What is the antidote for warfarin?

What is the antidote for warfarin?

• A. Vitamin K
• B. Protamine sulfate
• C. Fresh frozen plasma
• D. Calcium

Answer: (A)

Warfarin inhibits the enzyme that recycles vitamin K, preventing production of the vitamin K–dependent clotting factors II, VII, IX, and X. Giving vitamin K replenishes stores and allows the liver to resume making active clotting factors, reversing the anticoagulant effect. This is the standard antidote. For nonurgent reversal, oral vitamin K works gradually over hours to days. In urgent or active bleeding, intravenous vitamin K reverses faster but is often paired with fresh frozen plasma or prothrombin complex concentrate to provide immediate clotting factors while vitamin K takes effect. Protamine sulfate reverses heparin, and calcium—though important in various clotting contexts—does not reverse warfarin.

Warfarin inhibits the enzyme that recycles vitamin K, preventing production of the vitamin K–dependent clotting factors II, VII, IX, and X. Giving vitamin K replenishes stores and allows the liver to resume making active clotting factors, reversing the anticoagulant effect. This is the standard antidote. For nonurgent reversal, oral vitamin K works gradually over hours to days. In urgent or active bleeding, intravenous vitamin K reverses faster but is often paired with fresh frozen plasma or prothrombin complex concentrate to provide immediate clotting factors while vitamin K takes effect. Protamine sulfate reverses heparin, and calcium—though important in various clotting contexts—does not reverse warfarin.