Antiplatelet effects of abciximab, tirofiban and eptifibatide in patients undergoing coronary stenting

OBJECTIVES: We sought to investigate whether abciximab, tirofiban and eptifibatide achieve comparable antiplatelet effects with coronary stenting. BACKGROUND: The glycoprotein (GP) IIb/IIIa antagonists abciximab, tirofiban and eptifibatide differ in chemical structure, binding site and pharmacokinetics. METHODS: Sixty patients undergoing coronary stenting were randomly assigned to abciximab (bolus 0.25 mg/kg body weight, infusion 10 microg per min for 12 h), tirofiban (bolus 10 microg/kg, infusion 0.15 microg/kg per min for 72 h) or eptifibatide (bolus 180 microg/kg, infusion 2 microg/kg per min for 72 h). We took serial blood samples to analyze platelet function by using flow cytometry, turbidimetric aggregometry and the rapid platelet-function assay (RPFA). RESULTS: As assessed by RPFA, platelet aggregation after 2 h of infusion was reduced to 5.9 +/- 7.8% (mean +/- SD) of baseline by abciximab, to 5.0 +/- 5.4% by tirofiban and to 7.8 +/- 7.1% by eptifibatide (p = 0.42). Turbidimetric aggregometry with adenosine diphosphate stimulation yielded similar results, whereas percent inhibition of platelet aggregation after thrombin receptor stimulation was 45.8 +/- 16.8% with abciximab, 51.3 +/- 17.6% with tirofiban and 52.9 +/- 14.8% with eptifibatide (p = 0.37). Tirofiban and eptifibatide maintained their level of platelet inhibition during infusion. Flow cytometry revealed that the reduction in the monocyte-platelet interaction by abciximab, tirofiban and eptifibatide was not significantly different (20.0 +/- 21.9%, 23.8 +/- 18.2% and 21.0 +/- 19.8%, respectively; p = 0.87). CONCLUSIONS: Abciximab, tirofiban and eptifibatide, at currently recommended doses, achieved similar levels of inhibition of platelet aggregation and a similar reduction in the platelet-monocyte interaction.