Analysis of trials evaluating combinations of acetylsalicylic acid and dipyridamole in the secondary prevention of stroke

Background: Stroke is one of the leading causes of morbidity and mortality in the United States. Patients who suffer a cerebrovascular event are at hi gh risk of a recurrence, and secondary prevention is crucial to reducing th e burden of cerebrovascular disease. Acetylsalicylic acid (ASA, aspirin) is an established method of stroke prophylaxis. Objective: This review investigates whether the addition of dipyridamole to ASA further reduces the risk of stroke recurrence. Methods: To identify clinical trials of the use of combinations of ASA and dipyridamole in the prevention of recurrent stroke in patients who have suf fered a first stroke or transient ischemic attack, the English-language lit erature was searched from 1966 through May 2001 using the MEDLINE, Internat ional Pharmaceutical Abstracts, EMBASE, and BIOSIS databases. The search te rms used were dipyridamole, aspirin, acetylsalicylic acid, ischemic stroke, and cerebrovascular disorders. Conclusions: Of the 5 published studies, 3 earlier studies detected no diff erences in outcome when dipyridamole was added to ASA therapy for stroke pr ophylaxis. Two more recent trials found that the addition of dipyridamole t o ASA therapy provided further reduction in the risk of secondary cerebrova scular events compared with placebo and with ASA alone. Further studies are needed to confirm long-term benefit.