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Effect of vitamin K administration on rate of warfarin reversal
Author(s) -
Polito Nick B.,
Kanouse Eric,
Jones Courtney M.C.,
McCann Molly,
Refaai Majed A.,
Acquisto Nicole M.
Publication year - 2019
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.15146
Subject(s) - medicine , confidence interval , warfarin , hazard ratio , vitamin , vitamin k , gastroenterology , anesthesia , atrial fibrillation
BACKGROUND Vitamin K is reported to begin reversing warfarin within 6 to 12 hours, but this may occur sooner. We sought to determine the rate of international normalized ratio (INR) reversal following vitamin K and relationships with dose, route, and baseline INR. METHODS We evaluated adult patients receiving vitamin K monotherapy for warfarin reversal. Post–vitamin K INRs through 48 hours were collected. Relationships between vitamin K dose and route and baseline INR on rate of reversal and complete reversal (INR < 1.5) were evaluated. Assessment was performed graphically using scatter plots with a line of best fit and a counting process model to determine variables associated with achieving complete reversal. RESULTS A total of 469 post–vitamin K INRs from 235 patients were included. Time to first INR follow‐up after vitamin K administration averaged 10.5 ± 4.2 hours. A significant decrease was detected in INR values in comparison to the baseline INR (3.0 ± 1.9 vs. 4.7 ± 2.2; p < 0.01). Rapid and steady INR change began immediately after vitamin K administration (0–4 hr). A high vitamin K dose and intravenous route were associated with rapid INR change and complete reversal (Vitamin K 10 mg [hazard ratio, 2.4; 95% confidence interval, 1.4–4.2] and IV route [hazard ratio, 1.8; 95% confidence interval, 1.3–2.6]); however, overall complete reversal at 24 and 48 hours was low (14.5% and 41.7%, respectively). Higher baseline INR was associated with rapid INR change and lower baseline INR with complete reversal. CONCLUSION Vitamin K alone starts to reverse warfarin immediately. High vitamin K doses and intravenous route are associated with faster INR reversal. Baseline INR also influences rate of correction and frequency of achieving complete reversal.