2. The chronic use of any drug known to interact with praziquantel, or artesunate or lumefantrine metabolism (e.g. phenytoin, carbamazepine, phenobarbital, primidon, dexamethasone, rifampicin, cimetidine, flecainide, metoprolol, imipramine, amitriptyline, clomipramine, class I and III anti-arrythmics, antipsychotics, antidepressants, macrolides, fluoroquinolones, imidazole- and triazole antimycotics, antihistamines) Because lumefantrine may cause extension of QT-time, chronic use of drugs with effect on QT interval are excluded from the study.