Drug & supplement interaction

Black Tea + Isopropamide, Trifluoperazine

Isopropamide, Trifluoperazine brand names: Stelabid No 1, Stelabid No 2, Stelabid Forte.

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

Black Tea has a minor interaction with Isopropamide, Trifluoperazine. 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

Black Tea and Isopropamide, Trifluoperazine

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

Minor

PHENOTHIAZINES

Why this applies to Isopropamide, Trifluoperazine

Isopropamide, Trifluoperazine falls under PHENOTHIAZINES — the group Black Tea interacts with.

Theoretically, phenothiazines might increase the levels and adverse effects of caffeine. Also, black tea may bind to phenothiazines and reduce their absorption.
Black tea contains caffeine. Phenothiazines can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2). Additionally, the tannins in black tea may bind to phenothiazines in the gastrointestinal tract and reduce their absorption.
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

Your Stelabid contains trifluoperazine, a phenothiazine, paired with isopropamide. Here there are really two small, mostly theoretical things going on with black tea. First, trifluoperazine can slow down the enzyme (CYP1A2) that clears caffeine from your body, so the caffeine in your tea may linger a bit longer. That could mean more jitteriness, a faster heartbeat, or trouble sleeping. Second, the tannins in tea can grab onto the medicine in your gut and slightly reduce how much you absorb, which could mean a touch less benefit.

Honestly, this is based on lab-type evidence and is rated minor, so a cup or two with food usually isn't a big deal. To play it safe, separate your tea from your dose by an hour or two, and check with your pharmacist if you notice changes.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lasswell WL Jr, Weber SS, Wilkins JM. In vitro interaction of neuroleptics and tricylic antidepressants with coffee, tea, and gallotannic acid. J Pharm Sci 1984;73:1056-8. PubMed
  2. Kulhanek F, Linde OK, Meisenberg G. Precipitation of antipsychotic drugs in interaction with coffee or tea. Lancet 1979;2:1130.
  3. 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
  4. 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

Black Tea Also Interacts With Other Medications

Black Tea has 8 major, 572 moderate, 113 minor known drug interactions in our database — the Isopropamide, Trifluoperazine one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 572 Minor 113 No known interaction 2,137 (incl. Isopropamide, Trifluoperazine)
Taking anything else?

Check Another of Your Medications Against Black Tea

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

Everything else you take

See Every Supplement That Interacts With Isopropamide, Trifluoperazine

This page covers Black Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Isopropamide, Trifluoperazine page lists 76 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Indian Snakeroot (major), Rauvolfia Vomitoria (major) and Scopolia (major).

By severity: 5 major · 48 moderate · 23 minor.

From our pharmacist’s overview on the Isopropamide, Trifluoperazine page

“Henbane sits at the top of this list for good reason. Stelabid pairs isopropamide, an anticholinergic that calms gut spasm, with trifluoperazine, a phenothiazine antipsychotic, and henbane's atropine-like alkaloids can pile onto both drugs at once, risking severe dry mouth, confusion, and a racing heart.”

Reviewed by 2 · Jul 18, 2026

Open the Isopropamide, Trifluoperazine interaction page

One more smart check

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

We hold 271 real supplement products containing Black Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Tea. Your product may carry other ingredients that interact with Isopropamide, Trifluoperazine too, on top of Black 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 Black Tea and Isopropamide, Trifluoperazine 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 Black Tea
Top 25%

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

29 days ago today
Medication Isopropamide, Trifluoperazine
Top 25%

#288 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 Black Tea

What is Black Tea?

  • Mental alertness and energy
  • Heart health support
  • Blood pressure and cholesterol
  • Digestive complaints
  • Weight management
  • Antioxidant support

Black tea is a popular caffeinated drink made from the fully oxidized leaves of the Camellia sinensis plant, and it contains caffeine and antioxidant plant compounds. Moderate tea drinking is generally safe for most adults and may modestly support heart health and alertness, but it is not a proven treatment for any disease. If you are pregnant, breastfeeding, sensitive to caffeine, or taking medicines, talk to your pharmacist or doctor.

Read the full Black Tea monograph & all interactions
Keep checking

Other Drugs & Black Tea

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

8Major
572Moderate
113Minor
2,136No known interaction
8 Major 572 Moderate 113 Minor 2,136 No interaction
Major

8 interactions

Moderate

572 interactions

Showing 60 of 572 moderate interactions — see all 572 on the Black Tea page.

Minor

113 interactions

Showing 60 of 113 minor interactions — see all 113 on the Black Tea page.

No interaction 2,136 drugs checked — show the list

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

Showing the 60 most looked-up of 2,136 medications checked with no known interaction — see the full Black Tea list.

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

Can you take Black Tea with Isopropamide, Trifluoperazine?
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 Black Tea and Isopropamide, Trifluoperazine 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 Isopropamide, Trifluoperazine and Black 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.