Drug & supplement interaction

Iboga + Clemastine

Clemastine brand name: Tavist Allergy.

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

Iboga has a moderate interaction with Clemastine. Theoretically, iboga might decrease the effectiveness of anticholinergic drugs.

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

Iboga and Clemastine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Clemastine

Clemastine falls under ANTICHOLINERGIC DRUGS — the group Iboga interacts with.

Theoretically, iboga might decrease the effectiveness of anticholinergic drugs.
In vitro research shows that iboga can inhibit acetylcholinesterase and might increase acetylcholine levels. However, the constituent ibogaine does not appear to have this effect.
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 idea behind this pairing. Clemastine works by blocking histamine, and it also has drying (anticholinergic) effects, which is why it can cause dry mouth, blurry vision, constipation, and drowsiness. Some lab studies suggest Iboga might raise levels of acetylcholine, a brain and body messenger. Since clemastine's drying action partly works by opposing acetylcholine, more acetylcholine could, in theory, push back against the drug and make it work a little less well for your allergy symptoms.

I'll be honest with you: this is a theoretical concern based on test-tube research, and the main active compound in Iboga (ibogaine) didn't show this effect. Beyond that, Iboga carries serious heart and safety risks and isn't something I'd recommend. If you're considering it, please talk with your doctor or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Alper K, Reith ME, Sershen H. Ibogaine and the inhibition of acetylcholinesterase. J Ethnopharmacol. 2012;139(3):879-82. 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

Iboga Also Interacts With Other Medications

Iboga has 1 major, 500 moderate known drug interactions in our database — the Clemastine one above is one of them. If you take anything else, check it against the full list below.

Major 1 Moderate 500 No known interaction 2,329 (incl. Clemastine)
Taking anything else?

Check Another of Your Medications Against Iboga

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

From our Q&A

Questions About Iboga or Clemastine

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

This page covers Iboga only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clemastine page lists 72 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 12 minor.

From our pharmacist’s overview on the Clemastine page

“Clemastine (Tavist Allergy) is an older, sedating antihistamine that already dries the mouth, blurs vision, and slows the gut, and that is exactly why this list earns real caution rather than a quick skim. Thirty of the 72 supplements on file pile the same drying, sedating anticholinergic load on top, and two of the three major-rated e…”

Reviewed by 2 · Jul 18, 2026

Open the Clemastine interaction page

How much people look this up

Where Iboga and Clemastine 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 Iboga
Top half

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

29 days ago today
Medication Clemastine
Steady interest

#2,561 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 Iboga

What is Iboga?

Iboga
  • Drug and alcohol addiction
  • Opioid withdrawal
  • Spiritual and ceremonial rituals
  • Fatigue and stimulant effects
  • Mood and emotional issues

Iboga is a Central African shrub whose root bark contains ibogaine, a powerful hallucinogenic compound studied mainly for addiction. It carries serious safety risks, including dangerous heart rhythm changes and deaths, and ibogaine is illegal in the United States and many other countries. We do not recommend its use outside of tightly controlled research settings.

Read the full Iboga monograph & all interactions
Medication

About Clemastine

What Is Clemastine Used For?

Brand name: Tavist Allergy

Clemastine treats symptoms of allergic rhinitis (hay fever and similar nasal allergies) — including sneezing, runny nose, itching, and watery eyes. The oral solution (Clemastine Fumarate syrup) is indicated for adults and children aged 6 through 12 years. The tablets (Clemastine Fumarate and Clemsza) are indicated for adults.

Clemastine also treats mild, uncomplicated allergic skin reactions — specifically urticaria (hives) and angioedema (swelling under the skin) — at the appropriate dosage level, in both the oral solution and tablet forms.

See full Clemastine drug information
Keep checking

Other Drugs & Iboga

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

1Major
500Moderate
0Minor
2,328No known interaction
1 Major 500 Moderate 2,328 No interaction
Major

1 interaction

Moderate

500 interactions

Showing 60 of 500 moderate interactions — see all 500 on the Iboga page.

No interaction 2,328 drugs checked — show the list

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

Showing the 60 most looked-up of 2,328 medications checked with no known interaction — see the full Iboga list.

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

Can you take Iboga with Clemastine?
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 Iboga and Clemastine 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 Clemastine and Iboga?

Our pharmacists answer your medication & supplement questions — free.

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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.