Drug Interaction Report

Thioridazine and Abiraterone: Interaction Details

A pharmacist-reviewed analysis of the Thioridazine and Abiraterone interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Thioridazine

No brand names on record
+

Abiraterone

Abirtega Yonsa Zytiga Zytiga®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 117 documented Thioridazine interactions, 49 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Increased thioridazine exposure

Interaction Deep Dive

Coadministration of abiraterone acetate (a CYP2D6 inhibitor) with thioridazine (a CYP2D6 substrate with a narrow therapeutic index) may result in increased plasma concentrations of thioridazine and should be avoided. Although not specifically studied with thioridazine, the coadministration of abiraterone acetate and predniSONE with dextromethorphan (another CYP2D6 substrate) resulted in a 2.8-fold and 2.9-fold increase in dextromethorphan Cmax and AUC, respectively. If concomitant use of abiraterone acetate with thioridazine is required, use caution and reduce thioridazine doses as necessary12.

Why it happens (mechanism)

Inhibition of CYP2D6-mediated thioridazine metabolism by abiraterone acetate

Literature reports

1 report — tap to read

a) The Cmax and AUC of dextromethorphan (CYP2D6 substrate) were increased 2.8- and 2.9-fold, respectively when dextromethorphan 30 mg was given with abiraterone acetate 1000 mg daily (plus prednisone). The AUC for dextrorphan, the active metabolite of dextromethorphan, increased approximately 1.3-fold 2.

Common questions

Can I take Thioridazine and Abiraterone together?

Increased thioridazine exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Thioridazine and Abiraterone interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Thioridazine or Abiraterone need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (2)

  1. Product Information: ZYTIGA(R) oral tablets, abiraterone acetate oral tablets. Janssen Biotech Inc (per FDA), Horsham, PA, 2018. DailyMed
  2. Product Information: AKEEGA(TM) oral tablets, niraparib, abiraterone acetate oral tablets. Janssen Biotech, Inc. (per FDA), Horsham, PA, 2023. DailyMed
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Thioridazine

Keep reading about Thioridazine

All Thioridazine interactions (117)
Also serious with: Amisulpride Injection Dasatinib Ofloxacin Oxaliplatin Injection
Abiraterone

Keep reading about Abiraterone

All Abiraterone interactions (164) Abiraterone drug information
Also serious with: Ensitrelvir Abametapir Acarbose Albiglutide
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Thioridazine + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Henbane Indian Snakeroot + 160 more
Abiraterone + Activated Charcoal Beer Grapefruit Siberian Cocklebur St. John's Wort Wine Acacia Rigidula Adrafinil + 173 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.