Mark A. Crowther, MD, MSc; James D. Douketis, MD; Terri Schnurr, RN; Luigi Steidl, MD; Valentina Mera, MD; Carolina Ultori, MD; Achille Venco, MD; Walter Ageno, MD
Grant Support: Dr. Crowther holds a Research Scholarship from the Canadian Institutes for Health Research. Dr. Douketis holds a Research Scholarship from the Heart and Stroke Foundation of Canada.
Requests for Single Reprints: Mark A. Crowther, MD, MSc, St. Joseph's Hospital, Room L208, 50 Charlton Avenue East, Hamilton, Ontario L8N 4A6, Canada; e-mail, firstname.lastname@example.org.
Potential Conflicts of Interest: None disclosed.
Current Author Addresses: Drs. Crowther and Douketis and Ms. Schnurr: St. Joseph's Hospital, 50 Charlton Avenue East, Hamilton, Ontario L8N 4A6, Canada.
Drs. Steidl, Mera, Ultori, Venco, and Ageno: Ospedale di Circolo, Medicina Interna, Viale Borri 57, 21100 Varese, Italy.
Author Contributions: Conception and design: M.A. Crowther, J.D. Douketis, T. Schnurr.
Analysis and interpretation of the data: M.A. Crowther, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
Drafting of the article: M.A. Crowther, J.D. Douketis.
Critical revision of the article for important intellectual content: M.A. Crowther, J.D. Douketis, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
Final approval of the article: M.A. Crowther, J.D. Douketis, V. Mera, C. Ultori, A. Venco, W. Ageno.
Provision of study materials or patients: M.A. Crowther, J.D. Douketis, T. Schnurr, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
Statistical expertise: M.A. Crowther.
Administrative, technical, or logistic support: M.A. Crowther, T. Schnurr.
Collection and assembly of data: M.A. Crowther, J.D. Douketis, T. Schnurr, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
Excessive anticoagulation due to warfarin use is associated with hemorrhage. Subcutaneously administered vitamin K has not been evaluated for the treatment of warfarin-associated coagulopathy, yet it is widely used.
To show that oral vitamin K is more effective than subcutaneous vitamin K in the treatment of warfarin-associated coagulopathy.
Randomized, controlled trial.
Two teaching hospitals.
Patients with an international normalized ratio (INR) between 4.5 and 10.0.
Warfarin therapy was withheld, and 1 mg of vitamin K was given orally or subcutaneously.
The primary outcome measure was the INR on the day after administration of vitamin K. Secondary outcome measures were hemorrhage and thrombosis during a 1-month follow-up period.
15 of 26 patients receiving oral vitamin K and 6 of 25 patients receiving subcutaneous vitamin K had therapeutic INRs on the day after study drug administration (P = 0.015; odds ratio, 4.32 [95% CI, 1.13 to 17.44]).
Oral vitamin K lowers INR more rapidly than subcutaneous vitamin K in asymptomatic patients who have supratherapeutic INR values while receiving warfarin.
Crowther MA, Douketis JD, Schnurr T, Steidl L, Mera V, Ultori C, et al. Oral Vitamin K Lowers the International Normalized Ratio More Rapidly Than Subcutaneous Vitamin K in the Treatment of Warfarin-Associated Coagulopathy: A Randomized, Controlled Trial. Ann Intern Med. ;137:251–254. doi: 10.7326/0003-4819-137-4-200208200-00009
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Published: Ann Intern Med. 2002;137(4):251-254.
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