Drug & supplement interaction

Epistane + Methenamine Mandelate

Methenamine Mandelate brand names: Mandelamine, Methimazole.

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

Epistane has a moderate interaction with Methenamine Mandelate. Theoretically, concomitant use might have additive adverse hepatotoxic effects.

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

Epistane and Methenamine Mandelate

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

Moderate

HEPATOTOXIC DRUGS

Why this applies to Methenamine Mandelate

Methenamine Mandelate falls under HEPATOTOXIC DRUGS — the group Epistane interacts with.

Theoretically, concomitant use might have additive adverse hepatotoxic effects.
Epistane is an anabolic androgenic steroid, and more specifically a 17-alpha-alkylated androgen. Therefore, there is concern that epistane has hepatotoxic effects. Also, epistane is structurally similar to epitiostanol, which has been associated with hepatotixicity in a case series of four patients.
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 concern with pairing these two: Epistane is a methylated anabolic steroid that's known to be hard on the liver. The medication you asked about can also put some stress on the liver in certain people. Put them together and you may be stacking two liver burdens at once, which is what the interaction warns about.

Honestly, I want to flag something first. The brand name listed (Methimazole, for an overactive thyroid) doesn't match Methenamine Mandelate, a urinary antiseptic. Either way, this interaction is theoretical, based on how the drugs behave rather than real case reports, so it isn't a proven problem. Still, watch for yellowing skin, dark urine, belly pain, or unusual fatigue, and please talk with your doctor or pharmacist before combining them. I'd also strongly steer you away from Epistane entirely.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rahnema CD, Crosnoe LE, Kim ED. Designer steroids - over-the-counter supplements and their androgenic component: review of an increasing problem. Andrology. 2015;3(2):150-5. PubMed
  2. Díaz FC, Sáez-González E, Benlloch S, et al. Albumin dialysis with MARS for the treatment of anabolic steroid-induced cholestasis. Ann Hepatol. 2016;15(6):939-943.

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

Epistane Also Interacts With Other Medications

Epistane has 369 moderate known drug interactions in our database — the Methenamine Mandelate one above is one of them. If you take anything else, check it against the full list below.

Moderate 369 No known interaction 2,461 (incl. Methenamine Mandelate)
Taking anything else?

Check Another of Your Medications Against Epistane

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

Everything else you take

See Every Supplement That Interacts With Methenamine Mandelate

This page covers Epistane only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methenamine Mandelate page lists 91 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Ascophyllum Nodosum (moderate).

By severity: 4 major · 77 moderate · 10 minor.

From our pharmacist’s overview on the Methenamine Mandelate page

“People take methenamine mandelate (Mandelamine) day after day to keep urinary tract infections at bay, and that long habit is exactly why the 91 supplements on this page deserve genuine vigilance. Four carry a major rating, and most of those point at the liver: Siberian cocklebur has been linked to outright liver failure, and heavy bee…”

Reviewed by 2 · Jul 18, 2026

Open the Methenamine Mandelate interaction page

One more smart check

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

We hold 32 real supplement products containing Epistane, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Epistane. Your product may carry other ingredients that interact with Methenamine Mandelate too, on top of Epistane — 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 Epistane and Methenamine Mandelate 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 Epistane
Top half

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

29 days ago today
Medication Methenamine Mandelate
Top half

#1,304 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 Epistane

What is Epistane?

  • Building muscle mass
  • Increasing strength
  • Cutting or losing body fat
  • Bodybuilding cycles

Epistane is a synthetic anabolic steroid (a methylated 'designer steroid'), not a true dietary supplement or herb, even though it has been sold as a 'prohormone.' It is liver-toxic, can disrupt your natural hormones, and is illegal to sell as a supplement in the US under the Designer Anabolic Steroid Control Act. We strongly recommend avoiding it and talking with a doctor or pharmacist.

Read the full Epistane monograph & all interactions
Medication

About Methimazole

What Is Methimazole Used For?

Brand names: Mandelamine, Methimazole

Methimazole tablets are used in adults and children with hyperthyroidism (an overactive thyroid) due to Graves' disease or toxic multinodular goiter when surgery or radioactive iodine is not the right option. They work to lower thyroid hormone levels and ease symptoms.

Methimazole tablets are also used to bring thyroid hormone levels down before a patient undergoes thyroidectomy (thyroid surgery) or radioactive iodine treatment, making those procedures safer.

See full Methimazole drug information
Keep checking

Other Drugs & Epistane

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

0Major
369Moderate
0Minor
2,460No known interaction
369 Moderate 2,460 No interaction
Moderate

369 interactions

Showing 60 of 369 moderate interactions — see all 369 on the Epistane page.

No interaction 2,460 drugs checked — show the list

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

Showing the 60 most looked-up of 2,460 medications checked with no known interaction — see the full Epistane list.

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

Can you take Epistane with Methenamine Mandelate?
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 Epistane and Methenamine Mandelate 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 Methenamine Mandelate and Epistane?

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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.