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
- Mark A. Crowther, MD, MSc;
- James D. Douketis, MD;
- Terri Schnurr, RN;
- Luigi Steidl, MD;
- Valentina Mera, MD;
- Carolina Ultori, MD;
- Achille Venco, MD; and
- Walter Ageno, MD
Abstract
Background: 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.
Objective: To show that oral vitamin K is more effective than subcutaneous vitamin K in the treatment of warfarin-associated coagulopathy.
Design: Randomized, controlled trial.
Setting: Two teaching hospitals.
Patients: Patients with an international normalized ratio (INR) between 4.5 and 10.0.
Intervention: Warfarin therapy was withheld, and 1 mg of vitamin K was given orally or subcutaneously.
Measurements: 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.
Results: 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]).
Conclusion: Oral vitamin K lowers INR more rapidly than subcutaneous vitamin K in asymptomatic patients who have supratherapeutic INR values while receiving warfarin.
Article and Author Information
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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.
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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, crowthrm{at}mcmaster.ca.
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Potential Conflicts of Interest: None disclosed.
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Current Author Addresses: Drs. Crowther and Douketis and Ms. Schnurr: St. Joseph's Hospital, 50 Charlton Avenue East, Hamilton, Ontario L8N 4A6, Canada.
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Drs. Steidl, Mera, Ultori, Venco, and Ageno: Ospedale di Circolo, Medicina Interna, Viale Borri 57, 21100 Varese, Italy.
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Author Contributions: Conception and design: M.A. Crowther, J.D. Douketis, T. Schnurr.
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Analysis and interpretation of the data: M.A. Crowther, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
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Drafting of the article: M.A. Crowther, J.D. Douketis.
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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.
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Final approval of the article: M.A. Crowther, J.D. Douketis, V. Mera, C. Ultori, A. Venco, W. Ageno.
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Provision of study materials or patients: M.A. Crowther, J.D. Douketis, T. Schnurr, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
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Statistical expertise: M.A. Crowther.
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Administrative, technical, or logistic support: M.A. Crowther, T. Schnurr.
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Collection and assembly of data: M.A. Crowther, J.D. Douketis, T. Schnurr, L. Steidl, V. Mera, C. Ultori, A. Venco, W. Ageno.
- Copyright ©2004 by the American College of Physicians
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