Pharmacist Interventions Regarding the Appropriateness of Apixaban, Rivaroxaban, Dabigatran, and Warfarin in a University-Affiliated Outpatient Clinic

Abstract

Background: Direct oral anticoagulants (DOACs) have become available recently as an alternative to warfarin in appropriate patients. Few studies have been conducted that evaluate pharmacist-managed services for the management of the DOACs. Objective: To review the appropriateness of DOAC therapy and warfarin therapy in adult patients in a university-affiliated outpatient clinic and the need for further monitoring of these agents. Methods: A retrospective chart review was conducted of patients receiving a DOAC or warfarin therapy. Indication, dose, duration, age, weight, adherence, drug interactions, bleeding risk/history, renal function, and hepatic function were evaluated for DOACs and warfarin. If prescribed warfarin, international normalized ratio readings were also obtained. The pharmacists made verbal recommendations to primary care prescribers regarding findings, and changes to therapy were reviewed and documented. Results: A total of 175 patient charts were reviewed (49% DOACs, 51% warfarin). Twenty-five percent of prescribed DOACs should have been avoided due to inappropriate indication or renal function. The majority of these were switched to warfarin after discussion with the primary care provider. Of patients prescribed DOACs, 22% had a history of poor adherence to therapy and half of these were switched to warfarin. An additional 24% of prescribed DOACs were inappropriate due to incorrect dosing, major drug interactions, and/or renal dosing; however, these medications could be appropriate if adjustments are made. Nineteen percent of patients on warfarin therapy would be a candidate for DOAC therapy. Conclusion: Although there were limitations to this analysis, the results demonstrate that additional intervention is needed to improve appropriate prescribing and monitoring of the DOACs. Pharmacists can meet this need by providing medication reviews of novel anticoagulants and educating physicians.