Does Ketoconazole Interact with Fesoterodine Fumarate?
CDI records a major classification for Ketoconazole and Fesoterodine Fumarate. The stored summary is: Strong CYP3A4 inhibitor causing approximately doubling of fesoterodine active metabolite exposure. Doses greater than 4 mg not recommended in adults. The mechanism involves cyp3a4 inhibition. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.
Evidence status
A current label comparison is not yet available for this record. The summary and severity are stored CDI information; they have not been independently validated on this page against the exact product label.
Confirm the medicine, formulation, route, and applicable warning with your pharmacist or prescriber. Independent clinical review has not been recorded.
- Stored CDI classification
- Major
- Ketoconazole Class
- Azole Antifungal
- Management
- Confirm exact products with your pharmacist
- Data Source
- U.S. FDA via OpenFDA
Recorded Mechanism
CYP3A4 inhibition
What To Tell Your Doctor or Pharmacist
If you are taking Ketoconazole and your doctor is considering prescribing Fesoterodine Fumarate (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider