Tolter Tolterodine Tartrate Clarithromycin
ModerateClarithromycin is a macrolide antibiotic, and it strongly blocks CYP3A4, the liver enzyme that breaks down tolterodine. When it is taken with tolterodine (Uritol), the body clears tolterodine more slowly, so more of it stays in the blood. To lower the chance of side effects, the recommended dose of Uritol in this case is 2 mg a day. The same advice applies to other strong CYP3A4 blockers, including ketoconazole, itraconazole, miconazole, erythromycin, cyclosporine and vinblastine.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.