Clopidogrel is a thienopyridine antiplatelet agent that functions as a prodrug. It is converted in the liver by cytochrome P450 enzymes into an active metabolite. This active metabolite then irreversibly binds to the P2Y12 receptor, a specific chemoreceptor for adenosine diphosphate (ADP), on the surface of platelets. The binding of ADP to the P2Y12 receptor is a crucial step in platelet activation and aggregation. By blocking this receptor, clopidogrel prevents ADP-mediated activation of the glycoprotein IIb/IIIa receptor complex, thereby inhibiting platelet aggregation.