Itraconazole and Fesoterodine Interaction
Drug interaction information between Itraconazole and Fesoterodine.
Itraconazole and Fesoterodine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Itraconazole and Fesoterodine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Itraconazole prevents the body from getting rid of fesoterodine, leading to higher amounts of the drug in your blood.
What To Do
Avoid this combination if you have moderate to severe kidney or liver disease.
FDA Label Information
Fesoterodine Patients with moderate to severe renal or hepatic impairment : Contraindicated during and 2 weeks after itraconazole treatment.
Itraconazole Also Interacts With
- Isavuconazonium major
- Lurasidone major
- Pimozide major
- Methadone major
- Midazolam major
Fesoterodine Also Interacts With
- Darunavir major
- Ketoconazole moderate
- Clarithromycin moderate
- Estradiol minor
- Diltiazem minor
Frequently Asked Questions
Can I take Itraconazole and Fesoterodine together?
This is a major interaction. Avoid this combination if you have moderate to severe kidney or liver disease.
How serious is the interaction between Itraconazole and Fesoterodine?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Itraconazole and Fesoterodine interact?
Itraconazole prevents the body from getting rid of fesoterodine, leading to higher amounts of the drug in your blood.
Understanding the Itraconazole and Fesoterodine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Itraconazole belongs to the Azole Antifungal class and Fesoterodine belongs to the Anticholinergic (Overactive Bladder) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Itraconazole prevents the body from getting rid of fesoterodine, leading to higher amounts of the drug in your blood. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Itraconazole has 116 total documented interactions on file in this dataset, and Fesoterodine has 15. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Avoid this combination if you have moderate to severe kidney or liver disease. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Itraconazole or Fesoterodine based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.