Drug & supplement interaction

Iboga + Selpercatinib

Selpercatinib brand name: Retevmo.

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

Iboga has a moderate interaction with Selpercatinib. Theoretically, iboga may have an additive effect with drugs that prolong the QT interval.

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

Iboga and Selpercatinib

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

Moderate

QT INTERVAL-PROLONGING DRUGS

Why this applies to Selpercatinib

Selpercatinib falls under QT INTERVAL-PROLONGING DRUGS — the group Iboga interacts with.

Theoretically, iboga may have an additive effect with drugs that prolong the QT interval.
Numerous case reports suggest that ibogaine, a constituent in iboga, can cause QT interval prolongation.
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 concern with putting Iboga and Selpercatinib (Retevmo) together. Both can stretch out something on your heart's electrical cycle called the QT interval. Selpercatinib is already known to do this on its own, and case reports show that ibogaine (Iboga's active alkaloid) can too. Stacking two QT-prolongers raises the risk of a dangerous, sometimes life-threatening heart rhythm.

This isn't about Iboga changing how your body clears the drug, it's an additive heart effect. The evidence here is mostly anecdotal, so it's not proven, but with a serious cancer medicine like this one I wouldn't take the chance. On top of that, Iboga itself carries real heart and safety risks and is illegal in many places. Please talk with your oncologist or pharmacist before mixing anything with Selpercatinib.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. O'Connell CW, Gerona RR, Friesen MW, Ly BT. Internet-purchased ibogaine toxicity confirmed with serum, urine, and product content levels. Am J Emerg Med. 2015; 33(7):985.e5-6. PubMed
  2. Vlaanderen L, Martial LC, Franssen EJ, van der Voort PH, Oosterwerff E, Somsen GA. Cardiac arrest after ibogaine ingestion. Clin Toxicol (Phila). 2014;52(6):642-3. PubMed
  3. Asua. Growing menace of ibogaine toxicity. Br J Anaesth. 2013;111(6):1029-30. PubMed
  4. Hoelen DW, Spiering W, Valk GD. Long-QT syndrome induced by the antiaddiction drug ibogaine. N Engl J Med. 2009;360(3):308-9. PubMed
  5. Paling FP, Andrews LM, Valk GD, Blom HJ. Life-threatening complications of ibogaine: three case reports. Neth J Med. 2012;70(9):422-4.
  6. Pleskovic A, Gorjup V, Brvar M, Kozelj G. Ibogaine-associated ventricular tachyarrhythmias. Clin Toxicol (Phila). 2012;50(2):157. PubMed
  7. Litjens RP, Brunt TM. How toxic is ibogaine? Clin Toxicol (Phila). 2016;54(4):297-302. PubMed
  8. Grogan J, Gerona R, Snow JW, Kao L. Ibogaine consumption with seizure-like episodes, QTc-prolongation, and captured cardiac dysrhythmias. J Emerg Med 2019;57(4):e99-e104. PubMed
  9. 105383 Knuijver T, Schellekens A, Belgers M, et al. Safety of ibogaine administration in detoxification of opioid dependent individuals: a descriptive open-label observational study. Addiction 2021. PubMed
  10. Steinberg C, Deyell MW. Cardiac arrest after ibogaine intoxication. J Arrhythm 2018;34(4):455-457. 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 Selpercatinib 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. Selpercatinib)
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 Selpercatinib

This page covers Iboga only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Selpercatinib page lists 178 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 132 moderate · 35 minor.

From our pharmacist’s overview on the Selpercatinib page

“People facing a RET-driven lung or thyroid cancer often add supplements for strength, sleep, or immune support, and with selpercatinib (Retevmo) that instinct needs a careful check. Eleven of the 178 ingredients here carry a major rating, and the largest cluster affects how the drug is cleared by the CYP3A4 enzyme: St.”

Reviewed by 2 · Jul 18, 2026

Open the Selpercatinib interaction page

How much people look this up

Where Iboga and Selpercatinib 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 Selpercatinib
Top 10%

#249 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 Selpercatinib

What Is Selpercatinib Used For?

Brand name: Retevmo

Selpercatinib treats cancers driven by changes in the RET gene — either a gene fusion (where RET joins abnormally with another gene) or a RET mutation (a change in the gene itself). Your doctor will confirm one of these changes with an FDA-approved test before prescribing it.

It is approved for adults with RET fusion-positive non-small cell lung cancer; adults and children 2 and older with RET-mutant medullary thyroid cancer or RET fusion-positive thyroid cancer; and adults and children 2 and older with other advanced solid tumors that have a RET gene fusion and have not responded to prior treatment.

See full Selpercatinib 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 Selpercatinib, 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 Selpercatinib supplement interactions › Every supplement checked against Selpercatinib, ranked by severity Selpercatinib 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 Selpercatinib Together: Common Questions

Can you take Iboga with Selpercatinib?
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 Selpercatinib 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 Selpercatinib 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.