The antiplatelet drug prasugrel is one of the new generations of thienopyridines, drugs that inhibit the platelet P2Y(12) receptor. It is becoming clear that there is variability in individual responses to antiplatelet agents such as clopidogrel, which may limit their efficacy and widespread utility. A number of controversies remain, such as varied definitions of "nonresponders" to antiplatelet therapy, the optimal means of assessing platelet function, and the potential capacity of in vivo platelet function studies to predict future clinical events. Prasugrel provides more rapid and consistent platelet inhibition than does clopidogrel, yet its clinical utility is under scrutiny. We aim to review the available data evaluating the efficacy and safety of this novel antiplatelet agent.