FDA has put on paper what a first U.S. ibogaine trial might look like, and it looks more like a cardiology study than a psychedelic one. In a request for information published in the Federal Register on October 6, the agency described its “preliminary thinking” on an early-phase design: an open-label trial in which small groups each receive a single dose, escalating from group to group, inside an inpatient unit able to manage a life-threatening arrhythmia.
The notice is not guidance. FDA says it “does not establish legally enforceable requirements or regulatory expectations,” that it has “made no final determination,” and that it is describing approaches it is “considering” before “taking any additional action, such as issuing guidance.” Comments are due November 20.
It is still a detailed public account of how the agency is thinking about ibogaine, and it arrives because the government is paying for trials. The design it sketches shows what a sponsor would likely need under that approach: a hospital, a characterized drug, a way to genotype participants, and an answer to a problem FDA itself leaves open. That problem is how to take people with opioid use disorder off methadone or buprenorphine, medications that lower their risk of death, before dosing them.
Why FDA is writing this now
The notice says the Department of Health and Human Services is funding ibogaine development through two channels: an ARPA-H program to collect safety and efficacy data in early-phase trials, and NIDA-funded research on ibogaine for opioid use disorder. The first federally supported trials are expected to enroll adults with opioid use disorder and adults with PTSD.
FDA is direct about the risks. It identifies “serious safety risks” that could expose participants to “an unreasonable and significant risk of illness or injury,” citing the regulation under which it places studies on clinical hold. The three it names are prolongation of the QTc interval, a measure of how long the heart takes to reset between beats, with the associated risk of fatal arrhythmia; neurotoxicity in animal studies; and uncertainty about a safe starting dose in humans.
It is equally direct about the evidence. Published ibogaine studies, the agency writes, mostly lack participant-level data and adequate characterization of the product that was given, including its dose, purity, and potency. The questions an FDA advisory committee raised about ibogaine in 1993 “remain relevant today.”
The design FDA is considering
Every element below is described in the notice as something a trial “could” or “should” include under the approach FDA is considering. None is a requirement.
Dose. Participants could be enrolled in sequential ascending-dose groups, starting at a dose justified by the literature and “not exceeding 10 mg/kg,” with participants in each group dosed one at a time. FDA notes that published reports describe doses from 5 to 20 mg/kg and says those “lack adequate safety margins based on available nonclinical data.” It asks whether 10 mg/kg is the right ceiling.
Setting. The care setting “should be an inpatient unit equipped to manage a life-threatening arrhythmia.” The notice lists what that would likely include: continuous heart rhythm monitoring, a physician-led team trained in advanced cardiac life support, a defibrillator at the bedside, drugs to treat the arrhythmia, emergency cardiac pacing, and ventilator support. A baseline recording, for example over 24 hours, could precede dosing. Continuous monitoring would run until the rhythm is normal and the QTc interval is back near its starting value, which “could be as long as 36 hours.” Participants would stay in the monitored unit for, as an example, at least 36 hours, and discharge could depend on criteria such as a 12-lead ECG at 48 hours showing no QTc prolongation.
Genotype. Because the enzyme CYP2D6 converts ibogaine to its active metabolite, noribogaine, participants “could be genotyped for it, with only fast and intermediate metabolizers included.” People who metabolize the drug slowly would be left out of a first trial.
Heart rhythm thresholds. A baseline QTcF of 430 milliseconds or more is listed as a likely exclusion. Dosing would pause for review if a participant’s QTc stayed above 500 milliseconds for more than two days, or after a sustained ventricular arrhythmia, a seizure, new suicidal thoughts or lasting perceptual disturbances, a possibly related death or serious adverse event, or severe adverse events in two or more participants in a group.
Who could enroll. Adults 18 to 55 “who have stopped taking psychiatric medications,” without structural heart disease, a personal or family history of arrhythmia, a history of seizures, psychosis, or bipolar disorder, or recent suicidal thoughts.
Oversight. A safety review committee with a cardiologist, and an independent data and safety monitoring board with a cardiologist, a neurologist, a psychiatrist, and a biostatistician. Trials in opioid use disorder would add an addiction medicine physician to both. FDA says cognitive testing repeated through 12 months after dosing may help separate short-term effects from lasting ones.
Several of these elements restate existing rules and guidance, including the agency’s July guidance on psychedelic trials. Others, the notice says, “are not derived from existing guidance and are described here for public comment.”
The medication problem FDA leaves open
Before dosing, the notice says, participants “should stop medications that prolong the QTc-interval, slow the heart rate, interact with CYP2D6, or raise serotonin levels.” Its examples include opioid agonist medications, naming methadone and buprenorphine, as well as antipsychotics, antiemetics, and SSRIs.
For the PTSD population the agency describes, people who have not responded to an SSRI and a course of trauma-focused psychotherapy, stopping an SSRI is a more conventional step.
For opioid use disorder it is the central difficulty. The population FDA suggests is people with moderate or severe disorder who have not reached sustained remission “despite adequate treatment with an FDA-approved medication for OUD, including opioid agonist treatment.” Those are patients likely to be on methadone or buprenorphine, the medications the same design would have them stop. FDA does not resolve this. It asks the public what “approaches to discontinuing opioid agonist medications before dosing (including setting, duration, and measures to mitigate risks from loss of opioid tolerance) would best manage associated risks.”
