Update on selecting and adjusting antiplatelet therapy for prevention of noncardiogenic, recurrent ischemic stroke

Antiplatelet therapy is a cornerstone of secondary prevention in patients with prior stroke or transient ischemic attack. Recent clinical trials and subanalyses of previous trials have influenced the selection of antiplatelet agents. Clinical decisions regarding the use of antiplatelet therapies have also been affected by recent advancements in our understanding of drug action, metabolism and drug-drug interactions. Aspirin has an established role in secondary prevention of stroke, although some patients are unable to tolerate it and others are resistant to its antiplatelet effects. Platelet function tests are available, but their routine use is not yet established. Clopidogrel and the combination of aspirin with extended-release dipyridamole both have established roles in secondary stroke prevention, but the optimal choice of agent is not always clear. Clinical trials of head-to-head comparisons will be discussed, as well as trials of combination therapies. In addition, several issues have surfaced recently impinging on the use of clopidogrel, especially relating to variable metabolism of the drug to its active metabolite and to interactions with proton pump inhibitors. The clinical implications of these issues will be discussed with respect to the secondary prevention of stroke.