This page summarizes what formal research has documented. It is not everything known about iboga: the Bwiti tradition and decades of clinical experience are knowledge too. Before you read: what science sees, and what it can’t.
Ibogaine’s most important side effect is on the heart. At treatment doses it predictably lengthens the QTc interval, the time the heart takes to recharge after each beat. Most people come through this without a dangerous rhythm, but ibogaine can cause serious, sometimes fatal, heart rhythm problems; that is why everyone has an ECG before treatment. Guidelines and reviews agree that screening and monitoring lower the risk.
What are the side effects of ibogaine?
The common ones are unsteadiness (ataxia), nausea and vomiting, headache, a slower pulse and lower blood pressure. Everyone in the published studies became unsteady, some to the point of needing support to walk. It peaks 2 to 6 hours after the dose and clears within about a day.
Less common are seizures, mostly when alcohol or benzodiazepine withdrawal was not managed or in people with epilepsy, and heart effects that last beyond the first day.
After ibogaine, the body’s tolerance to opioids can be much lower than before. Going back to a dose that used to feel normal can cause a fatal overdose.
Why does ibogaine affect the heart?
Ibogaine, and noribogaine, the long-lasting substance the body makes from it, block a potassium channel called hERG that heart cells use to recover after each beat. Recovery takes longer, and on an electrocardiogram (ECG) this shows as a longer QTc. A long QTc can set off torsades de pointes, a fast, twisting rhythm that can stop the heart from pumping. Ibogaine also slows the pulse, which lengthens the QT further.
A longer QTc is the expected effect of a treatment dose, not a rare reaction. Screening tries to keep that expected change from becoming a dangerous rhythm. Noribogaine stays in the body for days, the likely explanation for heart effects that appear late. More on noribogaine in how ibogaine works in the brain.
How much does the QTc change, and for how long?
In the most detailed human study so far, in a Dutch hospital, a single 10 mg/kg dose lengthened the QTc by about 100 milliseconds (ms) on average. Half of the 14 patients passed 500 ms, the level at which the 2016 clinical guideline calls for transfer to hospital. No one developed torsades de pointes. More than 24 hours after the dose, 6 of the 14 still had a QTc above 450 ms.
The same group found that the QTc reaches its ceiling at levels far below those a full dose produces; the authors estimate the dose would have to be cut more than tenfold to lower the QTc risk in a meaningful way. Case reports, mostly after unsupervised use or very high doses, describe a QTc that stayed long for up to 12 days.
Who is at higher risk?
The risk is higher when something adds to ibogaine’s own effect on the heart. This is the list a medical team works through before treatment:
- Heart. A long QTc (the 2016 guideline excludes values above 450 ms in men and 470 ms in women), congenital long-QT syndrome, structural heart disease, heart failure, a previous heart attack, a resting pulse below 50, significant arrhythmias or fainting.
- Electrolytes. Low potassium or magnesium, and what drives them down: vomiting, diuretics, poor nutrition, heavy drinking.
- Metabolism. A slow CYP2D6, the liver enzyme that breaks ibogaine down.
- Medicines that also lengthen the QT interval, such as methadone, buprenorphine, ondansetron, quetiapine and some antibiotics, antifungals and antihistamines.
- Medicines that block CYP2D6, such as bupropion, fluoxetine and paroxetine.
- Substances and withdrawal. Cocaine; alcohol or benzodiazepine withdrawal; recent fentanyl use.
- Liver and kidneys. Liver disease or significant kidney disease.
- Women. Very few women have been studied, and the guideline’s QTc limits differ for women and men.
This is why the decision is made case by case, with a medical team. If you take any medicine on this list, it may need a taper or a supervised detox first, planned with our medical team. Please don’t stop or cut down anything on your own.
What do the guidelines recommend?
The main guidelines, including the 2016 clinical guidelines and the MAPS Investigator’s Brochure, agree on a common core:
- Before treatment: a 12-lead ECG and a heart history; blood tests for electrolytes, liver and kidney function; a full review of medicines and drugs; and correction of low potassium or magnesium before any dose.
- During treatment: continuous ECG monitoring through the acute phase, staff trained in advanced cardiac life support, a defibrillator and a plan for transfer to hospital.
- Afterwards: observation for days, not hours.
Ibogaine is not an approved treatment, and the research on its heart risk is still small: the true risk per treatment, whether magnesium prevents arrhythmias and the risk in women are not yet known.
What does IbogaQuest do?
Here is what we do; the full detail is on how our medical screening and monitoring work.
We have worked in Tepoztlán, Mexico, since 2009. Most of our protocol happens before anyone is accepted. Two physicians review every case independently, starting with a 12-lead ECG done no more than three months before treatment, read against the 2016 guideline’s QTc limits with Fridericia’s formula; borderline values go to a cardiologist before we decide. Blood tests cover liver and kidney function, potassium, sodium and calcium, and abnormal values are corrected before treatment, never during it. Blood pressure and a urinalysis are part of intake, and a stress test may be required for people over 60 or with specific conditions.
Medicines that block CYP2D6 are tapered with the guest’s own prescriber, and methadone or buprenorphine is switched to a short-acting opioid, well before treatment. Kratom and 7-OH, benzodiazepines, alcohol, fentanyl and some psychiatric medicines may also need a taper or a supervised detox first. We decline people we cannot treat safely outside a hospital.
Our monthly retreat has two doses: the full dose (the flood) on Tuesday, which begins with a test dose, and a booster dose on Friday. If a guest shows a prolonged QTc, a dangerous rhythm, fainting or a slow pulse with symptoms, no more ibogaine is given and the guest is transferred to hospital.
A nurse, a paramedic and two ibogaine providers are on site day and night for the whole retreat, and help guests every time they stand or walk, bathroom trips included. On treatment days an ambulance with paramedics and a monitor-defibrillator is on site as well. The hospital we transfer to, in Cuernavaca, is about 30 minutes away, and guests stay in our care for at least 72 hours after the first dose. Every guest also receives 1 g of magnesium sulfate by IV the day before the session, as one layer among several.
If anything on this page applies to you, or you are not sure, tell us during intake. Talk to our medical team, and when the time is right for you, the application is here.
Frequently asked questions
Should I stop my medicines before treatment?
Some medicines may need a taper or a supervised detox first, planned with our medical team. Please don’t stop or cut down anything on your own.
Related topics
- What the research on ibogaine says
- How ibogaine works in the brain
- How our medical screening and monitoring work
Medically reviewed by Dr. Juan Moller · Last reviewed 10 October 2026
Sources
- Knuijver T, et al. (2022). Addiction. Safety of a 10 mg/kg dose in opioid detox. doi.org/10.1111/add.15448
- Knuijver T, et al. (2024). Journal of Psychopharmacology. Blood levels, CYP2D6 and the QTc. doi.org/10.1177/02698811241237873
- Mestre D, et al. (2024). Cureus. Cardiac arrest after a test dose. doi.org/10.7759/cureus.63487
- Koenig X, Hilber K (2015). Molecules. Review of ibogaine and the heart. doi.org/10.3390/molecules20022208
- Global Ibogaine Therapy Alliance (2016). Clinical Guidelines for Ibogaine-Assisted Detoxification, v1.1. Library card
- MAPS (June 2026). Ibogaine Investigator’s Brochure, v1. Library card
Medical note
Ibogaine is a Schedule I substance in the United States and is not approved by the FDA for any use. This page is educational and does not replace a medical evaluation.