Drug & supplement interaction

Khat + Isocarboxazid

Isocarboxazid brand name: Marplan.

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

Khat has a moderate interaction with Isocarboxazid. In one case report, a 24-year-old man developed reversible cerebral vasoconstriction syndrome (RCVS) thought to be caused by chewing khat in combination with treatment with tranylcypromine, an MAOI.

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

Khat and Isocarboxazid

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

Moderate

MONOAMINE OXIDASE INHIBITORS (MAOIs)

Why this applies to Isocarboxazid

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

In one case report, a 24-year-old man developed reversible cerebral vasoconstriction syndrome (RCVS) thought to be caused by chewing khat in combination with treatment with tranylcypromine, an MAOI. Theoretically, the combination of khat and an MAOI might increase the induction of sympathetic stimulation, increasing the risk of vasoconstriction. Until more is known, avoid khat in patients taking MAOIs and for 14 days after MAOI discontinuation.
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

First things first: khat is a stimulant that's illegal in the U.S., so I can't recommend using it at all. But here's why mixing it with Marplan (isocarboxazid) is especially worrying. Your MAOI works by slowing down the enzyme that breaks down norepinephrine and dopamine, so those brain chemicals build up. Khat does the opposite job from the other end, pushing your body to release even more of those same stimulating chemicals.

Put them together and you can get a dangerous pile-up: sharply rising blood pressure, racing heart, headache, and in one reported case, a syndrome where blood vessels in the brain clamp down. This is anecdotal (a single case report), so it's theoretical rather than proven, but the risk is serious enough to take seriously. Please don't combine them, including for 14 days after stopping Marplan, and talk with your doctor or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Tuladhar AM, Boogaarts HD, de Leeuw FE, van Dijk E. Reversible cerebral vasoconstriction syndrome after chewing khat leaves. Cerebrovasc Dis. 2013;36(2):158-9. PubMed

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

Khat Also Interacts With Other Medications

Khat has 4 major, 400 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 4 Moderate 400 No known interaction 2,426 (incl. Isocarboxazid)
Taking anything else?

Check Another of Your Medications Against Khat

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

Everything else you take

See Every Supplement That Interacts With Isocarboxazid

This page covers Khat 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

How much people look this up

Where Khat 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 Khat
Top half

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

29 days ago today
Medication Isocarboxazid
Steady interest

#2,035 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 Khat

What is Khat?

Khat
  • Stimulant for energy and alertness
  • Euphoria and mood elevation
  • Reducing fatigue
  • Appetite suppression
  • Social and traditional ceremonies

Khat is a plant chewed for its amphetamine-like stimulant effects, but it carries serious risks including high blood pressure, heart problems, mental health effects, and dependence. It is a controlled substance and illegal in the United States and many other countries, so it should not be used.

Read the full Khat 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 & Khat

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

4Major
400Moderate
0Minor
2,425No known interaction
4 Major 400 Moderate 2,425 No interaction
Major

4 interactions

Moderate

400 interactions

Showing 60 of 400 moderate interactions — see all 400 on the Khat page.

No interaction 2,425 drugs checked — show the list

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

Showing the 60 most looked-up of 2,425 medications checked with no known interaction — see the full Khat list.

See the full Khat 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
Khat 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 Khat and Isocarboxazid Together: Common Questions

Can you take Khat 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 Khat 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 Khat?

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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.