Conclusion
Our patient had a prolonged elevation of her INR for 10 days despite daily subcutaneous injections of vitamin K. Due to the vitamin's short half-life, she could have received 10 mg orally or subcutaneously every 8 hours initially and her INR may have been within the normal range within 6 days. However, the prolonged INR may have been due to coingestion of warfarin and acetaminophen and to administration of antibiotics during hospitalization. No published randomized, placebo-controlled studies have evaluated the warfarin-acetaminophen interaction. In our patient, acetaminophen may have contributed to decreased metabolism of warfarin, thereby reducing its clearance.
Address reprint requests to Duane Bates, Pharmacy Department, Foothills Medical Centre, 1403 29th Street NW, Calgary, AB, Canada T2N 2T9.
Pharmacotherapy. 2000;20(10) © 2000 Pharmacotherapy Publications
Copyright © 1999, Pharmacotherapy Publications, Inc., All rights reserved.
Cite this: Phytonadione Therapy in a Multiple-Drug Overdose Involving Warfarin - Medscape - Oct 01, 2000.
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