Oral vitamin K-1: An option to reduce warfarin's activity

OBJECTIVE: TO report 6 patients taking oral vitamin K-1 (phytonadione) to reduce warfarin's activity. CASE SUMMARY: Six patient cases are summarized in which oral vitamin K, was used to reduce the international normalized ratio (INR) in patients at risk of bleeding. DISCUSSION: The use of oral vitamin K-1 to antagonize warfarin's effects is discussed, as well as the benefits of oral vitamin K-1 administration and the disadvantages of parenteral vitamin K-1 administration. In addition, an extensive literature review of the discovery and clinical development of warfarin and vitamin K-1 is described. CONCLUSIONS: In patients receiving warfarin therapy who have an increased WR and are at risk of bleeding, oral vitamin K-1 therapy may be safer, less painful, and more cost-effective than the traditional parenteral route of administration.