Drug & supplement interaction

Grape + Chlorpromazine

Chlorpromazine brand names: Thorazine, Thorazine Spansules.

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

Grape has a moderate interaction with Chlorpromazine. Theoretically, grape seed extract may increase the levels of CYP2D6 substrates.

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

Grape and Chlorpromazine

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Chlorpromazine

Chlorpromazine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Grape interacts with.

Theoretically, grape seed extract may increase the levels of CYP2D6 substrates.
In vitro evidence suggests that grape seed extract might inhibit CYP2D6 enzymes. However, this interaction 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 gist for Chlorpromazine (Thorazine). Your body relies partly on a liver enzyme called CYP2D6 to break this medicine down. Lab studies suggest concentrated grape seed extract might slow that enzyme. If it does, chlorpromazine could clear a little more slowly and build up, which in theory could nudge its effects and side effects upward, things like drowsiness, dizziness, dry mouth, low blood pressure when you stand, or constipation.

That said, this is only seen in test-tube research and hasn't been shown in real people, so I wouldn't lose sleep over it. Eating grapes or drinking grape juice is very unlikely to matter. If you're thinking about a grape seed extract supplement, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Nishikawa, M., Ariyoshi, N., Kotani, A., Ishii, I., Nakamura, H., Nakasa, H., Ida, M., Nakamura, H., Kimura, N., Kimura, M., Hasegawa, A., Kusu, F., Ohmori, S., Nakazawa, K., and Kitada, M. Effects of continuous ingestion of green tea or grape seed extra

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

Grape Also Interacts With Other Medications

Grape has 867 moderate, 42 minor known drug interactions in our database — the Chlorpromazine one above is one of them. If you take anything else, check it against the full list below.

Moderate 867 Minor 42 No known interaction 1,921 (incl. Chlorpromazine)
Taking anything else?

Check Another of Your Medications Against Grape

Covers the 2,830 medications we’ve checked against Grape. Pick one to open its full report.

From our Q&A

Questions About Grape or Chlorpromazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Grape or Chlorpromazine, 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 Chlorpromazine

This page covers Grape only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpromazine page lists 211 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), American Hellebore (major), Arsenic (major) and Beer (major).

By severity: 17 major · 159 moderate · 35 minor.

Open the Chlorpromazine interaction page

One more smart check

Taking Grape as Part of a Dietary Supplement Product? Check It for Interactions

We hold 8,053 real supplement products containing Grape, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Grape. Your product may carry other ingredients that interact with Chlorpromazine too, on top of Grape — 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 Grape and Chlorpromazine 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 Grape
Top 5%

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

29 days ago today
Medication Chlorpromazine
Steady interest

#1,811 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 Grape

What is Grape?

Grape
  • Antioxidant support
  • Heart and circulation health
  • Vein problems (such as varicose veins)
  • Eye health
  • General anti-inflammatory support

Grapes and grape products like grape seed extract contain antioxidant compounds such as resveratrol and proanthocyanidins that may support heart and blood vessel health. While the food is healthy and generally safe, the supplement evidence for treating specific conditions is mostly limited or preliminary. Talk with your pharmacist or doctor before starting a grape supplement.

Read the full Grape monograph & all interactions
Medication

About Chlorpromazine

What Is Chlorpromazine Used For?

Brand names: Thorazine, Thorazine Spansules

Chlorpromazine is used to manage psychotic disorders and treat schizophrenia. It also controls nausea and vomiting, relieves restlessness and apprehension before surgery, and controls the manic phase of manic-depressive illness. Other uses include relief of intractable hiccups, treatment of acute intermittent porphyria, and use as an adjunct in tetanus treatment.

In children ages 1 to 12, it is used for severe behavioral problems marked by explosive or combative behavior, and for short-term treatment of hyperactive children with conduct disorders. The oral forms are also approved for the management of manifestations of psychotic disorders broadly, in addition to the uses shared with the injection form.

See full Chlorpromazine drug information
Keep checking

Other Drugs & Grape

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

0Major
867Moderate
42Minor
1,920No known interaction
867 Moderate 42 Minor 1,920 No interaction
Moderate

867 interactions

Showing 60 of 867 moderate interactions — see all 867 on the Grape page.

Minor

42 interactions

No interaction 1,920 drugs checked — show the list

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

Showing the 60 most looked-up of 1,920 medications checked with no known interaction — see the full Grape list.

See the full Grape interactions page
See every supplement checked against Chlorpromazine, 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
Grape monograph › Uses, safety, and every drug interaction in one place Chlorpromazine supplement interactions › Every supplement checked against Chlorpromazine, ranked by severity Chlorpromazine 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 Grape and Chlorpromazine Together: Common Questions

Can you take Grape with Chlorpromazine?
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 Grape and Chlorpromazine 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 Chlorpromazine and Grape?

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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.