10. Concomitant medication interfering with study medication intake due to potential interactions (all psychotropic medication including analgetics and muscle relaxants, hypericum derivatives; antihypertensives; anti-arrhythmic agents; antibiotics; cisaprid; anti-malaria drugs; diuretics; imidazole antifungals; cumarin derivatives; antihistaminics; calcium channel blockers; medications that enlarge the QT interval or may lead to hypokalemia)