Romanian Society of Pharmaceutical Sciences

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FACTORS ASSOCIATED WITH INAPPROPRIATE APIXABAN DOSING PERSISTENCE IN NONVALVULAR ATRIAL FIBRILLATION PATIENTS AT A UNIVERSITY TEACHING HOSPITAL IN RIYADH, SAUDI ARABIA

AHMED A. ALANAZI 1*, MOHAMMED S. ALZAYED 2, ABDULAZIZ M. ALHOSSAN 3, KHALID A. ALAMER 1, ABDULAZIZ G. ALQAHTANI 4, RAGHAD S. ALSAIF 5, BASHAYR M. ALSUWAYNI 4, LUBNA A. ALMASUOOD 6, RAND A. ALDAKHEELI 6, HAYAM A. ALTUWAIJRI 7, MOHAMMED B. ALOTAIBI 4

1 Department of Pharmacy Practice, College of Pharmacy, Imam Abdulrahman bin Faisal University, Dammam 34221, Saudi Arabia
2 Hospital Director of King Salman Specialist Hospital, Hail Health Cluster, Hail, Saudi Arabia
3 Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
4 Pharmacy Services, King Khalid Medical City, Riyadh 11451, Saudi Arabia
5 Clinical Pharmacy Department, King Saud Medical City, Riyadh, Saudi Arabia
6 Pharmacy Services, Dr. Soliman Fakeeh Hospital, Riyadh, Saudi Arabia
7 College of Pharmacy, Qassim University, Al-Qaseem 52379, Saudi Arabia

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Direct oral anticoagulants (DOACs), including apixaban, have addressed limitations associated with warfarin use for anticoagulation in patients with nonvalvular atrial fibrillation (NVAF). While data suggest that apixaban is safe, its safety depends on appropriate dosing. This single-centre retrospective cohort study aimed to evaluate patient-related factors associated with the persistence of inappropriate apixaban prescribing and to describe bleeding events during follow-up. The records from King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia, were reviewed between January 2020 and December 2022. Among 367 patient records examined, 227 (61.85%) received the appropriate apixaban dose, while 140 (38.15%) were inappropriately dosed, with the vast majority being underdosed (132 patients, 94.3%). Inappropriate dosing persisted in 108 patients (29.4%) during follow-up. Female sex, age (≥ 75 years), overweight/obesity and antiplatelet use were identified as key contributors to persistent inappropriate dosing, though none reached statistical significance. Although these findings were not statistically significant, they have important clinical implications, as inappropriate dosing may compromise anticoagulation efficacy. Seventeen patients (4.6%) experienced bleeding events, with most occurring during periods of underdosing or appropriate dosing. These results underscore the importance of continued clinician education and decision support tools to optimise anticoagulant therapy and improve outcomes in patients with NVAF.