A prospective randomized trial comparing the recovery of platelet function after loading dose administration of prasugrel or clopidogrel

Prasugrel results in greater platelet inhibition compared to clopidogrel which may prolong the time to platelet P2Y12 receptor function recovery following drug cessation after loading dose (LD) administration. This randomized study assessed the time to recovery of platelet function in patients with coronary artery disease after a LD of prasugrel or clopidogrel. Enrolled patients (n=21) received either prasugrel (30mg or 60mg) or clopidogrel (600mg) in preparation for coronary angiography. Platelet function was assessed by the Verify Now P2Y12 assay, Multiplate and LTA at baseline and over time (1, 3, 5, 7, 9, and 11 days) post-LD treatment. Recovery of platelet function was defined as occurring on the first day that P2Y12 reaction units were ≤60 below pre-drug values and remained in this range. The relationship between platelet inhibition at 24h post-LD to time of recovery was also evaluated. Recovery of platelet function occurred from days 3-7 for clopidogrel-treated subjects, by day 7 for patients treated with prasugrel 30mg and from days 7-9 for patients treated with prasugrel 60mg. Time for platelet function to return to baseline was independent of treatment assignment, reflecting instead the extent of platelet inhibition at 24h post-LD (correlation coefficient=0.81, p<0.001), which was greater following a prasugrel LD. Conclusions: Prasugrel-treated subjects require a longer time for recovery compared with clopidogrel due to greater post-LD platelet inhibition. Platelet function testing after cessation of P2Y12 receptor blockers may prove useful to guide the timing of surgical procedures (clinicaltrials.gov identifier: NCT01107899).