14. Patients being treated with drugs recognized as being strong inhibitors or inducers of the isoenzyme CYP3A (Rifabutin, Rifampicin, Clarithromycin, Ketoconazole, Itraconazoleonazole, Voriconazole, Ritonavir, Telithromycin) within the last 5 days prior to enrolment.