Concomitant use of dronedarone with dabigatran in patients with atrial fibrillation in clinical practice

Dronedarone is a strong P-glycoprotein inhibitor with a potential to increase bioavailability of dabigatran. We sought to measure and report plasma concentrations of dabigatran in patients with atrial fibrillation (AF) on concomitant dronedarone treatment.

A cohort of 33 patients (mean age 64 years, 16 men) concomitantly treated with dabigatran at a dose of 110 mg twice a day (bid) and dronedarone at a dose of 400mg bid at the discretion of the patient's cardiologist were followed prospectively.

Median trough plasma concentration of dabigatran at one week and one month after the concomitant treatment start was 102.0 (range 8-251) ng/ml and 84 (range 27-302) ng/ml respectively. Median treatment length was 13 (range 1-21) months. There was one major bleeding event (2,8% per patient-year) and no thrombotic events during a total of 35.5 patient-years.

Median trough plasma concentration of dabigatran in our study was observed to be similar to median trough plasma concentration of dabigatran at a dose of 150 mg bid without concomitant dronedarone in earlier studies with low reported rate of bleeding and thrombosis. Since concomitant treatment offers potential benefits to patients with AF, larger future trials that might refute the current contraindication are warranted.