Effectiveness and safety of a management protocol to correct over-anticoagulation with oral vitamin K: a retrospective study of 1,043 cases

Background Timely reversal of excessive anticoagulation is important in preventing bleeding complications. The use of vitamin K in correcting over-anticoagulation is widely accepted to be superior to discontinuation of therapy but its effectiveness and safety in large scale cohort studies has not been assessed. Methods According to our protocol, 2 mg of oral vitamin K in addition to omitting the day’s dose of warfarin, were administered to all patients presenting INR levels ≥5.0 and below 10.0; the INR values were checked 20 h after vitamin K administration. The rate of decay of INR, bleeding and thromboembolic complications at presentation and the following 30 days, as well as resistance to warfarin were assessed. Results Of the 1,611 events, 1,043 (878 patients) met the selection criteria. The median (interquartile range) INR was 6.64 (6.12–7.52) at presentation ( day zero ) and fell to a median (interquartile range) INR of 2.72 (2.18–3.52, P