That question carries much of the trial’s ethical weight. A participant who stops agonist treatment to receive a single investigational dose leaves the unit with lower opioid tolerance, whether or not the drug worked. The notice proposes no plan for that period. It asks commenters for one.
Who can run a trial like this
The design is a hospital study. Whoever sponsors one needs an inpatient unit with cardiac monitoring and resuscitation on hand, and specialists to fill the oversight bodies.
One federally funded project already sits in a hospital. NIH’s grant database shows a NIDA cooperative agreement to Brigham and Women’s Hospital, titled “Safety and preliminary efficacy of ibogaine as a treatment for opioid use disorder,” with a first-year award of $2.29 million and a project period from June 15, 2026 to May 31, 2028.
ARPA-H’s program is called ASCENT-IBO, for Accelerating Safe Clinical Evaluation of Novel Treatments: Ibogaine for Better Outcomes in Opioid Use Disorder. It is a solicitation, not yet a set of funded teams: solution summaries are requested by October 15, and no awards are listed. It is limited to opioid use disorder that is treatment-resistant or carries an elevated risk of death. FDA’s notice does not say which program would fund the PTSD trials it mentions, and the NIDA award identified here is also for opioid use disorder.
ARPA-H’s notice does not favor hospitals over companies. It says proposals “led by a commercial entity” responsible for running the trial “may be most advantageous,” and that it will prioritize teams with an IND submitted or about to be. It also asks for combined Phase 1 and 2 trials, with a placebo or active comparator, at doses reaching “psychoactive exposure levels associated with therapeutic efficacy.” FDA is describing an open-label, single-dose escalation study with a 10 mg/kg ceiling. ARPA-H’s notice was posted in August, two months before FDA’s, and neither document says how a proposal written to the first would fit the design in the second.
In Texas, the state health commission selected UTHealth Houston in December 2025 to lead a consortium with UTMB Health, backed by $50 million the legislature had authorized on the condition of matching non-state funds. That contract is not complete. The commission’s program page says recent plans submitted to it do not meet the statute’s requirements, including those on matching funds and on revenue from intellectual property. On March 31, the lieutenant governor and the House speaker said drug company proposals had not met the law’s standards and that the state intends to fully fund the research itself.
One company has a related foothold. FDA’s notice says it has allowed an early-phase study of noribogaine hydrochloride to proceed under an IND for alcohol use disorder. It does not name the sponsor. DemeRx announced in April that FDA had accepted its IND for oral noribogaine in that indication, and NIH records show an NIAAA small-business grant to DemeRx for that program. A study of the metabolite, in a different condition, is not an ibogaine study, and it says nothing about whether FDA would accept the design described here. It does mean the agency has already reviewed one sponsor’s IND for a compound in this chemical family.
Companies building supply ahead of a trial have the drug side and not yet the clinical side. Psyence BioMed’s Texas subsidiary has signed a manufacturer. It says it has filed no trial application, and its announcements name no clinical site. Under the design FDA is considering, a sponsor in that position would also need an inpatient cardiac unit and the oversight bodies the notice lists, which in practice points to a hospital or academic medical center as a partner.
No interventional ibogaine trial dosing participants in the United States appears on ClinicalTrials.gov as of October 7. The one U.S. interventional registration that includes ibogaine was withdrawn, and the other U.S. studies listed are observational. That describes the public registry, not INDs, which are not public. ARPA-H’s notice says there are no active trials with an open IND studying ibogaine in opioid use disorder.
Shared data, and a supply question the notice leaves alone
FDA writes that data from the federally funded programs “will be made available publicly to investigators and sponsors” and “may support future later-stage studies.” If that holds, the early safety and pharmacokinetic work, the part FDA says the literature lacks, becomes a shared base. A later sponsor would not have to generate it alone, and would not have it to itself.
Supply is outside the notice. FDA says the ibogaine used “must be well characterized,” with a certificate of analysis and full manufacturing information, and it places the drug’s scheduling outside the scope of comment. Scheduling and manufacturing quotas belong to the DEA. The DEA’s 2026 aggregate production quota for ibogaine, the cap on how much may be manufactured in the United States this year, is 210 grams. As arithmetic only: at 10 mg/kg, an 80-kilogram adult would receive 0.8 grams, so the whole quota is equivalent to roughly 260 such doses. Not all of it is available for trials, and some would go to testing. ARPA-H’s program FAQ says ibogaine for its trials does not need to come from a U.S. source, and that the agency “cannot at this time make any certain commitments” about waivers from FDA or the DEA. No proposed 2027 quota had been published as of October 7, and nothing in the records reviewed links the trial design to a quota increase.
The notice should be read for what it is. It describes “one possible approach,” FDA says it will evaluate each IND individually, and the elements may change after comments close on November 20. What it already shows is the shape of the agency’s concern: it is approaching a first ibogaine trial as a cardiac safety study in a vulnerable population. That makes the hospital the scarce input. A sponsor with funding or drug supply and no inpatient cardiac unit is not yet in a position to run the trial FDA describes.