Oral vs. IV Vitamin K for Reversing Excessive Anticoagulation

Data from nonrandomized and uncontrolled studies suggest that oral vitamin K works somewhat slower than, but is nearly as effective as, less commonly used IV vitamin K for reversing excessive warfarin anticoagulation. Researchers in Israel randomized 61 patients with excessive anticoagulation (INR range, 6.1-19.4; mean, 9.2), but without major bleeding, to receive IV or oral vitamin K. Patients with moderately high INRs (6-10) received either 0.5 mg intravenously or 2.5 mg orally; patients with very high INRs (>10) received 1 mg or 5 mg, respectively.

Among patients with moderately high baseline INRs, IV vitamin K reversed the excessive anticoagulation more rapidly than did oral vitamin K: At 4 hours, mean INRs were approximately 5 with IV v…