Drug & supplement interaction

Catechu + Metolazone

Metolazone brand names: Diulo, Zaroxolyn, Mykrox.

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

Catechu has a moderate interaction with Metolazone. Theoretically, concomitant use with antihypertensive drugs might increase the risk of hypotension.

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

Catechu and Metolazone

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Metolazone

Metolazone falls under ANTIHYPERTENSIVE DRUGS — the group Catechu interacts with.

Theoretically, concomitant use with antihypertensive drugs might increase the risk of hypotension.
Catechu might lower blood pressure.
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 simple version: metolazone is a water pill that lowers blood pressure by helping your body get rid of extra salt and fluid. Catechu, on its own, may nudge your blood pressure down a little too. Put the two together and the concern is that your pressure could dip more than expected.

If that happens, you might feel dizzy or lightheaded, especially when standing up quickly, and you could feel tired or a bit faint. I want to be honest about the strength of this, though: it's theoretical, based on lab and animal data, not real patient studies, so for most folks it's a minor caution rather than a red flag. Still, if you're already prone to low pressure or dizziness, check with your pharmacist or doctor before adding catechu.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sham JS, Chiu KW, Pang PK. Hypotensive action of Acacia catechu. Planta Med 1984;50:177-80.

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

Catechu Also Interacts With Other Medications

Catechu has 474 moderate known drug interactions in our database — the Metolazone one above is one of them. If you take anything else, check it against the full list below.

Moderate 474 No known interaction 2,356 (incl. Metolazone)
Taking anything else?

Check Another of Your Medications Against Catechu

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

Everything else you take

See Every Supplement That Interacts With Metolazone

This page covers Catechu only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metolazone page lists 222 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), Dolomite (major) and Lithium (major).

By severity: 8 major · 190 moderate · 24 minor.

Open the Metolazone interaction page

One more smart check

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

We hold 122 real supplement products containing Catechu, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Catechu. Your product may carry other ingredients that interact with Metolazone too, on top of Catechu — 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 Catechu and Metolazone 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 Catechu
Top half

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

29 days ago today
Medication Metolazone
Steady interest

#1,815 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 Catechu

What is Catechu?

Catechu
  • Mouth and throat soreness
  • Diarrhea and digestive upset
  • Skin wounds and bleeding gums
  • Astringent gargles and rinses
  • Traditional remedy for inflammation

Catechu is an astringent extract made from the heartwood of the Acacia (Senegalia) catechu tree, used traditionally for mouth sores, sore throat, diarrhea, and minor skin problems. Strong human evidence is lacking for most uses, so it should be viewed as a traditional remedy rather than a proven treatment. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Read the full Catechu monograph & all interactions
Medication

About Metolazone

What Is Metolazone Used For?

Brand names: Diulo, Zaroxolyn, Mykrox

Metolazone tablets are used to treat edema (excess fluid buildup) linked to congestive heart failure or kidney diseases — including nephrotic syndrome and conditions with reduced kidney function. They are also used to treat high blood pressure (hypertension), either alone or alongside other blood pressure medications.

Metolazone tablets may also be used during pregnancy when edema is caused by a medical condition rather than normal pregnancy changes — but routine use in otherwise healthy pregnant women is not appropriate.

See full Metolazone drug information
Keep checking

Other Drugs & Catechu

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

0Major
474Moderate
0Minor
2,355No known interaction
474 Moderate 2,355 No interaction
Moderate

474 interactions

Showing 60 of 474 moderate interactions — see all 474 on the Catechu page.

No interaction 2,355 drugs checked — show the list

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

Showing the 60 most looked-up of 2,355 medications checked with no known interaction — see the full Catechu list.

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

Can you take Catechu with Metolazone?
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 Catechu and Metolazone 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 Metolazone and Catechu?

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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.