Article : Emergency Department Patients on Warfarin...

Emergency Department Patients on Warfarin Often Have Nontherapeutic INRs

In a study at a single ED, 30% of patients who presented on warfarin were given or prescribed medications that could affect anticoagulation response or bleeding risk.

Although warfarin therapy is typically safe, it can be associated with serious complications and interactions. In a retrospective chart review of 7195 patients who were treated and discharged from a single urban academic emergency department (ED) in California during a 3-month period, researchers assessed the prevalence and management of patients who were taking warfarin.

Overall, 111 patients (2%) reported currently taking warfarin, and 86% of these patients had indications for warfarin documented in the ED record. International normalized ratios (INRs) were measured during the visit in 79 patients (71%) taking warfarin; values were therapeutic in 51%, supratherapeutic in 9%, and subtherapeutic in 40%. Eight of 39 patients (21%) with nontherapeutic INRs (3 subtherapeutic and 5 supratherapeutic) received interventions or specific anticoagulation-related follow-up. Interventions included administration of vitamin K, administration of blood products, admission, withholding medication, altering dose of warfarin, and bridging with low-molecular-weight heparin. Medications that could affect anticoagulation response or bleeding risk were administered during the visit or prescribed on discharge to 33 patients (30%) on warfarin.


Meeker E et al. Emergency department management of patients on warfarin therapy. Ann Emerg Med 2011 Aug; 58:192.