Drug & supplement interaction

Catechu + Estramustine Phosphate Sodium

Estramustine Phosphate Sodium brand name: Emcyt.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Catechu and Estramustine Phosphate Sodium in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Catechu and Estramustine Phosphate Sodium

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Estramustine Phosphate Sodium and Catechu in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Catechu safety at a glance

Catechu overall Use caution Likely fine for short-term use in food-like amounts, but human safety data on concentrated supplements are limited.
Pregnancy Avoid Not enough reliable safety information, so it is best avoided during pregnancy.
Breastfeeding Likely Safe When used orally in amounts commonly found in foods. Catechu has Generally Recognized As Safe (GRAS) status for use in foods in the US. There is insufficient re... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Estramustine Phosphate Sodium and Catechu? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Estramustine Phosphate Sodium

Interactions in our licensed database are recorded against drug classes, not just single drug names. Estramustine Phosphate Sodium is filed under 2 classifications — alkylating agents, oral drugs. Catechu has documented interactions with 4 drug classes — the most serious being antihypertensive drugs (moderate), cytochrome p450 1a2 (cyp1a2) substrates (moderate) and immunosuppressants (moderate) — and none of Estramustine Phosphate Sodium’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Catechu Does Interact With Other Medications

Catechu has 475 moderate known drug interactions in our database — Estramustine Phosphate Sodium isn’t one of them. If you take anything else, check it against the full list below.

Moderate 475 No known interaction 2,355 (incl. Estramustine Phosphate Sodium)
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.

What to actually watch for

What Catechu Itself Has Been Linked To

This is not an interaction — nothing below involves Estramustine Phosphate Sodium. It is the side-effect record for Catechu on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Catechu, this list is the first place to look. 2 entries are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes / Liver problems Worth acting on Additional detail

    “A specific combination product (Limbrel, Primus Pharmaceuticals) containing flavocoxid, a mixture of flavonoid extracts from catechu and Baikal skullcap, has been linked to several reports of acute liver damage. In a case series, four reports of liver damage were described in patients taking this product. The patients involved were females aged 54-68 years taking doses of 250-500 mg twice daily for 1-3 months.”

    Catechu · Natural Medicines adverse-effect record, reported in hepatitis.

    5 sources cited
    1. 18009. Chalasani N, Vuppalanchi R, Navarro V, et al. Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series. Ann Intern Med 2012;156:857-60. PubMed
    2. 18011. PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
    3. 18010. Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5. PubMed
    4. 106042. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot
    5. 94563. Papafragkakis C, Ona MA, Reddy M, et al. Acute hepatitis after ingestion of a preparation of chinese skullcap and black catechu for joint pain. Case Reports Hepatol 2016;2016:4356749. PubMed
  • Shortness of breath / An allergic reaction Worth acting on Additional detail

    “A specific combination product (Limbrel, Primus Pharmaceuticals) containing flavocoxid, a mixture of flavonoid extracts from catechu and Baikal skullcap, has been linked to several reports of hypersensitivity pneumonitis. Symptoms include fever, chills, headache, cough, chronic bronchitis, shortness of breath, weight loss, and fatigue.”

    Catechu · Natural Medicines adverse-effect record, reported in acute bronchitis.

    1 source cited
    1. 106042. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot
  • Weight loss / Chills / Cough Additional detail

    Recorded for Catechu in the same Natural Medicines adverse-effect record shown under Shortness of breath / An allergic reaction above.

  • Fever Additional detail

    Recorded for Catechu in the same Natural Medicines adverse-effect record shown under Shortness of breath / An allergic reaction above.

  • Itching / Stomach pain Additional detail

    Recorded for Catechu in the same Natural Medicines adverse-effect record shown under Yellowing of the skin or eyes / Liver problems above.

Showing the 10 most notable of 13 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Catechu — expand a row for the licensed statement it rests on. We haven’t matched Estramustine Phosphate Sodium to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Estramustine Phosphate Sodium.

Special populations

Catechu in Pregnancy & Breastfeeding

Lactation Likely Safe

When used orally in amounts commonly found in foods. Catechu has Generally Recognized As Safe (GRAS) status for use in foods in the US. There is insufficient reliable information available about the safety of catechu when used orally in medicinal amounts or when used topically during pregnancy and lactation.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Estramustine Phosphate Sodium

This page covers Catechu only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Estramustine Phosphate Sodium page lists 24 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Acerola (moderate), Alpha-lipoic Acid (moderate), Coenzyme Q10 (moderate) and Coffee Charcoal (moderate).

