrent use with CE inhibitor due to risk of angioedema
What are the effects of b-blockers?
- Decreased mortality
- decreased renin secretion
- decrease HR
- Decrease remodeling
When are B-blockers useful in HF?
-Only in the early stages! They are dangerous in end stage HF due to negative inotropic effect
What kind of drugs are sodium nitroprusside, isosorbide dinitrate, and hydralazine?
Vasodilators
Why are vasodilators effective in treating HF?
- Reduces preload and/or afterload
- Decrease damaging remodeling of the heart
What kind of drug is dobutamine?
Selective B1 agonist, has inotropic effects
When is dobutamine indicated?
Short term treatment of severe refractory HF
When is Dopamine indicated?
Short term treatment of severe refractory HF and an increase in BP is needed?
What does a low dose of dopamine do?
Activated D1 receptors in the kidney causing renal vasodilation
What does a moderate dose of dopamine do?
Activates B1 receptors in the heart and has an inotropic effect
What does a high dose of Dopamine do?
Activate Alpha receptors in the vessels causing vasoconstriction
What is the MOA of Digoxin?
-Inhibition of membrane sodium pump, leading to increased intracellular Na, decreased expulsion of intracellular Ca leading to increased SR Ca stores, leading to increased actin-myosin interaction, and ultimately increased contractility
What are the indications for Digoxin?
- Last agent used in HF
- Decreases HR in arrhythmias
What are the adverse effects of Digoxin?
- All glycosides are toxic
- Narrow margin of safety and can have toxicity at therapeutic doses
- Early sign of toxicity is GI upset
- CNS effects
- Arrhythmias
What is the treatment for minor and moderate Digoxin intoxication?
- Minor: stop digoxin
- Moderate: PO or IV potassium, stop digoxin
What is the treatment for severe digoxin intoxication?
Immunotherapy with Digitalis Immune Fab, along with potassium and stopping digoxin
