Clopidogrel functions by irreversibly inhibiting a receptor called P2Y12, an adenosine diphosphate (ADP) receptor located on platelet cell membranes. This receptor is important in the process of platelet activation and of fibrin cross-linking in secondary hemostasis.
The blockage of this receptor inhibits platelet aggregation by blocking activation of the glycoprotein IIb/IIIa pathway. The IIb/IIIa complex functions as a receptor, mainly for fibrinogen, in the hemostatic process. Ultimately, the fibrin cross-linking is inhibited, leading to the desired antithrombotic (anticoagulant) activity of the medication.