We report five patients (four women, one man; mean age 74 years, range 55-87) taking terodiline who had torsades de pointes ventricular tachycardia associated with prolongation of the QT interval. The QT interval was normal before the introduction of terodiline in three patients and returned to normal after terodiline withdrawal in four. Atrioventricular conduction disturbance or bradycardia were evident in all patients. Terodiline should be prescribed with caution to elderly patients.