Drug & supplement interaction

Rhubarb + Bendroflumethiazide, Potassium

Bendroflumethiazide, Potassium brand names: Neo-NaClex-K, Centyl K.

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

Bendroflumethiazide, Potassium falls into 2 drug categories that Rhubarb can interact with; the most serious is rated moderate. Theoretically, long-term use of anthraquinones from rhubarb might increase the risk of nephrotoxicity when used with nephrotoxic drugs.

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

Rhubarb and Bendroflumethiazide, Potassium

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

Why Are There 2 Interactions?

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

Moderate

NEPHROTOXIC DRUGS

1 of 2

Why this applies to Bendroflumethiazide, Potassium

Bendroflumethiazide, Potassium falls under NEPHROTOXIC DRUGS — the group Rhubarb interacts with.

Theoretically, long-term use of anthraquinones from rhubarb might increase the risk of nephrotoxicity when used with nephrotoxic drugs.
The anthraquinone constituents of rhubarb have been shown to induce nephrotoxicity in animal research. Additionally, in a case report, a 23-year old female presented with kidney failure after taking 6 tablets of a proprietary slimming agent (found to contain the anthraquinones emodin and aloe-emodin from rhubarb) daily for 6 weeks and then adding diclofenac 25 mg 4 times daily for 2 days. The authors postulate that the anthraquinone constituents of rhubarb contributed to the renal dysfunction, and the addition of diclofenac, a nephrotoxic drug, led to renal failure. Until more is known, advise patients to avoid taking rhubarb if they are taking other potentially nephrotoxic drugs.
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 gist with rhubarb root and your Centyl K (bendroflumethiazide with potassium). This isn't about rhubarb changing how the drug is broken down. The concern is teamwork on your kidneys. Bendroflumethiazide is a water pill, and like other diuretics it can stress the kidneys, especially if you get dehydrated. Concentrated rhubarb root supplements contain anthraquinones that, in animal studies and one case report, have been linked to kidney harm.

So the worry is that long-term, high-dose rhubarb supplements stacked on a kidney-stressing medicine could add up. To be clear, this evidence is weak and largely theoretical, and eating rhubarb stalks in a pie is not the same as taking root capsules. Still, it's worth a quick chat with your doctor or pharmacist before starting a rhubarb supplement.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kwan TH, Tong MK, Leung KT, et al. Acute renal failure associated with prolonged intake of slimming pills containing anthraquinones. Hong Kong Med J 2006;12:394-7.
  2. Yan, M., Zhang, L. Y., Sun, L. X., Jiang, Z. Z., and Xiao, X. H. Nephrotoxicity study of total rhubarb anthraquinones on Sprague Dawley rats using DNA microarrays. J Ethnopharmacol. 4-15-2006; PubMed
Moderate

DIURETIC DRUGS

2 of 2

Bendroflumethiazide, Potassium also falls under DIURETIC DRUGS.

Theoretically, frequent and high doses of rhubarb might increase the risk of hypokalemia.
Rhubarb has stimulant laxative effects. Overuse of rhubarb might cause potassium depletion and compound diuretic-induced potassium loss.
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 know about your medication: bendroflumethiazide is a thiazide-type water pill that already tends to flush potassium out of your body, which is exactly why your tablet includes added potassium to help make up for that loss. Rhubarb root, when used regularly as a stimulant laxative, can pull even more potassium out through your gut. Stack those two together and your potassium could dip lower than intended.

Low potassium can leave you feeling tired, crampy, weak, or with an irregular heartbeat. To be fair, this is a theoretical concern based on how these things work, not strong proof, and a slice of rhubarb in a pie won't matter. It's the concentrated, frequent supplement doses to watch. Please check with your pharmacist or doctor before using rhubarb regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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

Rhubarb Also Interacts With Other Medications

Rhubarb has 657 moderate known drug interactions in our database — the Bendroflumethiazide, Potassium one above is among them. If you take anything else, check it against the full list below.

Moderate 657 No known interaction 2,173 (incl. Bendroflumethiazide, Potassium)
Taking anything else?

Check Another of Your Medications Against Rhubarb

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

From our Q&A

Questions About Rhubarb or Bendroflumethiazide, Potassium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Rhubarb or Bendroflumethiazide, Potassium, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Bendroflumethiazide, Potassium

This page covers Rhubarb only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Bendroflumethiazide, Potassium page lists 127 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Dolomite (major), Lithium (major) and Oleander (major).

By severity: 7 major · 103 moderate · 17 minor.

From our pharmacist’s overview on the Bendroflumethiazide, Potassium page

“Bendroflumethiazide with potassium (Neo-NaClex-K, Centyl K) is a water pill for blood pressure with built-in potassium replacement, and its interaction list warrants real care rather than a quick skim. Seven of the 127 supplement ingredients on file rate major, and they concentrate on two hazards: added kidney damage (Siberian cocklebu…”

Reviewed by 2 · Jul 18, 2026

Open the Bendroflumethiazide, Potassium interaction page

One more smart check

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

We hold 133 real supplement products containing Rhubarb, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rhubarb. Your product may carry other ingredients that interact with Bendroflumethiazide, Potassium too, on top of Rhubarb — 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 Rhubarb and Bendroflumethiazide, Potassium 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 Rhubarb
Top 25%

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

29 days ago today
Medication Bendroflumethiazide, Potassium
Top 25%

#353 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 Rhubarb

What is Rhubarb?

Rhubarb
  • Constipation
  • Digestive upset
  • Menopausal symptoms
  • Kidney and liver conditions (traditional)
  • Pancreatitis (hospital/traditional use)

Rhubarb root has a long history of use as a laxative and in traditional Chinese medicine, and its edible stalks are a common food. Most medicinal claims are backed by limited or low-quality evidence, and the root can cause cramping and diarrhea. The leaves are toxic and should never be eaten, and rhubarb supplements are best avoided in pregnancy and breastfeeding.

Read the full Rhubarb monograph & all interactions
Keep checking

Other Drugs & Rhubarb

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

0Major
657Moderate
0Minor
2,172No known interaction
657 Moderate 2,172 No interaction
Moderate

657 interactions

Showing 60 of 657 moderate interactions — see all 657 on the Rhubarb page.

No interaction 2,172 drugs checked — show the list

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

Showing the 60 most looked-up of 2,172 medications checked with no known interaction — see the full Rhubarb list.

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

Can you take Rhubarb with Bendroflumethiazide, Potassium?
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 Rhubarb and Bendroflumethiazide, Potassium?
Bendroflumethiazide, Potassium belongs to more than one drug category, and Rhubarb 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 Rhubarb and Bendroflumethiazide, Potassium 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.