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
What do lower doses of dopamine cause?
Vasodilation in renal and splanchnic beds
What receptors does dopamine act on at lower doses?
Dopaminergic
What receptors does dopamine act on at mid-range doses?
Beta-receptors
What is the action of dopamine at mid-range doses?
Increase heart rate and contractility
What receptor do high doses of dopamine act on?
Alpha-receptors
What is the action of dopamine at high doses?
Increases systemic vascular resistance and increases blood pressure
What class of drug is dobutamine?
Sympathomimetic
Does dobutamine have stronger alpha or beta action?
Beta
What does dobutamine produce when acting on ß1 receptors?
Increases contractility
What action does dobutamine produce when acting on ß2 receptors?
Systemic vasodilation
What is the mechanism of action of adrenaline?
Alpha agonist and beta2 agonist
What is adrenalines action when acting on alpha receptors?
Increases peripheral vascular resistance
What is adrenalines action when acting on beta2 receptors?
Positive chronotrope and inotrope
What are the actions of nitroprusside?
- Vasodilation
- Increases inotropic activity of the heart
How does nitroprusside cause vasodilation?
By relaxing vascular smooth muscle
