Naltrexone and Thioridazine Interaction
Drug interaction information between Naltrexone and Thioridazine.
Naltrexone and Thioridazine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Naltrexone and Thioridazine. 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
Taking these two drugs together can cause an additive effect that makes you feel very sleepy and tired. Both medications impact the brain in a way that increases drowsiness.
FDA Label Information
Lethargy and somnolence have been reported following doses of naltrexone hydrochloride and thioridazine.
Naltrexone Also Interacts With
- Disulfiram minor
- Acamprosate minor
- Glecaprevir/Pibrentasvir minor
- Nabilone minor
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 Naltrexone + Thioridazine?
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?
Thioridazine has 17 labeled pairs on file vs Naltrexone's 5. In the minor band specifically: Naltrexone has 5 (also Disulfiram, Acamprosate, Glecaprevir/Pibrentasvir, Nabilone); Thioridazine has 11 (also Propranolol, Pindolol, Bupropion, Carbamazepine).
What mechanism field is on file for Naltrexone and Thioridazine?
Taking these two drugs together can cause an additive effect that makes you feel very sleepy and tired. Both medications impact the brain in a way that increases drowsiness.
Thioridazine carries more major-labeled pairs than Naltrexone
SPL source-record counts only. This page's band is minor · classes on file: Naltrexone (Opioid Antagonist); Thioridazine (Typical Antipsychotic (Phenothiazine)).
Thioridazine has 3 major-labeled pairs vs Naltrexone's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 5 minor · 5 total
- Other minor peers for Naltrexone
- Disulfiram
- Acamprosate
- Glecaprevir/Pibrentasvir
- Nabilone
3 major · 3 moderate · 11 minor · 17 total
- Other minor peers for Thioridazine
- Propranolol
- Pindolol
- Bupropion
- Carbamazepine
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.