Clinical evaluation of adverse effects during bepridil administration for atrial fibrillation and flutter

Bepridil hydrochloride (Bpd) has attracted attention as an effective drug for atrial fibrillation (AF) and atrial flutter (AFL). However, serious adverse effects, including torsade de pointes (Tdp), have been reported.

Adverse effects of Bpd requiring discontinuation of treatment were evaluated. Bpd was administered to 459 patients (361 males, 63+/-12 years old) comprising 378 AF and 81 AFL cases. Mean left ventricular ejection fraction and atrial dimension (LAD) were 66+/-11% and 40+/-6 mm, respectively. Adverse effects were observed in 19 patients (4%) during an average follow-up of 20 months. There was marked QT prolongation greater than 0.55 s in 13 patients, bradycardia less than 40 beats/min in 6 patients, dizziness and general fatigue in 1 patient each. In 4 of 13 patients with QT prolongation, Tdp occurred. The major triggering factors of Tdp were hypokalemia and sudden decrease in heart rate. There were no differences in the clinical backgrounds of the patients with and without Tdp other than LAD and age, which were larger and older in the patients with Tdp.

Careful observation of serum potassium concentration and the ECG should always be done during Bpd administration, particularly in elderly patients.