Fesoterodine Fumarate has 11 known drug interactions based on U.S. FDA drug labeling data. 3 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Clarithromycin, Itraconazole, Ketoconazole. Patients taking Fesoterodine Fumarate should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 11
- Major
- 3
- Moderate
- 7
- Minor
- 1
Major (3)
- Fesoterodine Fumarate + Clarithromycin— Strong CYP3A4 inhibitor. Doses of fesoterodine greater than 4 mg not recommended in adult patients taking this drug.
- Fesoterodine Fumarate + Itraconazole— Strong CYP3A4 inhibitor. Doses of fesoterodine greater than 4 mg not recommended in adult patients taking this drug.
- Fesoterodine Fumarate + Ketoconazole— Strong CYP3A4 inhibitor causing approximately doubling of fesoterodine active metabolite exposure. Doses greater than 4 …
Moderate (7)
- Fesoterodine Fumarate + Carbamazepine— CYP3A4 inducer. No dosing adjustments recommended in the presence of this drug.
- Fesoterodine Fumarate + Diltiazem— Moderate CYP3A4 inhibitor. No dosing adjustments recommended in the presence of this drug.
- Fesoterodine Fumarate + Erythromycin— No dosing adjustments are recommended in the presence of moderate CYP3A4 inhibitors (e.g., erythromycin, fluconazole, di…
- Fesoterodine Fumarate + Fluconazole— Following blockade of CYP3A4 by coadministration of the moderate CYP3A4 inhibitor fluconazole 200 mg twice a day for 2 d…
- Fesoterodine Fumarate + Grapefruit Juice— Moderate CYP3A4 inhibitor. No dosing adjustments recommended in the presence of this substance.
- Fesoterodine Fumarate + Rifampin— CYP3A4 inducer causing approximately 70% decrease in active metabolite Cmax and 75% decrease in AUC. No dosing adjustmen…
- Fesoterodine Fumarate + Verapamil— Moderate CYP3A4 inhibitor. No dosing adjustments recommended in the presence of this drug.
Minor (1)
- Fesoterodine Fumarate + Cimetidine— Weak CYP3A4 inhibitor. Effect not expected to exceed that of moderate inhibitors.