Thioridazine and Paroxetine Interaction
Drug interaction information between Thioridazine and Paroxetine.
Thioridazine and Paroxetine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Thioridazine and Paroxetine. 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
Paroxetine increases the amount of thioridazine in your blood by slowing down its breakdown. This can lead to a dangerous heart condition where the heart's electrical timing is thrown off.
FDA Label Information
Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Pimozide and Thioridazine Clinical Impact Increased plasma concentrations of pimozide and thioridazine, drugs with a narrow therapeutic index, may increase the risk of QTc prolongation and ventricular arrhythmias. Intervention Paroxetine is contraindicated in patients taking pimozide or thioridazine [see Contraindications ( 4 )] .
Thioridazine Also Interacts With
- Fluoxetine major
- Rolapitant major
- Abiraterone moderate
- Darifenacin moderate
- Tetrabenazine moderate
Paroxetine Also Interacts With
- Linezolid major
- Pimozide major
- Phenelzine moderate
- Tranylcypromine moderate
- Selegiline moderate
Frequently Asked Questions
What SPL severity band is on file for Thioridazine + Paroxetine?
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?
Paroxetine has 51 labeled pairs on file vs Thioridazine's 17. In the major band specifically: Thioridazine has 3 (also Fluoxetine, Rolapitant); Paroxetine has 3 (also Linezolid, Pimozide).
What mechanism field is on file for Thioridazine and Paroxetine?
Paroxetine increases the amount of thioridazine in your blood by slowing down its breakdown. This can lead to a dangerous heart condition where the heart's electrical timing is thrown off.
Paroxetine's labeled portfolio outnumbers Thioridazine
SPL source-record counts only. This page's band is major · classes on file: Thioridazine (Typical Antipsychotic (Phenothiazine)); Paroxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
3 major · 3 moderate · 11 minor · 17 total
- Other major peers for Thioridazine
- Fluoxetine
- Rolapitant
3 major · 4 moderate · 44 minor · 51 total
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.