What is the purpose of administering Vitamin K to a patient with a high INR on warfarin?

• A. To enhance anticoagulation
• B. To reverse anticoagulation
• C. To treat infection
• D. To reduce blood pressure

Answer: (B)

When warfarin makes the blood too thin, seen as a high INR, the goal is to reverse that anticoagulant effect. Vitamin K supplies the body with the cofactor needed to synthesize the vitamin K–dependent clotting factors II, VII, IX, and X, which warfarin inhibits. By restoring these factors, vitamin K brings the INR back toward the therapeutic range and reduces the risk of bleeding. The approach (oral for milder cases, intravenous for urgent reversal, sometimes with additional products if bleeding is present) depends on how high the INR is and whether there’s active bleeding. This option is not about increasing anticoagulation, treating infection, or lowering blood pressure.