Prasugrel (Efient) is a potent, selective and irreversible inhibitor of adenosine diphosphate (ADP)-mediated platelet aggregation that is indicated for the prevention of atherothrombotic events in patients with acute coronary syndromes (ACS) [comprising unstable angina pectoris/non-ST-segment-elevation myocardial infarction (unstable angina/NSTEMI) and ST-segment-elevation myocardial infarction (STEMI)] undergoing percutaneous coronary intervention (PCI). Oral prasugrel provides rapid, potent inhibition of platelet aggregation and is an effective antiplatelet agent for the management of patients with ACS who are undergoing PCI. In these patients, prasugrel was associated with a significantly lower incidence of ischaemic events than clopidogrel, and was particularly effective in specific subgroups of patients, such as those with diabetes mellitus. However, the efficacy of prasugrel was offset by a higher risk of bleeding than clopidogrel, with patients aged > or =75 years, those weighing <60 kg and those with a history of stroke or transient ischaemic attack at the greatest risk. A lower dose of prasugrel in patients aged > or =75 years and those weighing <60 kg may help to minimize the bleeding risk, although more data are needed to establish this; prasugrel is contraindicated in patients with a history of stroke or transient ischaemic attack. Thus, prasugrel provides a new option for the management of patients with ACS who are undergoing PCI; the risk-benefit ratio should be carefully assessed before intensive antiplatelet therapy with prasugrel is initiated.