Drug & supplement interaction

Iboga + diphenhydramine, calamine

diphenhydramine, calamine brand names: Caladryl cream, Caladryl lotion.

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

Iboga has a moderate interaction with diphenhydramine, calamine. Theoretically, taking iboga with CYP2D6 inhibitors might increase the levels and clinical effects of ibogaine.

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

Iboga and diphenhydramine, calamine

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) INHIBITORS

Why this applies to diphenhydramine, calamine

diphenhydramine, calamine falls under CYTOCHROME P450 2D6 (CYP2D6) INHIBITORS — the group Iboga interacts with.

Theoretically, taking iboga with CYP2D6 inhibitors might increase the levels and clinical effects of ibogaine.
Ibogaine, the active constituent of iboga, is a substrate of CYP2D6. One pharmacokinetic study shows that taking the CYP2D6 inhibitor paroxetine prior to taking ibogaine 20 mg increases the exposure to ibogaine and its metabolite noribogaine by 2-fold when compared with ibogaine alone.
Severity Moderate Likelihood Possible Evidence B

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 thing about this combo: it's the Iboga that gets affected, not your Caladryl. Diphenhydramine (the antihistamine in Caladryl) can mildly block an enzyme called CYP2D6, and that's the same enzyme your body uses to clear ibogaine. So in theory, ibogaine could build up and hit harder. One study found a known CYP2D6 blocker roughly doubled ibogaine exposure.

Honestly, my bigger concern is Iboga itself. It's illegal in the U.S. and has caused dangerous heart rhythm problems and deaths. I'd steer clear of it entirely. As for Caladryl, when you dab it on an itchy rash, very little gets into your bloodstream, so a lotion isn't likely to drive a major interaction. Please talk with your pharmacist or doctor before mixing anything with Iboga.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Henstra M, Wong L, Chahbouni A, et al. Toxicokinetics of ibogaine and noribogaine in a patient with prolonged multiple cardiac arrhythmias after ingestion of internet purchased ibogaine. Clin Toxicol (Phila). 2017;55(6):600-602. PubMed
  2. Glue P, Winter H, Garbe K, et al. Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20?mg dose of ibogaine in healthy volunteers. J Clin Pharmacol. 2015;55(6):680-7. PubMed
  3. Rodriguez P, Urbanavicius J, Prieto JP, et al. A single administration of the atypical psychedelic ibogaine or its metabolite noribogaine induces an antidepressant-like effect in rats. ACS Chem Neurosci 2020;11(11):1661-1672. 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 diphenhydramine, calamine 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. diphenhydramine, calamine)
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.

Everything else you take

See Every Supplement That Interacts With diphenhydramine, calamine

This page covers Iboga only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the diphenhydramine, calamine page lists 6 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Dimethylsulfoxide (dmso) (moderate), Fever Bark (moderate), Turpentine Oil (moderate), Yohimbe (moderate) and Alchemilla (minor).

By severity: 5 moderate · 1 minor.

From our pharmacist’s overview on the diphenhydramine, calamine page

“Yohimbe is the entry I would read first. Diphenhydramine, the itch-relieving antihistamine in Caladryl cream and lotion, blocks a liver enzyme called CYP2D6, and yohimbine, the active compound in yohimbe bark, needs that enzyme to leave the body, so its levels and side effects can climb.”

Reviewed by 2 · Jul 18, 2026

Open the diphenhydramine, calamine interaction page

How much people look this up

Where Iboga and diphenhydramine, calamine 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

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

29 days ago today
Medication diphenhydramine, calamine
Top 25%

#442 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
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 diphenhydramine, calamine, 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 diphenhydramine, calamine supplement interactions › Every supplement checked against diphenhydramine, calamine, ranked by severity 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 diphenhydramine, calamine Together: Common Questions

Can you take Iboga with diphenhydramine, calamine?
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 diphenhydramine, calamine 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 diphenhydramine, calamine and Iboga?

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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.