What the FDA labels say about taking them together
Fesoterodine and ketoconazole
Fesoterodine's FDA label of April 7, 2026 names ketoconazole in its drug interactions section; the ketoconazole label PlainMeds reads does not name fesoterodine. The fesoterodine label: “Doses of Toviaz greater than 4 mg are not recommended in adult patients taking strong CYP3A4 inhibitors, such as ketoconazole, itraconazole, and clarithromycin.”
Check it at the source: the fesoterodine FDA label on DailyMed (effective April 7, 2026, Pfizer Laboratories Div Pfizer Inc); the ketoconazole FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC).
What does the fesoterodine label say about ketoconazole?
Fesoterodine label, drug interactionsDoses of Toviaz greater than 4 mg are not recommended in adult patients taking strong CYP3A4 inhibitors, such as ketoconazole, itraconazole, and clarithromycin [see Dosage and Administration (2.5) ].
Source: FDA drug label (Toviaz), Pfizer Laboratories Div Pfizer Inc, effective April 7, 2026 (SPL set 5be745f0-8ae7-4c3c-9962-37d6263326f1), via openFDA; the full label on DailyMed
What does the ketoconazole label say about fesoterodine?
Ketoconazole's label (effective January 28, 2026) does not name fesoterodine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (ketoconazole), E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC, effective January 28, 2026 (SPL set cad7c647-34a9-4e4e-83b3-8d78e58f588f), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Fesoterodine | Ketoconazole | |
|---|---|---|
| Labeled for | Overactive bladder | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.794 per tablet 4 mg tablet | $0.249 per gram 2% cream |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once