MOA of heparin?

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Multiple Choice

MOA of heparin?

Heparin works by binding to antithrombin III and greatly increasing its ability to inactivate clotting factors, especially thrombin (factor IIa) and factor Xa. By disabling thrombin, the conversion of fibrinogen to fibrin is blocked, which stops clot formation. This action is best described as neutralizing thrombin, since the key effect is reduced thrombin activity through ATIII. It’s also worth noting that unfractionated heparin inhibits both IIa and Xa, while low-molecular-weight heparins mainly inhibit Xa with less IIa effect. The other options don’t fit: vitamin K inhibition is warfarin’s mechanism, plasmin activation is for fibrinolytics like tPA, and calcium chelation is seen with agents such as EDTA/citrate.

Heparin works by binding to antithrombin III and greatly increasing its ability to inactivate clotting factors, especially thrombin (factor IIa) and factor Xa. By disabling thrombin, the conversion of fibrinogen to fibrin is blocked, which stops clot formation. This action is best described as neutralizing thrombin, since the key effect is reduced thrombin activity through ATIII. It’s also worth noting that unfractionated heparin inhibits both IIa and Xa, while low-molecular-weight heparins mainly inhibit Xa with less IIa effect. The other options don’t fit: vitamin K inhibition is warfarin’s mechanism, plasmin activation is for fibrinolytics like tPA, and calcium chelation is seen with agents such as EDTA/citrate.

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