Which medication inhibits platelets?

Which medication inhibits platelets?

• A. Heparin
• B. Aspirin
• C. TPA
• D. Vitamin K

Answer: (B)

Inhibiting platelets means stopping them from sticking together to form a plug at the injury site. The drug that does this best in practice is aspirin. It irreversibly blocks the enzyme COX-1 in platelets, which drops the production of thromboxane A2, a key signal that promotes platelet aggregation and vasoconstriction. Since platelets can’t make new COX-1, this effect lasts for the platelets’ entire lifespan (about 7–10 days) until new platelets are produced. That’s why aspirin is categorized as an antiplatelet agent. The other options work differently: heparin speeds up antithrombin III to prevent the formation of fibrin in the coagulation cascade; tissue plasminogen activator dissolves clots by converting plasminogen to plasmin; vitamin K is needed to synthesize several clotting factors in the liver. These do not primarily inhibit platelet function.

Inhibiting platelets means stopping them from sticking together to form a plug at the injury site. The drug that does this best in practice is aspirin. It irreversibly blocks the enzyme COX-1 in platelets, which drops the production of thromboxane A2, a key signal that promotes platelet aggregation and vasoconstriction. Since platelets can’t make new COX-1, this effect lasts for the platelets’ entire lifespan (about 7–10 days) until new platelets are produced. That’s why aspirin is categorized as an antiplatelet agent.

The other options work differently: heparin speeds up antithrombin III to prevent the formation of fibrin in the coagulation cascade; tissue plasminogen activator dissolves clots by converting plasminogen to plasmin; vitamin K is needed to synthesize several clotting factors in the liver. These do not primarily inhibit platelet function.