Itrazen 200 Itraconazole Fesoterodine Fumarate
MajorCYP3A4 Inhibitors: Doses of Fesotrex ER greater than 4 mg are not recommended in adult patients taking strong CYP3A4 inhibitors, such as ketoconazole, itraconazole, and clarithromycin.
These medicines can affect each other in a serious way. Do not start taking them together unless your doctor has said it is OK. If you already take both, do not stop either one on your own: speak to your doctor or pharmacist soon.