Thioridazine and Propranolol Interaction
Drug interaction information between Thioridazine and Propranolol.
Thioridazine and Propranolol have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Thioridazine and Propranolol. 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
Propranolol slows down how fast your body can break down thioridazine. This causes the level of thioridazine in your blood to rise to a much higher level than normal.
FDA Label Information
Drug Interactions Reduced cytochrome P450 2D6 isozyme activity, drugs which inhibit this isozyme (e.g., fluoxetine and paroxetine), and certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine. Propranolol Concurrent administration of propranolol (100 mg to 800 mg daily) has been reported to produce increases in plasma levels of thioridazine (approximately 50% to 400%) and its metabolites (approximately 80% to 300%). Propranolol and thioridazine should not be coadministered.
Thioridazine Also Interacts With
- Fluoxetine major
- Paroxetine major
- Rolapitant major
- Abiraterone moderate
- Darifenacin moderate
Frequently Asked Questions
What SPL severity band is on file for Thioridazine + Propranolol?
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?
Propranolol has 44 labeled pairs on file vs Thioridazine's 17. In the minor band specifically: Thioridazine has 11 (also Pindolol, Bupropion, Carbamazepine, Clozapine); Propranolol has 44 (also Clonidine, Diltiazem, Warfarin, Verapamil).
What mechanism field is on file for Thioridazine and Propranolol?
Propranolol slows down how fast your body can break down thioridazine. This causes the level of thioridazine in your blood to rise to a much higher level than normal.
Thioridazine carries more major-labeled pairs than Propranolol
SPL source-record counts only. This page's band is minor · classes on file: Thioridazine (Typical Antipsychotic (Phenothiazine)); Propranolol (Non-Selective Beta-Blocker).
Thioridazine has 3 major-labeled pairs vs Propranolol's 0. This page itself is in the minor band, not the major band.
3 major · 3 moderate · 11 minor · 17 total
- Other minor peers for Thioridazine
- Pindolol
- Bupropion
- Carbamazepine
- Clozapine
0 major · 0 moderate · 44 minor · 44 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.