Vitamin K Dosing to Reverse Warfarin Based on INR, Route of Administration, and Home Warfarin Dose in the Acute/Critical Care Setting

Abstract

Vitamin K dose, route, and initial INR influence subsequent INR values. INR reduction is similar for intravenous vitamin K doses of 2 mg or greater. Preadministration of FFP does not alter INR values at 48 hours or more after vitamin K administration.

Management of Supratherapeutic International Normalized Ratio without Bleeding after Warfarin Use: An Evaluation of Vitamin K Administration (SUPRA-WAR-K Study)

“…17 The current data also suggest that different doses and routes of vitamin K have similar efficacy and safety. These findings differ from those in a retrospective chart review by Tsu and others, 8 who concluded that IV administration of vitamin K was associated with a more rapid decrease in INR than oral administration in a population of hospitalized patients. However, the patients who received oral vitamin K had higher mean baseline INR than those who received IV vitamin K (5.67 versus 5.09), and the mean decreases in INR at 24 h after the intervention were similar for the IV and oral routes (3.55 and 3.53, respectively).…”

“…However, the patients who received oral vitamin K had higher mean baseline INR than those who received IV vitamin K (5.67 versus 5.09), and the mean decreases in INR at 24 h after the intervention were similar for the IV and oral routes (3.55 and 3.53, respectively). 8 Consistent with our results, the incidence and duration of bridging anticoagulation, rate of thromboembolism, and 30-day mortality rate were not significantly different between the IV and oral administration groups. 8 However, for reasons that the authors stated were unclear to them, hospital length of stay was significantly longer among patients who received vitamin K by the IV route than among those who received vitamin K by the oral route (13.54 versus 10.16 days, p = 0.02).…”

“…5 The evidence for vitamin K in hospitalized patients is limited to a small number of studies with populations that combined critical care and non-critical care patients or inpatients and outpatients. 7,8 To our knowledge, there have been no published studies examining the efficacy and safety of vitamin K solely in hospitalized non-critical care patients, nor have there been subgroup analyses focusing on this population in existing studies. Compared with outpatients, acutely ill inpatients are at an increased risk of coagulation abnormalities.…”

Pharmacologic interventions for reversing the effects of oral anticoagulants

“…route causes a reduction in the INR within the first six to eight hours after administration. 4 However, the reduction in INR achieved after a 24-to 48-hour period is similar with the i.v. and oral routes.…”

“…phytonadione dose. 4 These shortacting agents have a faster onset of action than i.v. phytonadione because of the time required for formation of vitamin K-dependent clotting factors with phytonadione.…”