Drug & supplement interaction

Oolong Tea + Bendroflumethiazide, Rauwolfia Serpentina

Bendroflumethiazide, Rauwolfia Serpentina brand name: Rauzide.

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

Oolong Tea has a moderate interaction with Bendroflumethiazide, Rauwolfia Serpentina. Theoretically, using oolong tea with diuretic drugs might increase the risk of hypokalemia.

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

Oolong Tea and Bendroflumethiazide, Rauwolfia Serpentina

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

Moderate

DIURETIC DRUGS

Why this applies to Bendroflumethiazide, Rauwolfia Serpentina

Bendroflumethiazide, Rauwolfia Serpentina falls under DIURETIC DRUGS — the group Oolong Tea interacts with.

Theoretically, using oolong tea with diuretic drugs might increase the risk of hypokalemia.
Oolong tea contains caffeine. In excessive amounts, caffeine 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

Rauzide combines two ingredients: bendroflumethiazide, a thiazide "water pill," and rauwolfia, an older blood pressure medicine. The thiazide part is the piece that matters here. Like most diuretics, it can push your potassium levels down over time. The concern on file is that the caffeine in oolong tea, when you drink a lot of it, can also nudge potassium lower by shifting it inside your cells. Stacked together, the worry is a slightly bigger dip in potassium.

To be honest, this is a theoretical caution based on how these things work, not strong proof, and a cup or two of tea is unlikely to cause trouble. Still, low potassium can bring on muscle cramps, weakness, or an irregular heartbeat. If you drink large amounts daily, mention it to your pharmacist or doctor, who can check your potassium.

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

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

Oolong Tea Also Interacts With Other Medications

Oolong Tea has 8 major, 517 moderate, 126 minor known drug interactions in our database — the Bendroflumethiazide, Rauwolfia Serpentina one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 517 Minor 126 No known interaction 2,179 (incl. Bendroflumethiazide, Rauwolfia Serpentina)
Taking anything else?

Check Another of Your Medications Against Oolong Tea

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

Everything else you take

See Every Supplement That Interacts With Bendroflumethiazide, Rauwolfia Serpentina

This page covers Oolong Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Bendroflumethiazide, Rauwolfia Serpentina page lists 227 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 Dolomite (major).

By severity: 10 major · 192 moderate · 25 minor.

From our pharmacist’s overview on the Bendroflumethiazide, Rauwolfia Serpentina page

“Rauzide combines two blood-pressure medicines, the thiazide diuretic bendroflumethiazide and rauwolfia serpentina, so anything that also lowers pressure, pulls off fluid, or shifts electrolytes lands on already sensitive ground. This page warrants real caution.”

Reviewed by 2 · Jul 18, 2026

Open the Bendroflumethiazide, Rauwolfia Serpentina interaction page

One more smart check

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

We hold 75 real supplement products containing Oolong Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oolong Tea. Your product may carry other ingredients that interact with Bendroflumethiazide, Rauwolfia Serpentina too, on top of Oolong 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 Oolong Tea and Bendroflumethiazide, Rauwolfia Serpentina 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 Oolong Tea
Steady interest

#1,108 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Bendroflumethiazide, Rauwolfia Serpentina
Steady interest

#1,819 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 Oolong Tea

What is Oolong Tea?

  • Weight management
  • Mental alertness and energy
  • Heart health
  • Blood sugar support
  • Antioxidant support

Oolong tea is a traditional partially oxidized tea made from the same plant as green and black tea, and it provides caffeine and plant antioxidants. As a beverage it is generally considered safe for most healthy adults in moderate amounts, but evidence for specific health benefits like weight loss or blood sugar control is limited. If you have heart, blood pressure, or caffeine-sensitivity concerns, talk with your pharmacist or doctor.

Read the full Oolong Tea monograph & all interactions
Keep checking

Other Drugs & Oolong Tea

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

8Major
517Moderate
126Minor
2,178No known interaction
8 Major 517 Moderate 126 Minor 2,178 No interaction
Major

8 interactions

Moderate

517 interactions

Showing 60 of 517 moderate interactions — see all 517 on the Oolong Tea page.

Minor

126 interactions

Showing 60 of 126 minor interactions — see all 126 on the Oolong Tea page.

No interaction 2,178 drugs checked — show the list

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

Showing the 60 most looked-up of 2,178 medications checked with no known interaction — see the full Oolong Tea list.

See the full Oolong Tea interactions page
See every supplement checked against Bendroflumethiazide, Rauwolfia Serpentina, 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
Oolong Tea monograph › Uses, safety, and every drug interaction in one place Bendroflumethiazide, Rauwolfia Serpentina supplement interactions › Every supplement checked against Bendroflumethiazide, Rauwolfia Serpentina, 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 Oolong Tea and Bendroflumethiazide, Rauwolfia Serpentina Together: Common Questions

Can you take Oolong Tea with Bendroflumethiazide, Rauwolfia Serpentina?
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 Oolong Tea and Bendroflumethiazide, Rauwolfia Serpentina 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 Bendroflumethiazide, Rauwolfia Serpentina and Oolong 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.