Drug & supplement interaction

Devil's Claw + Thioridazine

Thioridazine brand name: Mellaril.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Devil's Claw has a moderate interaction with Thioridazine. Theoretically, devil's claw might increase levels of drugs metabolized by CYP2C19.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Devil's Claw and Thioridazine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

Why this applies to Thioridazine

Thioridazine falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Devil's Claw interacts with.

Theoretically, devil's claw might increase levels of drugs metabolized by CYP2C19.
In vitro research shows that devil's claw might inhibit CYP2C19, although this has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the idea with Devil's Claw and thioridazine (Mellaril). Your body partly uses an enzyme called CYP2C19 to break thioridazine down. Lab studies (in test tubes, not people) hint that devil's claw may slow that enzyme. If that happened in real life, thioridazine could build up a bit higher than expected, which might mean more side effects like drowsiness, dizziness, low blood pressure, or a fast or irregular heartbeat. Thioridazine already carries a known risk of affecting heart rhythm, so that's the part worth being careful about.

That said, this is only a theoretical concern so far, not something seen in humans. I wouldn't panic, but since thioridazine is a serious medication, please run any devil's claw use past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Devil's Claw Also Interacts With Other Medications

Devil's Claw has 730 moderate, 73 minor known drug interactions in our database — the Thioridazine one above is one of them. If you take anything else, check it against the full list below.

Moderate 730 Minor 73 No known interaction 2,027 (incl. Thioridazine)
Taking anything else?

Check Another of Your Medications Against Devil's Claw

Covers the 2,830 medications we’ve checked against Devil's Claw. Pick one to open its full report.

From our Q&A

Questions About Devil's Claw or Thioridazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Devil's Claw or Thioridazine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Thioridazine

This page covers Devil's Claw only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Thioridazine page lists 168 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 11 major · 125 moderate · 32 minor.

From our pharmacist’s overview on the Thioridazine page

“Thioridazine (Mellaril) is an older antipsychotic already known for disturbing the heart's rhythm, and the supplements that worry me most here do the same thing, stretching the QT interval further. Grapefruit in large amounts sits in that group, alongside ephedra and several other major-rated entries.”

Reviewed by 2 · Jul 18, 2026

Open the Thioridazine interaction page

One more smart check

Taking Devil's Claw as Part of a Dietary Supplement Product? Check It for Interactions

We hold 585 real supplement products containing Devil's Claw, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Devil's Claw. Your product may carry other ingredients that interact with Thioridazine too, on top of Devil's Claw — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Devil's Claw and Thioridazine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Devil's Claw
Top 25%

#289 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Thioridazine
Steady interest

#1,618 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Devil's Claw

What is Devil's Claw?

Devil's Claw
  • Osteoarthritis pain
  • Lower back pain
  • Joint pain and stiffness
  • General inflammation
  • Digestive upset and loss of appetite

Devil's claw is a southern African plant used mainly for arthritis and back pain, and some studies suggest it may help ease these types of discomfort. The evidence is moderate at best, and product strength varies, so talk with your pharmacist or doctor before trying it, especially if you have a health condition or take medications.

Read the full Devil's Claw monograph & all interactions
Medication

About Thioridazine

What Is Thioridazine Used For?

Brand name: Mellaril

Thioridazine Hydrochloride tablets are used for the management of schizophrenia — but only in patients who have already tried at least two other antipsychotic medications without adequate results, either because those drugs didn't work well enough or caused intolerable side effects.

Because thioridazine carries serious heart-rhythm risks, it is considered a last-resort option for schizophrenia, not a first-line treatment. It is not approved for dementia-related psychosis or any other psychiatric condition.

See full Thioridazine drug information
Keep checking

Other Drugs & Devil's Claw

Browse every other medication we’ve checked against Devil's Claw — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
730Moderate
73Minor
2,026No known interaction
730 Moderate 73 Minor 2,026 No interaction
Moderate

730 interactions

Showing 60 of 730 moderate interactions — see all 730 on the Devil's Claw page.

Minor

73 interactions

Showing 60 of 73 minor interactions — see all 73 on the Devil's Claw page.

No interaction 2,026 drugs checked — show the list

We also checked Devil's Claw against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,026 medications checked with no known interaction — see the full Devil's Claw list.

See the full Devil's Claw interactions page
See every supplement checked against Thioridazine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Devil's Claw monograph › Uses, safety, and every drug interaction in one place Thioridazine supplement interactions › Every supplement checked against Thioridazine, ranked by severity Thioridazine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Devil's Claw and Thioridazine Together: Common Questions

Can you take Devil's Claw with Thioridazine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Devil's Claw and Thioridazine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Thioridazine and Devil's Claw?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.