Clopidogrel and Thrombotic Thrombocytopenic Purpura

To the Editor: Clopidogrel is indicated for the reduction of atherosclerotic events (myocardial infarction, stroke, and death from vascular causes) in patients with atherosclerosis documented by recent stroke, recent myocardial infarction, or established peripheral arterial disease. This indication is based on the results of a clinical trial, involving 19,185 patients, in which clopidogrel was compared with aspirin in patients at risk for ischemic events. The study's steering committee estimated that clopidogrel would prevent about 24 major clinical events for every 1000 patients treated for one year. 1 Clopidogrel was approved by the Food and Drug Administration (FDA) in November 1997 and . . .