An idiosyncratic reaction to clopidogrel.

Clopidogrel is an irreversible antiplatelet agent belonging to the thienopyridine group that acts to antagonize the adenosine diphosphate P2Y12 receptor on platelets. It thus inhibits the activation of platelet glycoprotein GPIIb/IIIa complex, which is essential for fibrinogen—platelet complex formation. Clopidogrel has widely replaced ticlopidine because of a much better clinical safety profile. Clopidogrel is a prodrug that requires hepatic activation to exert its antiplatelet effect. Hepatotoxicity with use of clopidogrel is a rare but clinically significant phenomenon. We report a case of clopidogrel-induced hepatotoxicity in an elderly white woman.