By severity: 1 major · 14 moderate · 9 minor.

From our pharmacist’s overview on the Estramustine Phosphate Sodium page

“Estramustine phosphate sodium (Emcyt) is an oral chemotherapy for advanced prostate cancer, so supplements that weaken it carry real weight, and this list of 24 ingredients warrants genuine care. Nearly everything here does one of two things: fiber-heavy products like psyllium and various gums can keep the capsule from being absorbed p…”

Reviewed by 2 · Jul 18, 2026

Open the Estramustine Phosphate Sodium 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. Even though Catechu itself has no known interaction with Estramustine Phosphate Sodium, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Catechu and Estramustine Phosphate Sodium 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

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

29 days ago today
Medication Estramustine Phosphate Sodium
Top half

#1,261 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Catechu reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Catechu and Estramustine Phosphate Sodium records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
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.

Senegalia catechu · Fabaceae · Heartwood (and the extract/gum made from it) · Extract, powder, lozenges, mouth rinses, topical preparations, and as an ingredient in some herbal blends

An interaction check asks whether these two react with each other — it does not ask whether Catechu is a good idea for someone in your situation. Here is what our Catechu record says about it on its own.

Catechu: dosing

There is no well-established, standardized dose of catechu for any health condition. Products vary widely in strength and form, from lozenges and mouth rinses to powders and capsules.The safest approach is to follow the directions on the product label and not exceed them. Avoid using concentrated extracts for long periods without professional guidance.

From our Catechu monograph — the full record covers uses, side effects and every documented interaction.

Read the full Catechu monograph & all interactions
Medication

About Estramustine

What Is Estramustine Used For?

Brand name: Emcyt

  • Estramustine is used to treat prostate cancer that has worsened or has spread to other parts of the body. Estramustine is in a class of medications called antimicrotubule agents. It works by stopping the growth and spread of cancer cells.

See full Estramustine 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
475Moderate
0Minor
2,354No known interaction
475 Moderate 2,354 No interaction
Moderate

475 interactions

Showing 60 of 475 moderate interactions — see all 475 on the Catechu page.

No interaction 2,354 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 2,354 medications checked with no known interaction — see the full Catechu list.

See the full Catechu interactions page
See every supplement checked against Estramustine Phosphate Sodium, ranked by severity
Evidence & sources

Catechu References

The 9 references that drive our Catechu monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  2. Sham JS, Chiu KW, Pang PK. Hypotensive action of Acacia catechu. Planta Med 1984;50:177-80.
  3. Chalasani N, Vuppalanchi R, Navarro V, et al. Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series. Ann Intern Med 2012;156:857-60. PubMed
  4. Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5. PubMed
  5. PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
  6. Al-Mohizea AM, Raish M, Ahad A, et al. Pharmacokinetic interaction of Acacia catechu with CYP1A substrate theophylline in rabbits. J Tradit Chin Med 2015;35(5):588-93. PubMed
  7. Papafragkakis C, Ona MA, Reddy M, et al. Acute hepatitis after ingestion of a preparation of chinese skullcap and black catechu for joint pain. Case Reports Hepatol 2016;2016:4356749. PubMed
  8. Sunil MA, Sunitha VS, Ashitha A, et al. Catechin rich butanol fraction extracted from Acacia catechu L. (a thirst quencher) exhibits immunostimulatory potential. J Food Drug Anal. 2019;27(1):195-207. PubMed
  9. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Catechu and Estramustine Phosphate Sodium Together: Common Questions

Is it safe to take Catechu with Estramustine Phosphate Sodium?
We do not list a known interaction between Catechu and Estramustine Phosphate Sodium. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Catechu and Estramustine Phosphate Sodium combination checked?
Interactions in our licensed database are recorded against drug classes. Estramustine Phosphate Sodium is filed under 2 classifications, and Catechu has documented interactions with 4 drug classes — none of Estramustine Phosphate Sodium's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Catechu interact with any other medications?
Yes. Catechu has 475 documented drug interactions in our database — Estramustine Phosphate Sodium is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Estramustine Phosphate Sodium interact with any supplements?
Yes. Estramustine Phosphate Sodium has documented interactions with 24 supplements in our database — Catechu is not one of them. The Estramustine Phosphate Sodium interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Catechu monograph Uses, safety profile, and every drug interaction in one place Estramustine drug information The full plain-English guide to this medication Estramustine Phosphate Sodium supplement interactions Every supplement checked against Estramustine Phosphate Sodium, 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 References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Estramustine Phosphate Sodium 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.