Warfarin toxicity in the emergency department: Recommendations for management

Abstract

Objective: To examine patients who presented to a hospital emergency department with evidence of warfarin toxicity, and to review the available published literature to determine what guidelines are available for management of this problem. Method: A retrospective analysis of all adult patients who presented to The Geelong Hospital Emergency Department between 1 January 1996 and 30 June 1998 with international normalized ratio > 6 due to warfarin toxicity. Results: A total of 84 patients with international normalized ratio > 6 were included in the study. The average age was 68.3 years. Fifty‐three per cent were women. The international normalized ratio was between 6 and 10 in 33 patients (39%), and greater than 10 in 51 patients (61%). Major bleeding occurred in 16.7% of patients, minor bleeding in 17.8%. Sixty‐five per cent had no bleeding. Seven patients died, four of those with bleeding. Patients with an international normalized ratio > 10 were more likely to receive fresh frozen plasma (77.6%vs 28.6%; P < 0.001) and in greater amounts (3.0 units vs 0.8 units; P < 0.001) than those with an international normalized ratio of 6–10. There were also more episodes of major bleeding, although not significant. Patients with major bleeding were older (mean 75.4 years vs 67.5 years; P = 0.04), more likely to be admitted (P = 0.046), were more often given fresh frozen plasma (P = 0.003) and in greater amounts (3.28 units vs 2.0 units; P = 0.02). Conclusion: Warfarin toxicity is a common problem, and variation in management is not surprising considering the lack of consensus in the literature on this topic. Current recommendations are summarized and a simple flowchart for management of this problem is provided.

Fatal intoxications by acenocoumarol, phenprocoumon and warfarin: Method validation in blood using the total error approach

“…Consequently, administration of these products has to be made with respect of a narrow therapeutic index, is delicate and needs regular medical control to avoid risks of haemorrhage [1,2]. Indeed, the therapeutic overdose can be at the origin of particularly serious hemorrhagic accidents, causing death in case of late medical intervention [3].…”

CYP2C9 Mutation Affecting the Individual Variability of Warfarin Dose Requirement

“…Cruickshank et al5 reported that severe hemorrhage, at about 1.0-3.0% and light hemorrhage at about 4.8-9.5%, occur in warfarin-dosed patients each year. Landelfeld and Beyth reported that the risk of hemorrhage in the group of patients who received warfarin treatment was 0.6-9.6%, which is five times higher than that in a group of those without warfarin administration 6…”

Novel Hemostatic Agents: A Focus on Recombinant Factor VIIa and Factor XIII

“…Overdoses of vitamin K antagonists, accidental or otherwise, and destabilization of the INR are not uncommon, and account for a significant number of unnecessary deaths. 36 The standard approach for such patients depends on whether they present with active bleeding or whether their INR is too high. For the non-bleeding patient whose INR is supratherapeutic, temporary discontinuation of the oral anticoagulant may suffice.…”