Drugs that inhibit platelet function are widely used to decrease the risk of occlusive arterial events in patients with atherosclerosis. There are three families of anti-platelet agents with proven clinical efficacy: (1) cyclooxygenase inhibitors, such as aspirin; (2) adenosine diphosphate receptor antagonists, such as the thienopyridine compounds ticlopidine and clopidogrel; and (3) glycoprotein IIb/IIIa antagonists. All these drugs are used during coronary interventions and in the medical management of acute coronary syndromes, while only aspirin and thienopyridine compounds are used in the long-term prevention of cardiovascular and cerebrovascular events in patients at risk. Despite the good risk-to-benefit ratio of anti-platelet agents, the risk of severe bleeding complications, including cerebral haemorrhage, is slightly increased, albeit to a much lesser extent than that associated with the use of other antithrombotic drugs, such as anticoagulants or thromobolytic agents. In addition, it must be noted that the increased incidence of haemorrhagic stroke is usually outweighed by a significant decrease in the incidence of ischaemic strokes. The combination of aspirin and vitamin K antagonists may be associated with the heightened risk of cerebral haemorrhage, compared to treatment with either drug alone.
