Assessing the Impact of in-Hospital Formulary Policies on the Prescription Patterns of Direct Oral Anticoagulants (DOACs)

Prescribing direct oral anticoagulants (DOACs) with off-label dosage and administration is discouraged due to concerns about their effectiveness and safety. Consequently, our hospital pharmacist established a formulary with physicians for oral anticoagulants. Our study aimed to assess the adherence to this formulary by investigating the rate of appropriate DOAC prescribing. We included patients who were newly prescribed or continued on DOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) at our hospital. We calculated the percentage of patients prescribed the correct dosage and administration according to the package insert and compared this across three time periods: pre-intervention (period A; April-September 2019), post-intervention phase 1 (period B; August 2021-January 2022), and post-intervention phase 2 (period C; November 2022-April 2023). We also examined the number of inquiries and consultation requests made by hospital pharmacists regarding DOAC dosage and administration. A total of 782 patients were surveyed (191 in period A, 263 in period B, and 328 in period C). The appropriate prescribing rates for DOACs were 79.1% in period A, 84.4% in period B, and 86.6% in period C. The proportion of cases where hospital pharmacists questioned or consulted doctors about DOAC dosage and administration was 3.7% in period A, 6.1% in period B, and 10.1% in period C. These findings indicate that active intervention by hospital pharmacists using the formulary regarding oral anticoagulant formularies may promote appropriate DOAC use.