Use of antiplatelet drugs in secondary prevention in older persons with atherothrombotic disease.

Unless there are contraindications to the use of aspirin, aspirin should be used in treating patients with acute myocardial infarction (MI) and continued indefinitely to reduce vascular death, nonfatal MI, and nonfatal stroke. Clopidogrel added to aspirin has been shown to be beneficial in the treatment of patients with acute ST-elevation MI. Patients with unstable angina or non-ST-elevation MI should be treated with aspirin plus clopidogrel for at least 9 months to reduce vascular death, nonfatal MI, and nonfatal stroke. Patients with prior MI should be treated indefinitely with aspirin and with clopidogrel if aspirin is contraindicated. Patients with ischemic stroke should be treated with either aspirin or clopidogrel indefinitely. Extended release dipyridamole plus low dose aspirin has been shown to be more efficacious than low dose aspirin in only one large study, and is associated with an insignificant increase in nonfatal MI and vascular death over low dose aspirin alone. Clopidogrel is significantly more effective than aspirin in reducing vascular death, nonfatal MI, and nonfatal stroke in patients with peripheral arterial disease.