Fesoterodine and Diltiazem Interaction
Drug interaction information between Fesoterodine and Diltiazem.
Fesoterodine and Diltiazem have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Fesoterodine and Diltiazem. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Diltiazem blocks the enzyme that breaks down fesoterodine, which can slightly increase the amount of medicine in your body.
FDA Label Information
No dosing adjustments are recommended in the presence of moderate CYP3A4 inhibitors (e.g., erythromycin, fluconazole, diltiazem, verapamil and grapefruit juice).
Fesoterodine Also Interacts With
- Darunavir major
- Itraconazole major
- Ketoconazole moderate
- Clarithromycin moderate
- Estradiol minor
Diltiazem Also Interacts With
- Ezetimibe major
- Ezetimibe/Simvastatin major
- Simvastatin major
- Theophylline major
- Rifampin moderate
Frequently Asked Questions
What SPL severity band is on file for Fesoterodine + Diltiazem?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Diltiazem has 46 labeled pairs on file vs Fesoterodine's 15. In the minor band specifically: Fesoterodine has 11 (also Estradiol, Warfarin, Fluconazole, Verapamil); Diltiazem has 35 (also Buspirone, Pravastatin, Lovastatin, Cyclosporine).
What mechanism field is on file for Fesoterodine and Diltiazem?
Diltiazem blocks the enzyme that breaks down fesoterodine, which can slightly increase the amount of medicine in your body.
Diltiazem carries more major-labeled pairs than Fesoterodine
SPL source-record counts only. This page's band is minor · classes on file: Fesoterodine (Anticholinergic (Overactive Bladder)); Diltiazem (Calcium Channel Blocker).
Diltiazem has 4 major-labeled pairs vs Fesoterodine's 2. This page itself is in the minor band, not the major band.
2 major · 2 moderate · 11 minor · 15 total
- Other minor peers for Fesoterodine
- Estradiol
- Warfarin
- Fluconazole
- Verapamil
4 major · 7 moderate · 35 minor · 46 total
- Other minor peers for Diltiazem
- Buspirone
- Pravastatin
- Lovastatin
- Cyclosporine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.