Drug & supplement interaction

Green Coffee + Meperidine, Promethazine

Meperidine, Promethazine brand names: Meprozine, Mepergan.

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

Green Coffee has a minor interaction with Meperidine, Promethazine. 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?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Green Coffee and Meperidine, Promethazine

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

Minor

PHENOTHIAZINES

Why this applies to Meperidine, Promethazine

Meperidine, Promethazine falls under PHENOTHIAZINES — the group Green Coffee interacts with.

Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.
Green coffee can contain 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 the gist: Meprozine and Mepergan contain promethazine, which is part of the phenothiazine family. Promethazine can mildly slow down a liver enzyme (called CYP1A2) that helps clear caffeine out of your body. Since green coffee naturally carries caffeine, the caffeine could hang around a bit longer than usual. That might mean more jitteriness, a racing heart, trouble sleeping, or feeling restless.

The good news is this is rated as a minor interaction, and the evidence behind it comes only from lab and animal studies, not real patients. So for most people it isn't a big worry, especially with everyday coffee amounts. Just keep in mind that concentrated green coffee supplements pack more caffeine than a cup of coffee. If you notice extra restlessness or a pounding heart, or you take this combo regularly, it's worth a quick chat with 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 Coffee Also Interacts With Other Medications

Green Coffee has 8 major, 442 moderate, 221 minor known drug interactions in our database — the Meperidine, Promethazine one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 442 Minor 221 No known interaction 2,159 (incl. Meperidine, Promethazine)
Taking anything else?

Check Another of Your Medications Against Green Coffee

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

Everything else you take

See Every Supplement That Interacts With Meperidine, Promethazine

This page covers Green Coffee only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Meperidine, Promethazine page lists 207 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), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Henbane (major).

By severity: 10 major · 160 moderate · 37 minor.

From our pharmacist’s overview on the Meperidine, Promethazine page

“Meprozine combines meperidine, an opioid painkiller, with promethazine, a sedating antihistamine, so it already slows the brain on two fronts. I would read this list of 207 supplements and herbal ingredients with genuine care, starting with the 10 rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Meperidine, Promethazine interaction page

One more smart check

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

We hold 1,716 real supplement products containing Green Coffee, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Green Coffee. Your product may carry other ingredients that interact with Meperidine, Promethazine too, on top of Green Coffee — 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 Coffee and Meperidine, Promethazine 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 Coffee
Top half

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

29 days ago today
Medication Meperidine, Promethazine
Top 25%

#365 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 Coffee

What is Green Coffee?

Green Coffee
  • Weight loss
  • High blood pressure
  • Blood sugar control
  • Antioxidant support
  • General energy

Green coffee is the unroasted bean of the coffee plant, prized for its high chlorogenic acid content. Some early studies suggest modest benefits for weight, blood pressure, and blood sugar, but the evidence is limited and far from conclusive. It contains caffeine, so people sensitive to stimulants should use caution and check with a pharmacist or doctor first.

Read the full Green Coffee monograph & all interactions
Keep checking

Other Drugs & Green Coffee

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

8Major
442Moderate
221Minor
2,158No known interaction
8 Major 442 Moderate 221 Minor 2,158 No interaction
Major

8 interactions

Moderate

442 interactions

Showing 60 of 442 moderate interactions — see all 442 on the Green Coffee page.

Minor

221 interactions

Showing 60 of 221 minor interactions — see all 221 on the Green Coffee page.

No interaction 2,158 drugs checked — show the list

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

Showing the 60 most looked-up of 2,158 medications checked with no known interaction — see the full Green Coffee list.

See the full Green Coffee interactions page
See every supplement checked against Meperidine, Promethazine, 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 Coffee monograph › Uses, safety, and every drug interaction in one place Meperidine, Promethazine supplement interactions › Every supplement checked against Meperidine, Promethazine, 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 Green Coffee and Meperidine, Promethazine Together: Common Questions

Can you take Green Coffee with Meperidine, Promethazine?
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 Coffee and Meperidine, Promethazine 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 Meperidine, Promethazine and Green Coffee?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.