Pharmacological Treatments for Heart Failure Flashcards
Give 10 types of drugs used in heart failure
- Diuretics
- ACE inhibitors
- Aldosterone antagonists
- Beta blockers
- Phosphodiesterase III inhibitors
- Digoxin
- Dopamine
- Dobutamine
- Adrenaline
- Nitroprusside
What is the function of diuretics in heart failure?
Reduce preload
How do diuretics reduce preload?
Through increased excretion of sodium and water
Give 3 ACE inhibitors that are used in heart failure?
- Enalapril
- Captopril
- Lisinopril
What is the mechanism of action of ACE inhibitors?
Prevent conversion of angiotensin I to angiotensin II
What is the result of ACE inhibitors preventing the conversion of angiotensin I to angiotensin II?
It increases plasma renin levels and reduces aldosterone secretion
What is the purpose of ACE inhibitors in heart failure?
Reduce preload and afterload
How do ACE inhibitors reduce preload?
Venous dilatation
How do ACE inhibitors reduce afterload?
Decreasing peripheral vascular resistance
Why do ACE inhibitors reduce peripheral vascular resistance?
Because angiotensin II is a potent vasoconstrictor, and ACE inhibitors prevent it’s production
Give an example of an aldosterone antagonist used in heart failure?
Spironolactone
What is the mechanism of action of aldosterone antagonists?
Competes with aldosterone for receptor sites in distal renal tubule, increasing water excretion whilst retaining potassium and hydrogen ions
Give an example of a beta-blocker used in heart failure?
Atenolol
What is the purpose of beta blockers in heart failure?
- Increases stroke volume
- Decreases contractility and left ventricular size
What is the advantage of long-term beta blockers in heart failure?
It blocks the damaging effects of overactive sympathetic activity
Give an example of a phosphodiesterase III inhibitor used in heart failure?
Milrinone
What is the effect of phosphodiesterase III inhibitors?
Positive inotrope and vasodilator with little chronotopic activity
Alos has lusitropic activity
What does chronotropic mean?
Increases heart rate
What does lusitropic mean?
Causes myocardial relaxation
What is the mechanism of action of digoxin?
Inhibits Na/K-ATPase, which increases intracellular Na and causes a secondary increase in intracellular Ca
What class of drug is digoxin?
Cardiac glycoside
What is the effect of digoxin on the heart?
It increases the force of contraction
What is dopamine?
A catecholamine
What is the mechanism of action of digoxin?
It stimulates ß1, alpha-1 and dopaminergic receptors in a dose dependent fashion
