A client on heparin begins to bleed; which is the antidote for heparin?

• A. Vitamin K
• B. Protamine sulfate
• C. Aminocaproic acid
• D. Vitamin C

Answer: (B)

Protamine sulfate is the antidote for heparin because it binds to heparin to form a stable complex, neutralizing its anticoagulant effect quickly when given IV. This reversal is essential for stopping or preventing bleeding in someone actively bleeding on heparin. Heparin works by enhancing antithrombin III to inhibit thrombin and factor Xa, so neutralizing heparin restores the blood’s ability to form clots.

Dosing is given IV slowly, and the amount depends on how much heparin was given and when. Monitor the patient and watch for possible reactions to protamine, such as hypotension or anaphylaxis.

Other agents listed don’t reverse heparin: vitamin K reverses warfarin, aminocaproic acid is used for certain bleeding disorders related to fibrinolysis, and vitamin C has no role in reversing anticoagulation.