Drug & supplement interaction

Iboga + Chlorpheniramine, Pheylephrine, Pyrilamine

Chlorpheniramine, Pheylephrine, Pyrilamine brand name: Phena-Plus.

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

Chlorpheniramine, Pheylephrine, Pyrilamine 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, Pheylephrine, Pyrilamine

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, Pheylephrine, Pyrilamine 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, Pheylephrine, Pyrilamine

Chlorpheniramine, Pheylephrine, Pyrilamine 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

Here's the gist with your Phena-Plus, which blends two antihistamines (chlorpheniramine and pyrilamine) plus the decongestant phenylephrine. Chlorpheniramine in particular has a mild effect on serotonin in the brain. Iboga (through its compound ibogaine) also nudges serotonin levels up. On paper, stacking the two could add together and raise the small chance of serotonin syndrome, which can show up as agitation, sweating, fast heartbeat, shivering, or muscle twitching.

I want to be straight with you: this concern is theoretical, based on how these things work rather than real-world reports. Honestly, the bigger issue is that iboga itself carries serious heart-rhythm risks and is illegal in the U.S. I'd steer clear of it and check with your pharmacist or doctor before combining anything.

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, Pheylephrine, Pyrilamine 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

Let me walk you through this one. Phena-Plus contains chlorpheniramine and pyrilamine, two antihistamines that work partly by blocking acetylcholine, a nervous system messenger. The theory here is that Iboga might raise acetylcholine levels by slowing the enzyme that breaks it down. If that happened, it could push back against the drying, calming effects of those antihistamines, so the product might not work quite as well for your runny nose or sneezing.

Honestly though, this is very theoretical. It comes only from lab dish studies, and the main compound in Iboga, ibogaine, did not even show this effect. On top of that, Iboga itself is illegal and genuinely dangerous to your heart rhythm, so I would steer clear regardless. Please check with your pharmacist or doctor with any questions.

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, Pheylephrine, Pyrilamine 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 key thing to understand: in this pairing, your cold and allergy combo (Phena-Plus, which has chlorpheniramine, phenylephrine, and pyrilamine) is acting as a mild blocker of a liver enzyme called CYP2D6. Iboga's active compound, ibogaine, leans on that same enzyme to be cleared from your body. So the concern isn't really about your allergy medicine getting stronger. It's that ibogaine could pile up, since one small study showed roughly double the exposure when CYP2D6 was blocked.

That matters because Iboga already carries serious risks, including dangerous heart rhythm changes. Honestly, the bigger issue is that Iboga is illegal and unsafe outside research settings, and we don't recommend it at all. Please talk with your pharmacist or doctor before combining anything with it.

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, Pheylephrine, Pyrilamine 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, Pheylephrine, Pyrilamine)
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, Pheylephrine, Pyrilamine

This page covers Iboga only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine, Pheylephrine, Pyrilamine page lists 198 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 · 149 moderate · 43 minor.

From our pharmacist’s overview on the Chlorpheniramine, Pheylephrine, Pyrilamine page

“Reaching for Phena-Plus (chlorpheniramine, phenylephrine, and pyrilamine) usually means a miserable cold or allergy flare, and the same cabinet often holds grapefruit juice or St. John's wort.”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine, Pheylephrine, Pyrilamine interaction page

How much people look this up

Where Iboga and Chlorpheniramine, Pheylephrine, Pyrilamine 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

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

29 days ago today
Medication Chlorpheniramine, Pheylephrine, Pyrilamine
Top 25%

#373 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, Pheylephrine, Pyrilamine, 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, Pheylephrine, Pyrilamine supplement interactions › Every supplement checked against Chlorpheniramine, Pheylephrine, Pyrilamine, 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, Pheylephrine, Pyrilamine Together: Common Questions

Can you take Iboga with Chlorpheniramine, Pheylephrine, Pyrilamine?
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, Pheylephrine, Pyrilamine?
Chlorpheniramine, Pheylephrine, Pyrilamine 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, Pheylephrine, Pyrilamine 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.