What the FDA labels say about taking them together
Diltiazem and fesoterodine
Fesoterodine's FDA label of April 7, 2026 names diltiazem in its drug interactions section; the diltiazem 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 diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC); the fesoterodine FDA label on DailyMed (effective April 7, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the diltiazem label say about fesoterodine?
Diltiazem's label (effective August 7, 2026) 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 (TIAZAC EXTENDED RELEASE), Bausch Health US, LLC, effective August 7, 2026 (SPL set c567fe7e-887e-4291-a0d1-2dd3f25cbf25), via openFDA; the full label on DailyMed
What does the fesoterodine label say about diltiazem?
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
| Diltiazem | Fesoterodine | |
|---|---|---|
| Labeled for | High blood pressure, Angina, Atrial fibrillation | Overactive bladder |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.144 per capsule 24h ER(cd) 120 mg capsule | $0.794 per tablet 4 mg tablet |
| Shortage now | A presentation being discontinued | 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