GPIIb/IIIa Inhibitors

  • GPIIb/IIIa inhibitors are a class of platelet inhibitors which function by binding to and blocking GPIIb/IIIa receptors on the platelet surface. As described in Platelet Plugging, GPIIb/IIIa is a receptor on the platelet surface that undergoes a conformational change upon activation of the platelet allowing it to bind plasma fibrinogen. Because multiple GPIIb/IIIa molecules from different platelets can bind the same fibrinogen molecule, this facilitates platelet aggregation at sites of vascular injury. By preventing the GPIIb/IIIa molecule from interacting with fibrinogen these drugs consequently inhibit the process of platelet aggregation. GPIIb/IIIa inhibitors are structurally divergent with the prototype, Abciximab, being a monoclonal Fab Fragment whereas Eptifibatide and Tirofiban are small peptides.
Adverse Effects
  • The major adverse effect of these drugs is predictably bleeding
  • Abciximab has been associated with thrombocytopenia. For interests sake, this likely occurs as an immune reaction to a novel epitope formed by abciximab adsorbed onto platelets.
Member Drugs
  • Abciximab
  • Eptifibatide
  • Tirofiban