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Managing International Normalized Ratio Elevations With Direct Oral Anticoagulants in Emergency Settings SAEM PULSE | NOVEMBER-DECEMBER 2024
By Lisa Hayes, PharmD, on behalf of the SAEM Academic Emergency Medicine Pharmacist Interest Group
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Direct oral anticoagulants (DOACs) are increasingly used as first-line anticoagulants. The most common DOACs are the factor Xa inhibitors, including rivaroxaban, apixaban, and edoxaban. Dabigatran, a direct thrombin inhibitor, is also a DOAC but may be associated with an increased bleeding risk, primarily gastrointestinal, compared to the factor Xa inhibitors and warfarin. Factor Xa inhibitors are popular due to their reduced monitoring requirements and fewer drugdrug and drug-food interactions
compared to warfarin. Additionally, these agents do not require initial parenteral therapy, such as enoxaparin or heparin, which is often necessary when initiating warfarin. The international normalized ratio (INR) is traditionally utilized to monitor and adjust doses of warfarin. The INR was developed by the World Health Organization to standardize reporting of prothrombin time (PT). An INR goal of 2-3 is common for many patients on warfarin because this range correlates with the efficacy and
safety of warfarin. Generally, health care providers correlate elevations in INR with an increased extent of anticoagulation and a heightened risk of bleeding. With the increased use of factor Xa inhibitors, many patients on DOACs may inadvertently have an INR ordered and reported, necessitating interpretation. INR elevation in patients taking oral factor Xa inhibitors or direct thrombin inhibitors is common and has been documented in both in vitro and observational studies. Ofek and colleagues reported on the incidence