Drug & supplement interaction

Slippery Elm + Isocarboxazid

Isocarboxazid brand name: Marplan.

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

Slippery Elm has a moderate interaction with Isocarboxazid. Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.

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

Slippery Elm and Isocarboxazid

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

Moderate

ORAL DRUGS

Why this applies to Isocarboxazid

Isocarboxazid falls under ORAL DRUGS — the group Slippery Elm interacts with.

Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.
Slippery elm inner bark contains mucilage, which may interfere with the absorption of orally administered 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 of it: slippery elm turns into a slick, gel-like fiber when it hits water, and that gel can coat your gut. The concern is that this coating might slow down or partly block how much isocarboxazid (Marplan) your body absorbs. If less of it gets in, your depression treatment could work less reliably over time.

I'll be honest, this is a theoretical worry based on how the herb behaves, not strong human studies, so don't panic. A simple fix is timing: take your isocarboxazid and the slippery elm a few hours apart so the gel isn't sitting on your medicine. Since MAO inhibitors are sensitive drugs with strict rules already, please run this by your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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

Slippery Elm Also Interacts With Other Medications

Slippery Elm has 2,021 moderate known drug interactions in our database — the Isocarboxazid one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,021 No known interaction 809 (incl. Isocarboxazid)
Taking anything else?

Check Another of Your Medications Against Slippery Elm

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

From our Q&A

Questions About Slippery Elm or Isocarboxazid

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Slippery Elm or Isocarboxazid, 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 Isocarboxazid

This page covers Slippery Elm only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Isocarboxazid page lists 81 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Bitter Orange (major), Brewer's Yeast (major) and Cowhage (major).

By severity: 14 major · 55 moderate · 12 minor.

From our pharmacist’s overview on the Isocarboxazid page

“Isocarboxazid (Marplan) is an MAOI antidepressant, and that drug class carries some of the sharpest supplement and food hazards in the pharmacy, so read this list closely rather than skimming it. Fourteen of the 81 entries rate major, and most of the danger runs through tyramine.”

Reviewed by 2 · Jul 18, 2026

Open the Isocarboxazid interaction page

One more smart check

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

We hold 1,490 real supplement products containing Slippery Elm, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Slippery Elm. Your product may carry other ingredients that interact with Isocarboxazid too, on top of Slippery Elm — 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 Slippery Elm and Isocarboxazid 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 Slippery Elm
Top 10%

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

29 days ago today
Medication Isocarboxazid
Steady interest

#2,436 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 Slippery Elm

What is Slippery Elm?

Slippery Elm
  • Sore throat and cough
  • Heartburn and acid reflux
  • Digestive upset and IBS
  • Skin irritation (topical)
  • Constipation or diarrhea

Slippery elm is a traditional herbal remedy made from the inner bark of a North American elm tree, used mainly to soothe sore throats and irritated digestive tracts. Its mucilage can coat and calm mucous membranes, but solid human evidence for most uses is limited. It is generally considered low-risk for short-term use, but you should still check with your pharmacist or doctor first.

Read the full Slippery Elm monograph & all interactions
Medication

About Isocarboxazid

What Is Isocarboxazid Used For?

Brand name: Marplan

Marplan (isocarboxazid) is indicated for the treatment of depression — specifically, major depressive disorder. Because it carries serious risks, it is not a first-choice antidepressant. Marplan is generally reserved for patients who have not responded adequately to other antidepressants.

Clinical trials showed Marplan to be effective in adult outpatients with major depressive disorder, including those whose depression was accompanied by anxiety symptoms such as panic or phobias. Marplan is not approved for use in children or adolescents.

See full Isocarboxazid drug information
Keep checking

Other Drugs & Slippery Elm

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

0Major
2,021Moderate
0Minor
808No known interaction
2,021 Moderate 808 No interaction
Moderate

2,021 interactions

Showing 60 of 2,021 moderate interactions — see all 2,021 on the Slippery Elm page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Slippery Elm list.

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

Can you take Slippery Elm with Isocarboxazid?
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 Slippery Elm and Isocarboxazid 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 Isocarboxazid and Slippery Elm?

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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.