Time course, magnitude, and consistency of platelet inhibition by abciximab, tirofiban, or eptifibatide in patients with unstable angina pectoris undergoing percutaneous coronary intervention

Adjunctive platelet glycoprotein IIb/IIIa blockade during percutaneous coro nary intervention (PCI) reduces platelet mediated adverse ischemic outcomes , Although abciximab, eptifibatide, and tirofiban have received U.S. Food a nd Drug Administration approval for use, these agents differ in their pharm acodynamic profiles. Each of these agents has been compared in randomized t rials with placebo for patients undergoing PCI, but no randomized comparati ve studies of these agents have been performed. We compared ex vivo platele t function by both standard light transmission aggregometry and rapid plate let function assay during and after administration of abciximab, eptifibati de, or tirofiban in approved dose regimens on a randomized basis at the tim e of PCI in patients with unstable angina pectoris. A reduced intensity of platelet inhibition by light transmission aggregometry wets observed for ti rofiban compared with either eptifibatide or abciximab. In addition, the 30 -minute bolus strategy used for tirofiban was associated with delayed onset of maximal platelet inhibition relative to the initiation of bolus infusio n. Whether the trends in platelet function observed in this study will be t ranslated into differences in clinical outcomes awaits definition by larger scale randomized clinical trials comparing these platelet glycoprotein IIb /IIIa inhibitors. (C) 1999 by Excerpta Medica, Inc.