Drug & supplement interaction

Iboga + Chlorpheniramine Maleate, Dextromethorphan Hydrobromide

Chlorpheniramine Maleate, Dextromethorphan Hydrobromide brand names: Coricidin HBP Cough & Cold, Coricidin II Cough & Cold, Pediatric Vicks Formula 44m Cough & Cold Relief.

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

Chlorpheniramine Maleate, Dextromethorphan Hydrobromide falls into 3 drug categories that Iboga can interact with; the most serious is rated moderate. Theoretically, taking iboga with serotonergic drugs might increase levels of serotonin, resulting in additive effects with serotonergic drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Iboga and Chlorpheniramine Maleate, Dextromethorphan Hydrobromide

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Iboga interacts with whole categories of medication. Chlorpheniramine Maleate, Dextromethorphan Hydrobromide falls into 3 of those categories, so it can interact with Iboga in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

SEROTONERGIC DRUGS

1 of 3

Why this applies to Chlorpheniramine Maleate, Dextromethorphan Hydrobromide

Chlorpheniramine Maleate, Dextromethorphan Hydrobromide falls under SEROTONERGIC DRUGS — the group Iboga interacts with.

Theoretically, taking iboga with serotonergic drugs might increase levels of serotonin, resulting in additive effects with serotonergic drugs.
Ibogaine, a constituent in iboga, has serotonergic effects. Theoretically, combining serotonergic drugs with iboga might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders. Monitor patients for signs of serotonin syndrome and other serotonergic side effects if using iboga with serotonergic 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

The combo you're asking about pairs an antihistamine (chlorpheniramine) with the cough suppressant dextromethorphan. The piece that matters here is the dextromethorphan, which gently nudges serotonin levels in the brain. Iboga, through its main compound ibogaine, also pushes serotonin upward. Stack the two and you could, in theory, get too much serotonin activity at once.

If that happened, watch for signs like agitation, a racing heart, sweating, shivering, muscle twitching, or confusion (what's called serotonin syndrome). I'll be honest though: this warning is theoretical, based on how these substances work rather than real-world reports. Separately, ibogaine carries its own serious heart-rhythm risks. Please don't mix these without talking to your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Glick SD, Maisonneuve IS. Mechanisms of antiaddictive actions of ibogaine. Ann N Y Acad Sci 1998;844:214-26.
  2. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  3. Litjens RP, Brunt TM. How toxic is ibogaine? Clin Toxicol (Phila). 2016;54(4):297-302. PubMed
Moderate

ANTICHOLINERGIC DRUGS

2 of 3

Chlorpheniramine Maleate, Dextromethorphan Hydrobromide also falls under ANTICHOLINERGIC DRUGS.

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 one. The chlorpheniramine part of your cough and cold product is an antihistamine that works partly by blocking acetylcholine, a messenger in the body. Lab studies suggest Iboga might raise acetylcholine levels, which could theoretically push back against chlorpheniramine and make it a little less effective at drying things up. In real terms, you might notice less relief from a runny nose or sneezing.

I want to be honest that this is very weak, test-tube level evidence, and the main Iboga compound (ibogaine) didn't even show this effect. Far more important is that Iboga itself is dangerous and illegal here, with known heart rhythm risks. Dextromethorphan also affects serotonin, so combining the two raises other safety concerns. Please talk with your pharmacist or doctor before mixing anything like this.

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
Moderate

CYTOCHROME P450 2D6 (CYP2D6) INHIBITORS

3 of 3

Chlorpheniramine Maleate, Dextromethorphan Hydrobromide also falls under CYTOCHROME P450 2D6 (CYP2D6) INHIBITORS.

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 to know about this combo: that cough and cold product (Coricidin) contains chlorpheniramine and dextromethorphan, and both of those gently block a liver enzyme called CYP2D6. Iboga's active ingredient, ibogaine, is broken down by that same enzyme. So if you slow the enzyme down, ibogaine can build up to higher levels in your body. One small study found that blocking CYP2D6 roughly doubled ibogaine exposure.

Why that matters: ibogaine already carries serious heart rhythm risks, and pushing its levels higher could make those dangers worse. Honestly, my bigger concern is that ibogaine is illegal in the U.S. and not safe outside tightly controlled research. Please don't combine these, and talk with your pharmacist or doctor if you have questions.

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 Chlorpheniramine Maleate, Dextromethorphan Hydrobromide one above is among them. If you take anything else, check it against the full list below.

Major 1 Moderate 500 No known interaction 2,329 (incl. Chlorpheniramine Maleate, Dextromethorphan Hydrobromide)
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 Chlorpheniramine Maleate, Dextromethorphan Hydrobromide

This page covers Iboga only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine Maleate, Dextromethorphan Hydrobromide page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Henbane (major), Lithium (major) and Scopolia (major).

By severity: 6 major · 170 moderate · 42 minor.

From our pharmacist’s overview on the Chlorpheniramine Maleate, Dextromethorphan Hydrobromide page

“Grapefruit is the interaction I would flag first for anyone taking chlorpheniramine with dextromethorphan (Coricidin HBP Cough & Cold). It blocks the enzyme that clears these ingredients, so levels and side effects can climb.”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine Maleate, Dextromethorphan Hydrobromide interaction page

How much people look this up

Where Iboga and Chlorpheniramine Maleate, Dextromethorphan Hydrobromide 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

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

29 days ago today
Medication Chlorpheniramine Maleate, Dextromethorphan Hydrobromide
Top 5%

#119 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 Chlorpheniramine Maleate, Dextromethorphan Hydrobromide, 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 Chlorpheniramine Maleate, Dextromethorphan Hydrobromide supplement interactions › Every supplement checked against Chlorpheniramine Maleate, Dextromethorphan Hydrobromide, 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 Chlorpheniramine Maleate, Dextromethorphan Hydrobromide Together: Common Questions

Can you take Iboga with Chlorpheniramine Maleate, Dextromethorphan Hydrobromide?
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.
Why are there 3 interactions listed for Iboga and Chlorpheniramine Maleate, Dextromethorphan Hydrobromide?
Chlorpheniramine Maleate, Dextromethorphan Hydrobromide belongs to more than one drug category, and Iboga interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Iboga and Chlorpheniramine Maleate, Dextromethorphan Hydrobromide 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

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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.