Chapter 24: Heart Failure Drugs Flashcards
What are the drug therapies for heart failure?
- ACE inhibitors
- Angiotensin II receptor blockers
- Beta blockers
- aldosterone antagonists
- B-type natriuretic peptides
- phosphodiesterase inhibitors
- cardiac glycoside (digoxin)
Aldosterone antagonist
indicated for severe CHF
Spironolactone
potassium-sparing diuretic that has been shown to reduce CHF symptoms
What drugs are considered aldosterone antagonists?
spironolactone and eplerenone
What are the miscellaneous drugs to treat heart failure?
- hydralazine/isosorbide dinitrate
- dobutamine
hydralazine/isosorbide dinitrate
first drug approved for a specific ethnic group, namely african americans
dobutamine
- beta1-selective vasoactive adrenergic drug
- structurally similar to dopamine
B-Type Natriuretic Peptides includes
Nesiritide (Natrecor)
nesiritide (natrecor)
used in the intensive care setting as a final effort to treat severe, life-threatening heart failure, often in combination with several other cardiostimulatory medications
Mechanism of action for B-Type Natriuretic Peptides
- effects include diuresis (urinary fluid loss), natriuresis (urinary sodium loss) and vasodilation
- vasodilating effects on both arteries and veins
- indirectly increases cardiac output
- suppresses renin-angiotensin system
Phosphodiesterase Inhibitors
work by inhibiting the enzyme phosphodiesterase
Use of phosphodiesterase inhibitors results in
positive inotropic response and vasodilation
Name a phosphodiesterase inhibitor
milrinone (primacor)
What are the indications of phosphodiesterase inhibitors?
- short-term management of heart failure
- given when patient does not respond to treatment with digoxin, diuretics and/or vasodilators
- American Heart Associations and American College of Cardiology advise against long term infusions
Adverse Effects of the Phosphodiesterase inhibitor, Milrinone
- dysrhythmia
- hypotension
- angina
- hypokalemia
- tremor
- thrombocytopenia
Cardiac Glycosides
- from digitalis plant, foxglove
- for heart failure and control ventricular response to atrial fibrillation or flutter
- prototype is digoxin
What is the mechanism of action for cardiac glycosides?
- increase myocardial contractility
- change electrical conduction properties of the heart: decrease rate of electrical conduction, prolong the refractory period (area between SA node and AV node)
What are the drug effects of cardiac glycosides?
- positive inotropic effect
- negative chronotropic effect
- negative dromotropic effect
positive inotropic effect
increased force of myocardial contraction (without an increase in oxygen consumption)
Negative chronotropic effect
reduces heart rate
Negative dromotropic effect
decreases electrical conduction of heart
What are indications for cardiac glycosides?
- heart failure
- supraventricular dysrhythmias: atrial fibrillation and atrial flutter
What are the cardiac glycosides?
digoxin and lanoxin
Cardiac Glycosides: Digoxin and Lanoxin
- very narrow therapeutic window
- drug levels must be monitored: 0.5-2 ng/mL
- electrolyte levels must be monitored
What do low potassium levels do to the cardiac glycosides: digoxin and lanoxin?
low potassium levels increase its toxicity
What are the adverse effects of cardiac glycosides?
- CV
- CNS
- Eyes
- GI
What are the adverse effects on the cardiovascular system due to cardiac glycosides?
dysrhythmias, including bradycardia or tachycardia
What are the adverse effects on the CNS due to cardiac glycosides?
headaches, fatigue, malaise, confusion, convulsions
What are the adverse effects on the eyes due to cardiac glycosides?
colored vision (seeing green, yellow, purple), halo vision, flickering lights
What are the adverse effects on the GI system due to cardiac glycosides?
Anorexia, nausea, vomiting and diarrhea
Digoxin Toxicity
- hyperkalemia (serum potassium greater than 5 mEq/L) in a digitalis toxic patient
- life-threatening cardiac dysrhythmias
- life-threatening digoxin overdose
What is the antidote for digoxin toxicity?
digoxin immune Fab
What are conditions that predispose digoxin toxicity?
- hypokalemia, use of a pacemaker, liver disease, hypercalcemia
- dysrhythmias, hypothyroid, respiratory, or renal disease, advanced age
Nursing Diagnosis
discuss nursing diagnosis and patient-centered care pg 383-387
inotropic
drugs that influence the force of muscular contractions, particularly contractions of the heart muscle
chronotropic
drugs that influence the rate of the heartbeat
dromotropic
drugs that influence the conduction of electrical impulses within the tissues
