Direct oral anticoagulant therapy and drug interactions in patients with atrial fibrillation

Background. Drug-drug interactions (DDIs) are one potential cause of adverse drug events. Very little has been done to study the relationship between potential DDIs in patients (p) with atrial fibrilla-tion (AF) on direct oral anticoagulants (DOACs). Many anticoagulants are elimi-nated by the kidneys, so they can accumu-late if their dose is not adapted to the kid-ney function. DDI is one particular type of drug error that can result in adverse drug events (ADEs) in exposed patients and was the aim of this study.

Materials and Methods. A total of 50 pa-tients with AF on DOACs (25 patients on dabigatran and 25 on rivaroxaban) with normal, mildly or moderately decreased (estimated GFR > 30 mlmin-11.73m2) renal function were included (age 69±7 years, 26M/24F, body mass index (BMI) 35.4±5.1 kg/m2, duration of hyperten-sion 11±5 years, duration of AF 5±2 years, eGFR 58±23 mlmin-11.73m2 (was calcu-lated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula). 

Results. The 12-month administration of DOACs caused a nonsignificant de-crease of eGFR (declined from 58±23 mlmin-11.73m2 to 56±17 mlmin-11.73m2 (p=0.01). All patients have the right dose of DOACs according to eGFR. Patients with AF and DOACs on more than 3 different drugs (20%) such as statins, verapamil and amiodarone were more prone to AE. Conclusion. DDIs are one of the most important problems in every day prac-tice. Coadministration of statins with da-bigatran worsens clinical outcomes and a similar interaction might be seen with ve-rapamil and amiodarone. Patients need to be on the right drug/right dose given the kidney function they have, with special care on DDIs.

drug-drug interactions, direct oral anticoagulants, renal function

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