Antiplatelet agents and stroke prevention.

Aspirin (acetylsalicylic acid [ASA]) from 75 to 1,300 mg/day is an effective agent in the secondary prevention of stroke. Although no properly designed study has been performed, circumstantial evidence suggests that the favorable effect of ASA for stroke may be enhanced by higher doses. Ticlopidine is more effective than 1,300 mg/day of ASA, and clopidogrel is at least as effective as 325 mg of ASA a day; but, for various reasons, ASA at higher doses is still first choice by many. Three studies have shown no benefit of adding dipyridamole to ASA. A fourth did, but, in addition to other problems, the results are no better than those obtained by higher doses of ASA alone. ASA is an effective alternate to warfarin for patients with atrial fibrillation and contraindications to warfarin. Until a proper study has been performed, ASA is not recommended for the prevention of stroke in a low-risk asymptomatic elderly population.