Drug & supplement interaction

Green Coffee + Hydrochlorothiazide, Methyldopa

Hydrochlorothiazide, Methyldopa brand names: Aldoril 15, Methazide, Aldoril 25, Aldoril D30.

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

Hydrochlorothiazide, Methyldopa falls into 2 drug categories that Green Coffee can interact with; the most serious is rated moderate. Theoretically, concomitant use might increase the risk of hypokalemia.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Green Coffee and Hydrochlorothiazide, Methyldopa

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Green Coffee interacts with whole categories of medication. Hydrochlorothiazide, Methyldopa falls into 2 of those categories, so it can interact with Green Coffee in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

DIURETIC DRUGS

1 of 2

Why this applies to Hydrochlorothiazide, Methyldopa

Hydrochlorothiazide, Methyldopa falls under DIURETIC DRUGS — the group Green Coffee interacts with.

Theoretically, concomitant use might increase the risk of hypokalemia.
Green coffee can contain caffeine. Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.
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 thing to keep in mind with this combo. Your medication includes hydrochlorothiazide, a water pill that naturally pushes potassium out of your body. Green coffee carries caffeine, and in larger amounts caffeine can also nudge potassium lower. Stacked together, the worry is that your potassium could dip a bit further than it would on the diuretic alone.

I want to be honest though: this is a theoretical concern based on how these things work, not strong proof. Low potassium can show up as muscle cramps, weakness, or an irregular heartbeat. A regular cup of coffee is unlikely to matter, but concentrated green coffee supplements are a different story. Since your potassium may already get checked on this medication, just mention the supplement to your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Norager, C. B., Jensen, M. B., Weimann, A., and Madsen, M. R. Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study. Clin Endocrinol (Oxf) 2006;65(2):223-228. PubMed
  2. Simmonds, M. J., Minahan, C. L., and Sabapathy, S. Caffeine improves supramaximal cycling but not the rate of anaerobic energy release. Eur.J Appl Physiol 2010;109(2):287-295. PubMed
  3. Rigato, I., Blarasin, L., and Kette, F. Severe hypokalemia in 2 young bicycle riders due to massive caffeine intake. Clin J Sport Med. 2010;20(2):128-130. PubMed
  4. Ernest, D., Chia, M., and Corallo, C. E. Profound hypokalaemia due to Nurofen Plus and Red Bull misuse. Crit Care Resusc. 2010;12(2):109-110. DOI
  5. Clausen, T. Hormonal and pharmacological modification of plasma potassium homeostasis. Fundam.Clin Pharmacol 2010;24(5):595-605. PubMed
Minor

ANTIHYPERTENSIVE DRUGS

2 of 2

Hydrochlorothiazide, Methyldopa also falls under ANTIHYPERTENSIVE DRUGS.

Theoretically, taking green coffee with antihypertensive drugs might increase the risk of hypotension.
Clinical studies have shown that green coffee extract decreases blood pressure. When used with antihypertensive drugs, green coffee might have additive blood pressure-lowering effects. However, this has not been shown in clinical research.
Severity Minor Likelihood Possible Evidence B

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 combo pill pairs hydrochlorothiazide (a water pill) with methyldopa, and both work to bring your blood pressure down. Green coffee may nudge blood pressure a little lower too, thanks to its chlorogenic acid. Stacked together, the worry is simply additive: your numbers could dip more than expected.

If that happens, you might feel lightheaded, dizzy when standing up, tired, or even a bit faint. Honestly, this is a minor, mostly theoretical concern, and the research backing it is weak. A regular cup of coffee is unlikely to matter much; concentrated green coffee supplements are more likely to add up. Talk with your pharmacist or doctor before starting one, and don't change your medication on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kozuma K, Tsuchiya S, Kohori J, et al. Antihypertensive effect of green coffee bean extract on mildly hypertensive subjects. Hypertens Res. 2005 Sep;28(9):711-8. PubMed
  2. Watanabe T, Arai Y, Mitsui Y, et al. The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension. Clin Exp Hypertens 2006;28:439-49. 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

Green Coffee Also Interacts With Other Medications

Green Coffee has 8 major, 441 moderate, 222 minor known drug interactions in our database — the Hydrochlorothiazide, Methyldopa one above is among them. If you take anything else, check it against the full list below.

Major 8 Moderate 441 Minor 222 No known interaction 2,159 (incl. Hydrochlorothiazide, Methyldopa)
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 Hydrochlorothiazide, Methyldopa

This page covers Green Coffee only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydrochlorothiazide, Methyldopa page lists 261 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Beer (major).

By severity: 13 major · 223 moderate · 25 minor.

From our pharmacist’s overview on the Hydrochlorothiazide, Methyldopa page

“If you take hydrochlorothiazide with methyldopa (Aldoril, Methazide), this list deserves real attention, and the 13 major-rated entries are where to start. Most of the 261 ingredients either push blood pressure lower than intended or add to the diuretic effect, which can drain potassium.”

Reviewed by 2 · Jul 18, 2026

Open the Hydrochlorothiazide, Methyldopa 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 Hydrochlorothiazide, Methyldopa 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 Hydrochlorothiazide, Methyldopa 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

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

29 days ago today
Medication Hydrochlorothiazide, Methyldopa
Top 25%

#290 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
441Moderate
222Minor
2,158No known interaction
8 Major 441 Moderate 222 Minor 2,158 No interaction
Major

8 interactions

Moderate

441 interactions

Showing 60 of 441 moderate interactions — see all 441 on the Green Coffee page.

Minor

222 interactions

Showing 60 of 222 minor interactions — see all 222 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 Hydrochlorothiazide, Methyldopa, 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 Hydrochlorothiazide, Methyldopa supplement interactions › Every supplement checked against Hydrochlorothiazide, Methyldopa, 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 Hydrochlorothiazide, Methyldopa Together: Common Questions

Can you take Green Coffee with Hydrochlorothiazide, Methyldopa?
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.
Why are there 2 interactions listed for Green Coffee and Hydrochlorothiazide, Methyldopa?
Hydrochlorothiazide, Methyldopa belongs to more than one drug category, and Green Coffee interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Green Coffee and Hydrochlorothiazide, Methyldopa 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

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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.