Eptifibatide and tirofiban: new preparations. Limited benefit

(1) Two antiplatelet drugs, eptifibatide and tirofiban, are licensed for the prevention of early myocardial infarction in patients with unstable angina or non Q-wave myocardial infarction. (2) These drugs appear to have a mechanism similar to that of abciximab. Abciximab reduced the incidence of myocardial infarction during the month following administration to patients with unstable angina who were scheduled for a percutaneous coronary procedure. (3) The clinical assessment files on eptifibatide and tirofiban are both centred on a large double-blind, placebo-controlled trial. (4) In patients with unstable angina or non Q-wave myocardial infarction, the PURSUIT trial, involving 10,948 patients, showed a lower incidence, at one month, of a combined end point (death or non fatal myocardial infarction) in patients on the eptifibatide + heparin + aspirin combination than in patients on the heparin + aspirin + placebo combination. A retrospective subgroup analysis raised the hypothesis that eptifibatide would be most beneficial in patients who had had coronary interventions. (5) In patients with unstable angina or non Q-wave myocardial infarction, the patients with unstable angina or non Q-wave myocardial infarction, the PRISM-PLUS trial, involving 1,915 patients, showed a reduction in the risk of myocardial infarction at 7 days in patients on the tirofiban + heparin + aspirin combination compared with those on the heparin +aspirin combination. Here too a retrospective subgroup analysis suggested that tirofiban would be most beneficial in patients who had had coronary intervention. (6) On the whole, these three antiplatelet drugs appear to benefit the same type of patient at high risk of myocardial infarction, but abciximab has been more thoroughly assessed than eptifibatide and tirofiban. Neither eptifibatide nor tirofiban (which were developed simultaneously) has been directly compared with abciximab. The value of antiplatelet drugs in patients treated with a low-molecular-weight heparin + aspirin combination is unknown. (7) These antiplatelet drugs carry a risk of haemorrhage and thrombocytopenia. On treatment cessation, coagulation function appears to normalise slightly more rapidly with eptifibatide (approximately 6 hours) and tirofiban (approximately 8 hours) than with abciximab (approximately 12 hours).