Drug & supplement interaction

Scotch Broom + Isocarboxazid

Isocarboxazid brand name: Marplan.

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

Scotch Broom has a major interaction with Isocarboxazid. Scotch broom flower contains tyramine. Combined use with MAOIs might cause a hypertensive crisis.

Read the full interaction report
SeverityMajor
LikelihoodProbable
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Scotch Broom and Isocarboxazid

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

Major

MONOAMINE OXIDASE INHIBITORS (MAOIs)

Why this applies to Isocarboxazid

Isocarboxazid falls under MONOAMINE OXIDASE INHIBITORS (MAOIs) — the group Scotch Broom interacts with.

Scotch broom flower contains tyramine. Combined use with MAOIs might cause a hypertensive crisis.
Severity Major Likelihood Probable Evidence D

Interaction 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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the concern with this pairing. Isocarboxazid (Marplan) is an MAO inhibitor, and one of its biggest cautions is its sensitivity to a compound called tyramine. Normally your body breaks tyramine down, but Marplan blocks that cleanup. When tyramine builds up, it can trigger a sudden, dangerous spike in blood pressure known as a hypertensive crisis, which can come with a pounding headache, neck stiffness, sweating, chest pain, or a racing heart.

Scotch Broom flower is reported to contain tyramine, so combining it with Marplan could set off that reaction. This is based on how these substances behave rather than lots of case reports, but the risk is serious enough that I would steer clear. Please check with your pharmacist or doctor before using any Scotch Broom product while on Marplan.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 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

Scotch Broom Also Interacts With Other Medications

Scotch Broom has 10 major, 1 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.

Major 10 Moderate 1 No known interaction 2,819 (incl. Isocarboxazid)
Taking anything else?

Check Another of Your Medications Against Scotch Broom

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

Everything else you take

See Every Supplement That Interacts With Isocarboxazid

This page covers Scotch Broom 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 Scotch Broom as Part of a Dietary Supplement Product? Check It for Interactions

We hold 6 real supplement products containing Scotch Broom, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Scotch Broom. Your product may carry other ingredients that interact with Isocarboxazid too, on top of Scotch Broom — 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 Scotch Broom 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 Scotch Broom
Top 25%

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

29 days ago today
Medication Isocarboxazid
Steady interest

#2,535 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 Scotch Broom

What is Scotch Broom?

  • Heart rhythm and circulation complaints
  • Diuretic (increasing urine)
  • Heavy menstrual bleeding
  • Mild swelling
  • Traditional folk remedy

Scotch Broom is a flowering shrub that has been used in folk medicine for heart and circulation complaints, but it contains potentially toxic alkaloids and there is no solid scientific evidence that it works for any condition. Because it can affect heart rate and blood pressure and may be dangerous in higher amounts, most people should avoid it, and it should never be used during pregnancy or breastfeeding. Always talk with a pharmacist or doctor before trying it.

Read the full Scotch Broom 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 & Scotch Broom

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

10Major
1Moderate
0Minor
2,818No known interaction
10 Major 1 Moderate 2,818 No interaction
Major

10 interactions

Moderate

1 interaction

No interaction 2,818 drugs checked — show the list

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

Showing the 60 most looked-up of 2,818 medications checked with no known interaction — see the full Scotch Broom list.

See the full Scotch Broom 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
Scotch Broom 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 Scotch Broom and Isocarboxazid Together: Common Questions

Can you take Scotch Broom with Isocarboxazid?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Scotch Broom and Isocarboxazid interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Isocarboxazid and Scotch Broom?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.