A critical appraisal of ticlopidine, a new antiplatelet agent. Effectiveness and clinical indications for prophylaxis of atherosclerotic events.

BACKGROUND: Recommendations are broadening for the prophylaxis of atherosclerotic disorders, but aspirin is the only widely used agent. Ticlopidine hydrochloride, a new antiplatelet medication, has recently been approved for prescription in North America. We reviewed the major clinical trials of ticlopidine and derived guidelines for its use. METHODS: Studies of ticlopidine were sought through MEDLINE for 1980 to 1990 and through bibliographies of retrieved articles. All published, randomized trials of ticlopidine were appraised if they reported major morbidity and mortality as primary end points. All eligible studies were formally reviewed by an expert panel according to published principles for critical appraisal of the medical literature. Both benefits and risks were quantified. RESULTS: Four randomized trials reported major clinical end points. In these, ticlopidine was more effective than placebo for preventing recurrences after completed stroke; was more effective than aspirin for patients with transient ischemic attacks and partial strokes; and reduced vascular death and nonfatal myocardial infarction in an open trial among patients with unstable angina. For patients with intermittent claudication ticlopidine, was not significantly better than placebo for preventing myocardial infarction or stroke. Side effects were more common with ticlopidine than with aspirin or placebo. CONCLUSIONS: Ticlopidine should be prescribed in place of aspirin for stroke prophylaxis or unstable angina if the patient is unable to tolerate aspirin. Ticlopidine may also benefit patients who experience new ischemic events while taking aspirin or, probably, patients with peripheral vascular disease. A complete blood cell count should be performed every 2 weeks during the first 3 months of therapy to check for leukopenia.