To the Editor.
—Ticlopidine hydrochloride (Ticlid, Roche Laboratories, Nutley, NJ) is an antiplatelet drug that has been marketed in the United States since October 1991. Based on reports since then, the labeling of ticlopidine has been changed. Ticlopidine is indicated to reduce the risk of thrombotic stroke in patients who have experienced stroke precursors or had a completed stroke, and it should be reserved for patients who are intolerant of aspirin therapy indicated to prevent stroke. The product labeling as approved in 1991 included a boxed warning that states neutropenia occurred in 2.4% and severe neutropenia and/or agranulocytosis occurred in 0.8% of stroke patients who received ticlopidine in premarketing clinical trials. Reports in the medical literature suggest that ticlopidine may also be associated with aplastic anemia and thrombotic thrombocytopenic purpura.1-3 In a preliminary worldwide search of adverse hematologic events associated with ticlopidine through 1994, a total of 645 cases