Dose of aspirin in the treatment and prevention of cardiovascular disease: current and future directions.

In meta-analyses of randomized trials of aspirin among patients with prior occlusive vascular disease events (secondary prevention), doses from 75 mg to more than 1500 mg daily provide similar benefits on myocardial infarction, stroke, and cardiovascular death. In acute myocardial infarction and during acute occlusive stroke, a loading dose of 162.5 to 325 mg is necessary to achieve a rapid clinical antithrombotic effect. In primary prevention trials, predominantly among men, aspirin (75 mg daily to 325 mg on alternate days) reduced the risk of a first myocardial infarction. In a large-scale trial in women, aspirin (100 mg on alternate days) reduced risk of a first stroke. In subgroup analyses of women older than age 65, aspirin significantly reduced first myocardial infarction and ischemic stroke. Direct comparisons of higher doses may yield additional cardiovascular benefits. At present, daily doses of 75 to 325 mg aspirin are sufficient for long-term treatment and prevention of cardiovascular disease.