What the FDA labels say about taking them together
Erythromycin and fesoterodine
Fesoterodine's FDA label of April 7, 2026 names erythromycin in its drug interactions section; the erythromycin labels PlainMeds reads (4) do not name fesoterodine. The fesoterodine label: “No dosing adjustments are recommended in the presence of moderate CYP3A4 inhibitors.”
Check it at the source: the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the fesoterodine FDA label on DailyMed (effective April 7, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the erythromycin label say about fesoterodine?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do 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 (Erythromycin), Teva Pharmaceuticals USA, Inc., effective August 1, 2024 (SPL set 75a0bd5a-d09f-483b-bfd8-f8343b149eb2), via openFDA; the full label on DailyMed
What does the fesoterodine label say about erythromycin?
Fesoterodine label, drug interactionsNo dosing adjustments are recommended in the presence of moderate CYP3A4 inhibitors (e.g., erythromycin, fluconazole, diltiazem, verapamil and grapefruit juice).
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
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
| Erythromycin | Fesoterodine | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | Overactive bladder |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 mg tablet | $0.794 per tablet 4 mg tablet |
| 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