A 60-year-old man with symptomatic peripheral arterial disease and intermittent claudication is considered for cilostazol. His echocardiogram shows an ejection fraction of 35 percent with NYHA class II heart failure. Why should cilostazol be avoided in this patient?
- A It causes profound bradycardia through vagal stimulation
- B It precipitates digitalis toxicity by displacing digoxin from albumin
- C PDE3 inhibition raises intracellular cAMP in cardiac myocytes and has been associated with increased mortality in heart failure ✓
- D It causes coronary vasospasm through adenosine receptor blockade
Correct answer: C. PDE3 inhibition raises intracellular cAMP in cardiac myocytes and has been associated with increased mortality in heart failure
Explanation
Cilostazol is a phosphodiesterase-3 inhibitor that increases cAMP in platelets and vascular smooth muscle, producing antiplatelet and vasodilator effects useful in claudication. PDE3 inhibitors such as milrinone increase myocardial cAMP and contractility but have been linked to increased mortality in chronic heart failure, so cilostazol is contraindicated in patients with heart failure of any severity. Its common adverse effects are headache, palpitations and diarrhoea.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
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