Harr Hematology Practice Test

Prasugrel is an antiplatelet medication that specifically inhibits ADP (adenosine diphosphate) mediated platelet aggregation. It works by irreversibly binding to the P2Y12 subtype of the ADP receptor on platelets, preventing activation and aggregation that would normally lead to clot formation. This mechanism is crucial in preventing thrombotic events, particularly in patients with acute coronary syndrome or those undergoing percutaneous coronary interventions.

Heparin and warfarin, while they are anticoagulants used to prevent thrombosis, do so through different mechanisms that do not directly involve inhibition of platelet aggregation via ADP. Heparin primarily works by enhancing the activity of antithrombin III, which inhibits thrombin and factor Xa, leading to decreased fibrin formation. Warfarin acts as a vitamin K antagonist, influencing the production of clotting factors dependent on vitamin K but does not target ADP receptors or platelet function directly.

Aspirin, on the other hand, inhibits platelet aggregation but does so by irreversibly acetylating cyclooxygenase-1 (COX-1), thereby decreasing the formation of thromboxane A2, which is another key molecule involved in platelet activation. While aspirin is