Hypersensitivity to the active substance or to any of the excipients listed in Description. Severe renal impairment (creatinine clearance < 30 ml/min) (see Dosage & Administration and Pharmacology: Pharmacokinetics under Actions). Moderate or severe hepatic impairment (see Dosage & Administration and Pharmacology: Pharmacokinetics under Actions). Concomitant administration of potent CYP3A4 inhibitors (e.g. itraconazole, ketoconazole, voriconazol, posaconazol, HIV protease inhibitors, clarithromycin, telithromycin, nefazodone) (see Dosage & Administration and Interactions). Concomitant administration of Class Ia (e.g. quinidine) or Class III (e.g. dofetilide, sotalol) antiarrhythmics other than amiodarone.