Tolterodine and Fluoxetine Interaction
Drug interaction information between Tolterodine and Fluoxetine.
Tolterodine and Fluoxetine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Tolterodine and Fluoxetine. 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
Fluoxetine slows down the process your body uses to get rid of tolterodine, leading to higher levels of the drug in your blood.
FDA Label Information
( 7.6 ) 7.1 Potent CYP2D6 Inhibitors Fluoxetine, a potent inhibitor of CYP2D6 activity, significantly inhibited the metabolism of tolterodine immediate release in CYP2D6 extensive metabolizers, resulting in a 4.8-fold increase in tolterodine AUC. No dose adjustment is required when tolterodine and fluoxetine are co-administered [see Clinical Pharmacology (12.3) ] . Drug Interactions Potent CYP2D6 Inhibitors Fluoxetine is a selective serotonin reuptake inhibitor and a potent inhibitor of CYP2D6 activity.
Tolterodine Also Interacts With
- Clarithromycin moderate
- Omeprazole minor
- Hydrochlorothiazide minor
- Furosemide minor
- Estradiol minor
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Thioridazine major
Frequently Asked Questions
What SPL severity band is on file for Tolterodine + Fluoxetine?
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?
Fluoxetine has 68 labeled pairs on file vs Tolterodine's 15. In the minor band specifically: Tolterodine has 14 (also Omeprazole, Hydrochlorothiazide, Furosemide, Estradiol); Fluoxetine has 43 (also Ketoconazole, Lithium, Moxifloxacin, Erythromycin).
What mechanism field is on file for Tolterodine and Fluoxetine?
Fluoxetine slows down the process your body uses to get rid of tolterodine, leading to higher levels of the drug in your blood.
Fluoxetine carries more major-labeled pairs than Tolterodine
SPL source-record counts only. This page's band is minor · classes on file: Tolterodine (Anticholinergic (Overactive Bladder)); Fluoxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
Fluoxetine has 6 major-labeled pairs vs Tolterodine's 0. This page itself is in the minor band, not the major band.
0 major · 1 moderate · 14 minor · 15 total
- Other minor peers for Tolterodine
- Omeprazole
- Hydrochlorothiazide
- Furosemide
- Estradiol
6 major · 19 moderate · 43 minor · 68 total
- Other minor peers for Fluoxetine
- Ketoconazole
- Lithium
- Moxifloxacin
- Erythromycin
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.