Cardiac Drugs in Heart Failure Patients

1. Cardiac Drugs in Heart Failure Patients ZoulikhaZair 28th May 2013 N.B. some drugs overlap with treatment of hypertension….bonus revision wise!!!!

2. Question • What are the NICE guidelines for the pharmacological treatment of left ventricular heart failure?

3. Answer NICE guidelines for treatment of LV heart failure: • Diuretic - relief of congestive symptoms and fluid retention AND • First line: • ACE-inhibitors or • Beta-Blockers • Second line: • Add • Aldosterone antagonist • Angiotensin receptor antagonist • Hydralazine with nitrate • Third line: • Consider digoxin

4. Question • How do ACE-inhibitors work? • What are their side effects? • Name a commonly used ACE-inhibitors

5. Answer • ACE – inhibitor  vasodilator • Inhibits bradykinin breakdown (vasodilator) • Inhibits angiotensin converting enzyme  inhibits angiotensin II production • Side effects – dry cough, elevated K levels, birth defects, low blood pressure • Ramipril

6. Question • How do ARBs work? • What are their side effects? • Name a commonly used ARB

7. Answer • Inhibit action of Angiotensin II • Reduce vascular resistance • Restore tissue perfusion • Reduce afterload • Reduce aldosterone production • Natriuresis • Hypotension, renal impairment, hyperkalaemia, angioedema • Losartan

8. Question • How do beta-blockers work? • Name a selective beta1 blocker • What are the unwanted side effects?

9. Answer • Beta blockers reduce sympathetic stimulation of the heart by blocking beta-1 adrenergic receptors (Gs coupled cAMP increase) in the heart • Reduced sympathetic stimulation also reduces arterial pressure and decrease cardiac contractility • Dobutamine • Unwanted side effects – increase left ventricular dimensions, cold periphery and heart failure

10. Question • What is the mechanism of action for aldosterone antagonists? • What are the side effects of aldosterone? • Name an aldosterone antagonist

11. Answer • Blocks action of aldosterone at DCT • Increase Na+ and water excretion • K+-sparing diuretic • Especially effective combined with ACE-I / ARB • Hyperkalaemia, gynaecomastia (only in some), hypotension, hypernatraemia, GI upset, impotence • Eplerenone, spirnonolactone

12. Question • What is the mechanism of action for hydralazine? • What are the side effects of hydralazine?

13. Answer • Unknown mechanism of action • Dilates arteries & arterioles,  afterload • s/e: Tachycardia, GI upset, headache, lupus-like syndrome

14. Questions • How do nitrovasodilators work? • What are the unwanted side effects and problems?

15. Answers • Metabolised to NO  activate guanylatecyclase increase in cGMP fall in intracellular free calcium  vascular relaxation increase in venous capacitance  fall in central venous pressure  reduce preload  reduction in ventricular dimensions and cardiac output • Side effect – headache due to dilatation of intracranial arteries • Also problem with quickly developing tolerance that can lead to abnormal constriction of coronary arteries following withdrawal • Either inactivated enzyme that converts GTN to NO or desensitisation of blood vessels to NO

16. Vascular Drugs