Thioridazine and Fluoxetine Interaction
Drug interaction information between Thioridazine and Fluoxetine.
Thioridazine and Fluoxetine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Thioridazine 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
These drugs can cause serious heart rhythm problems when used at the same time. Because fluoxetine stays in your system for a long time, the danger remains even after you stop taking it.
FDA Label Information
NSAIDs, Aspirin, Warfarin): May potentiate the risk of bleeding ( 7.4 ) Drugs Tightly Bound to Plasma Proteins: May cause a shift in plasma concentrations ( 7.6 , 7.7 ) Olanzapine: When used in combination with fluoxetine, also refer to the Drug Interactions section of the package insert for Symbyax ( 7.7 ) Drugs that Prolong the QT Interval: Do not use fluoxetine with thioridazine or pimozide. Thioridazine — Thioridazine should not be administered with fluoxetine or within a minimum of 5 weeks after fluoxetine has been discontinued, because of the risk of QT Prolongation [see...
Thioridazine Also Interacts With
- Paroxetine major
- Rolapitant major
- Abiraterone moderate
- Darifenacin moderate
- Tetrabenazine moderate
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Clonazepam major
Frequently Asked Questions
What SPL severity band is on file for Thioridazine + Fluoxetine?
Compiled FDA labeling labels this pair major. 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 Thioridazine's 17. In the major band specifically: Thioridazine has 3 (also Paroxetine, Rolapitant); Fluoxetine has 6 (also Aspirin, Warfarin, Olanzapine, Pimozide).
What mechanism field is on file for Thioridazine and Fluoxetine?
These drugs can cause serious heart rhythm problems when used at the same time. Because fluoxetine stays in your system for a long time, the danger remains even after you stop taking it.
Fluoxetine carries more major-labeled pairs than Thioridazine
SPL source-record counts only. This page's band is major · classes on file: Thioridazine (Typical Antipsychotic (Phenothiazine)); Fluoxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
Fluoxetine has 6 major-labeled pairs vs Thioridazine's 3.
3 major · 3 moderate · 11 minor · 17 total
- Other major peers for Thioridazine
- Paroxetine
- Rolapitant
6 major · 19 moderate · 43 minor · 68 total
- Other major peers for Fluoxetine
- Aspirin
- Warfarin
- Olanzapine
- Pimozide
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.