What is heparin?

What is heparin?

• A. Medication that inhibits clotting by activating antithrombin
• B. A vitamin K antagonist
• C. A fibrinolytic enzyme
• D. A platelet aggregation inhibitor

Answer: (A)

Heparin is an anticoagulant. It works by binding to and activating antithrombin III, which then more effectively inhibits key clotting enzymes, especially thrombin (factor IIa) and factor Xa. By blocking these factors, the formation of fibrin is reduced, so clots are prevented from growing and new clots are less likely to form. This rapid, direct action distinguishes it from other types of blood-thinning drugs: vitamin K antagonists (like warfarin) reduce the synthesis of several clotting factors; fibrinolytic enzymes (like tPA) dissolve existing clots; and platelet aggregation inhibitors (like aspirin) prevent platelets from sticking together. Heparin is typically given by injection and is monitored with tests like the aPTT to ensure proper anticoagulation; it can be reversed with protamine sulfate if needed.

Heparin is an anticoagulant. It works by binding to and activating antithrombin III, which then more effectively inhibits key clotting enzymes, especially thrombin (factor IIa) and factor Xa. By blocking these factors, the formation of fibrin is reduced, so clots are prevented from growing and new clots are less likely to form. This rapid, direct action distinguishes it from other types of blood-thinning drugs: vitamin K antagonists (like warfarin) reduce the synthesis of several clotting factors; fibrinolytic enzymes (like tPA) dissolve existing clots; and platelet aggregation inhibitors (like aspirin) prevent platelets from sticking together. Heparin is typically given by injection and is monitored with tests like the aPTT to ensure proper anticoagulation; it can be reversed with protamine sulfate if needed.