Ticagrelor Versus Clopidogrel in Acute Coronary Syndromes

Abstract

The thienopyridine clopidogrel, which irreversibly blocks the adenosine diphosphate (ADP) receptor P2Y12 on platelets, has become an essential component of therapy in patients with acute coronary syndromes, because it significantly improves the outcomes. However, clopidogrel has at least three drawbacks: delayed onset of action, large inter individual variability in platelet response, and irreversibility of its inhibitory effect on platelets. The U.S. Food and Drug Administration approved the Ticagrelor on July 20, 2011.Ticagrelor is an anti-platelet drug which is orally active and binds reversibly to P2Y12 receptor antagonist that blocks ADP-induced platelet aggregation. It was specifically designed to address the limitations of the available antiplatelet agents while maintaining comparable or better antiplatelet effects. It does not require metabolic activation and demonstrates greater platelet inhibition, a faster offset of action and comparable bleeding risk compared to clopidogrel. Theoretically, this property might be expected to result in less bleeding than with an irreversible compound that binds to the platelet for its lifespan. The Safety and efficacy of ticagrelor compared with clopidogrel in ACS patient has been recently evaluated by the PLATelet inhibition and patient Outcomes (PLATO) trial. The pivotal PLATO trial in patients with an acute coronary syndrome demonstrated improved cardiovascular outcomes, including a reduction in myocardial infarctions and vascular events using ticagrelor as compared to clopidogrel with comparable rates of major bleeds.