Which Anticoagulant requires PTT/aPTT monitoring and has protamine sulfate as an antidote?

• A. Heparin
• B. Enoxaparin
• C. Warfarin
• D. Dabigatran

Answer: (A)

Unfractionated heparin has variable effects in different patients, so its anticoagulant effect is monitored with the aPTT (PTT) to keep therapy in a safe, effective range. Its specific antidote is protamine sulfate, which binds heparin and neutralizes its action. The other anticoagulants differ in how they’re monitored and reversed: low-molecular-weight heparins like enoxaparin are more predictable and usually don’t require routine aPTT monitoring, though protamine can partially reverse them; warfarin is monitored with the PT/INR and reversed with vitamin K or FFP, not protamine; and dabigatran is a direct thrombin inhibitor with its own reversal agent (idarucizumab) rather than protamine.