Drug & supplement interaction

Castor Bean + Hydrochlorothiazide, Propranolol

Hydrochlorothiazide, Propranolol brand name: Inderide.

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

Castor Bean has a moderate interaction with Hydrochlorothiazide, Propranolol. Theoretically, castor oil might increase the risk of hypokalemia when taken with diuretic drugs.

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

Castor Bean and Hydrochlorothiazide, Propranolol

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

Moderate

DIURETIC DRUGS

Why this applies to Hydrochlorothiazide, Propranolol

Hydrochlorothiazide, Propranolol falls under DIURETIC DRUGS — the group Castor Bean interacts with.

Theoretically, castor oil might increase the risk of hypokalemia when taken with diuretic drugs.
There is some concern that overuse of castor oil might 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 Inderide: it pairs a water pill (hydrochlorothiazide) with a beta blocker (propranolol). That water pill already tends to flush potassium out of your body. Castor oil is a stimulant laxative, and when used too much or too often, it can cause its own potassium loss through repeated diarrhea. Stacked together, the worry is that your potassium could drop lower than it should.

Low potassium can leave you feeling tired, crampy, weak, or with an irregular heartbeat. I'll be honest, this is a theoretical concern based on how both work, not something proven, and occasional, as-directed castor oil use is unlikely to cause trouble. Still, if you rely on Inderide daily, check with your pharmacist or doctor before using castor oil regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 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

Castor Bean Also Interacts With Other Medications

Castor Bean has 74 moderate known drug interactions in our database — the Hydrochlorothiazide, Propranolol one above is one of them. If you take anything else, check it against the full list below.

Moderate 74 No known interaction 2,756 (incl. Hydrochlorothiazide, Propranolol)
Taking anything else?

Check Another of Your Medications Against Castor Bean

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

Everything else you take

See Every Supplement That Interacts With Hydrochlorothiazide, Propranolol

This page covers Castor Bean only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydrochlorothiazide, Propranolol page lists 324 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: 11 major · 273 moderate · 40 minor.

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

“Inderide combines hydrochlorothiazide, a water pill, with propranolol, a beta blocker, so a supplement that also lowers blood pressure or pulls potassium out of the body hits the drug on its own turf. That describes most of this list, and I'd approach it with genuine care.”

Reviewed by 2 · Jul 18, 2026

Open the Hydrochlorothiazide, Propranolol interaction page

How much people look this up

Where Castor Bean and Hydrochlorothiazide, Propranolol 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 Castor Bean
Steady interest

#1,451 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Hydrochlorothiazide, Propranolol
Steady interest

#1,495 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 Castor Bean

What is Castor Bean?

  • Constipation relief
  • Skin and hair care
  • Labor induction (folk use)
  • Topical anti-inflammatory packs
  • Joint and muscle massage

Castor bean is the source of castor oil, a well-known stimulant laxative, but the raw seeds contain ricin, a potent and potentially deadly poison. The processed oil is generally considered safe when used as directed, while the whole or chewed seeds should never be eaten. Always talk to a pharmacist or doctor before using castor oil, especially during pregnancy or for children.

Read the full Castor Bean monograph & all interactions
Keep checking

Other Drugs & Castor Bean

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

0Major
74Moderate
0Minor
2,755No known interaction
74 Moderate 2,755 No interaction
Moderate

74 interactions

Showing 60 of 74 moderate interactions — see all 74 on the Castor Bean page.

No interaction 2,755 drugs checked — show the list

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

Showing the 60 most looked-up of 2,755 medications checked with no known interaction — see the full Castor Bean list.

See the full Castor Bean interactions page
See every supplement checked against Hydrochlorothiazide, Propranolol, 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
Castor Bean monograph › Uses, safety, and every drug interaction in one place Hydrochlorothiazide, Propranolol supplement interactions › Every supplement checked against Hydrochlorothiazide, Propranolol, 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 Castor Bean and Hydrochlorothiazide, Propranolol Together: Common Questions

Can you take Castor Bean with Hydrochlorothiazide, Propranolol?
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 Castor Bean and Hydrochlorothiazide, Propranolol 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 Hydrochlorothiazide, Propranolol and Castor Bean?

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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.