Drug & supplement interaction

Green Tea + Chlorpromazine

Chlorpromazine brand names: Thorazine, Thorazine Spansules.

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

Green Tea has a minor interaction with Chlorpromazine. Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.

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

Green Tea and Chlorpromazine

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

Minor

PHENOTHIAZINES

Why this applies to Chlorpromazine

Chlorpromazine falls under PHENOTHIAZINES — the group Green Tea interacts with.

Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.
Green tea contains caffeine. Phenothiazines can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2).
Severity Minor 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 a small thing worth knowing if you drink green tea while taking chlorpromazine (Thorazine). Green tea naturally contains caffeine, and chlorpromazine can slow down the liver enzyme (called CYP1A2) that normally clears caffeine out of your body. In theory, that means caffeine could hang around a bit longer, so you might feel jittery, have trouble sleeping, notice a racing heartbeat, or feel restless. It's the caffeine that builds up here, not the chlorpromazine itself.

The good news: this is rated minor and is based only on lab-type evidence, not real patient reports. Normal cups of green tea are unlikely to cause trouble for most people. If you take concentrated green tea extracts or feel wired, mention it to your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wojcikowski, J. and Daniel, W. A. Perazine at therapeutic drug concentrations inhibits human cytochrome P450 isoenzyme 1A2 (CYP1A2) and caffeine metabolism--an in vitro study. Pharmacol Rep. 2009;61(5):851-858. PubMed
  2. Daniel, W. A., Syrek, M., Rylko, Z., and Kot, M. Effects of phenothiazine neuroleptics on the rate of caffeine demethylation and hydroxylation in the rat liver. Pol.J Pharmacol 2001;53(6):615-621.

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

Green Tea Also Interacts With Other Medications

Green Tea has 13 major, 905 moderate, 374 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.

Major 13 Moderate 905 Minor 374 No known interaction 1,538 (incl. Chlorpromazine)
Taking anything else?

Check Another of Your Medications Against Green Tea

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

From our Q&A

Questions About Green Tea 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 Green Tea 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 Green Tea 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 Green Tea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 9,084 real supplement products containing Green Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Green Tea. Your product may carry other ingredients that interact with Chlorpromazine too, on top of Green Tea — 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 Green Tea 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 Green Tea
Top 5%

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

29 days ago today
Medication Chlorpromazine
Steady interest

#1,773 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 Green Tea

What is Green Tea?

Green Tea
  • Antioxidant support
  • Weight loss
  • Heart health
  • Mental alertness
  • Cancer risk reduction

Green tea is a popular beverage rich in antioxidants called catechins, and drinking it in normal amounts is considered safe for most people. Concentrated green tea extracts are a different story—they may help modestly with weight or heart health for some, but high doses have been linked to rare liver problems. Talk to your pharmacist or doctor before taking green tea supplements, especially if you have liver concerns or are pregnant.

Read the full Green Tea 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 & Green Tea

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

13Major
905Moderate
374Minor
1,537No known interaction
13 Major 905 Moderate 374 Minor 1,537 No interaction
Major

13 interactions

Moderate

905 interactions

Showing 60 of 905 moderate interactions — see all 905 on the Green Tea page.

Minor

374 interactions

Showing 60 of 374 minor interactions — see all 374 on the Green Tea page.

No interaction 1,537 drugs checked — show the list

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

Showing the 60 most looked-up of 1,537 medications checked with no known interaction — see the full Green Tea list.

See the full Green Tea 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
Green Tea 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 Green Tea and Chlorpromazine Together: Common Questions

Can you take Green Tea with Chlorpromazine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Green Tea and Chlorpromazine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Chlorpromazine and Green Tea?

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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.