Summary The thienopyridines, ticlopidine and clopidogrel, are antiplatelet drugs. They are prodrugs and are metabolised in the liver to active metabolites that are nonโcompetitive antagonists of the platelet adenosine diphosphate receptor, P2Y~12~. Inhibition of platelet aggregation by these drugs is delayed until 24โ48โh after administration, with maximal inhibition achieved after 3โ5โdays. Recovery of platelet function after drug withdrawal is slow (7โ14โdays). Ticlopidine and clopidogrel are effective in preventing atherothrombotic events in cardiovascular, cerebrovascular and peripheral vascular disease. Gastrointestinal side effects and skin rashes are common. However, neutropenia and thrombotic thrombocytopenic purpura are significant and sometimes fatal adverse effects of ticlopidine. Clopidogrel appears to offer several advantages over ticlopidine: a more rapid onset of action and a lower incidence of neutropenia and thrombotic thrombocytopenic purpura.A combination of clopidogrel and aspirin has become standard for antithrombotic therapy in cardiovascular disease. The anaesthetic considerations of patients taking the thienopyridine compounds are discussed.