IV Vitamin K and Warfarin

Q: One dose of intravenous (IV) Vitamin K antagonizes the effects of warfarin for how many days?

Answer: About one week

A high dose of Vitamin K (= 10 mg) produces rapid reversal; however, overcorrection and warfarin resistance complicate therapy. A 10-mg dose of vitamin K antagonizes warfarin's effects on clotting factor synthesis for 7 days. Low doses (0.5-2.5 mg) reverse anticoagulation within 24 hours (taking a little longer) with less risk of overcorrection or resistance to reinstitution of therapy.

Most guidelines for warfarin reversal recommend stringent use in this regard.

#hematology

References:

1. Rivosecchi RM, Garavaglia J, Kane-Gill SL. An evaluation of intravenous vitamin k for warfarin reversal: are guideline recommendations being followed? Hosp Pharm. 2015 Jan;50(1):18-24. doi: 10.1310/hpj5001-18. PMID: 25684796; PMCID: PMC4321424.

2. Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ, Svensson PJ, Veenstra DL, Crowther M, Guyatt GH. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb;141(2 Suppl):e152S-e184S. doi: 10.1378/chest.11-2295. PMID: 22315259; PMCID: PMC3278055.

3. Polito NB, Kanouse E, Jones CMC, McCann M, Refaai MA, Acquisto NM. Effect of vitamin K administration on rate of warfarin reversal. Transfusion. 2019 Apr;59(4):1202-1208. doi: 10.1111/trf.15146. Epub 2019 Feb 4. PMID: 30714620.