Novel antiplatelet strategies in acute coronary syndromes.

Antiplatelet therapies for the treatment of acute coronary syndromes (ACS) act to interrupt various pathways of platelet activation. Clopidogrel, an established thienopyridine antiplatelet medication, inhibits adenosine diphosphate (ADP)-induced platelet aggregation to a modest degree and with wide variability in platelet response. Accumulating data suggest that a 600-mg loading dose of clopidogrel may help overcome the suboptimal response to the standard 300-mg dose seen in some patients. Prasugrel is a third-generation investigational thienopyridine that demonstrates more potent inhibition of platelet aggregation and more consistent platelet response compared with standard- and high-dose clopidogrel. A large clinical trial showed prasugrel to be superior to standard-dose clopidogrel in reducing ischemic events in patients with ACS scheduled for percutaneous coronary intervention, although prasugrel was associated with a significantly higher risk of major bleeding events. Other investigational antiplatelet agents also display more potent and consistent inhibition of platelet aggregation than is seen with clopidogrel. These include AZD6140, a reversible ADP receptor blocker; cangrelor, a rapidly acting intravenous ADP receptor blocker; and the thrombin receptor antagonist SCH 530348.