Vitamin K to reverse excessive anticoagulation: A review of the literature

We conducted an extensive literature review to evaluate the appropriate use , route, and dose of vitamin K to reverse excessive anticoagulation. Issues such as sample size, study design, different patient populations, and vari ous study end points confounded results. Of 18 studies published, 8 enrolle d 229 patients to evaluate parenteral. vitamin K administration. Nine studi es with 288 patients evaluated oral administration, and only 2 retrospectiv e studies (280 patients) compared routes of administration. Reductions in i nternational normalized ratios at 24 hours ranged from 21-42%, 47-86%, 25-6 7%, and 40-75% for temporary warfarin discontinuation alone, and intravenou s, subcutaneous, and oral routes of vitamin K administration, respectively. Methodologically weak studies and indeterminate results plague interpretat ion of the literature on vitamin K. Tn general, results of this review supp ort current guidelines for reversing excessive warfarin anticoagulation. Ho wever, it is important to realize that the quality of literature on which t hese recommendations are based is poor and that optimal dose and route of v itamin K administration remain unclear. Large, well-designed, randomized, c ontrolled trials are necessary to define optimum management strategies for excessively anticoagulated patients.