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 μg per min for 12 h), tirofiban (bolus 10 μg/kg, infusion 0.15 μg/kg per min for 72 h) or eptifibatide (bolus 180 μg/kg, infusion 2 μg/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.