Appearances of Premature Atrial and Ventricular Contractions After Switching From Brand Name to Generic Cibenzoline

In antiarrhythmic drugs, the therapeutic window is narrower than in other drugs. Brand name and generic drugs do not use same inactive ingredients binder substances. We report a 78-year-old male patient who had been treated for asymptomatic atrial fibrillation atrial/ventricular premature contractions. cibenzoline completely suppressed all arrhythmias. When medication was changed to drug, showed frequent palpitations After restarting brand-name arrhythmias were again. These results clear differences between brand specific patient. This first case describe diminished effectiveness of oral cibenzoline.