The FDA has approved a combination of aspirin and the antiplatelet agent dipyridamole (Aggrenox; Boehringer Ingelheim Pharmaceuticals Inc, Richfield, Conn) to reduce the risk of stroke for patients who have already had transient ischemic attacks or completed ischemic strokes due to blood clots in the brain. Each hard gelatin capsule contains 200 mg of dipyridamole in an extended-release form and 25 mg of aspirin as an immediate-release sugar-coated tablet.
The pivotal clinical trial of the drug was a double-blind, placebo-controlled, 24-month study that included 6602 patients who had an ischemic stroke (76%) or transient ischemic attack (24%) within 3 months before entering the trial. The study compared use of the combination pill with use of each active ingredient alone and with placebo. These comparisons showed that the combination reduced the risk of stroke by 36.8% compared with placebo, 22.1% compared with aspirin alone, and 24.4% compared with dipyridamole alone. The combination also reduced the risk of stroke or death by 24.2% compared with placebo, 12.1% compared with aspirin alone, and 10.3% compared with extended-release dipyridamole alone.
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