Impact of aspirin dosing on the effects of P2Y12 inhibition in patients with acute coronary syndromes

The discovery of the antiplatelet effect of low-dose aspirin led to the hugely successful strategy of dual antiplatelet therapy in patients with acute coronary syndromes (ACS). Increasing the dose of aspirin beyond 75-100 mg has never been shown to offer additional efficacy in ACS patients but could possibly increase the risk of bleeding. In the Platelet Inhibition and Patients Outcome (PLATO) study, higher doses of aspirin appeared to neutralise the additional benefit of the potent P2Y12 inhibitor ticagrelor compared to clopidogrel (Circulation 124: 544-554, 2011). However, higher doses of aspirin have not been shown to have an adverse interaction with the potent P2Y12 inhibition provided by prasugrel and double-dose clopidogrel (Journal of the American College of Cardiology, 2013, in press; N Engl J Med 363: 930-942, 2010). This potentially suggests that the mechanism for this interaction is not related to the inhibition of platelet P2Y12 receptors or could simply be a chance finding.