Ibogaine treatment outcomes for opioid dependence from a twelve-month follow-up observational study

Opioid dependence produces substantial morbidity and mortality, with high relapse rates and limited success of existing pharmacotherapies and psychosocial interventions. Previous research and anecdotal reports have indicated that the psychoactive indole alkaloid ibogaine can attenuate opioid withdrawal, reduce craving and in some cases lead to cessation of use. However, concerns remain about cardiotoxicity and other risks, and prior studies had not clearly established the durability of treatment effects over extended follow-up. Noller and colleagues designed a prospective observational case series to examine the durability of outcomes after a single ibogaine treatment for opioid dependence. Conducted in New Zealand—where ibogaine can be prescribed legally—the study aimed to measure addiction severity over 12 months, with secondary assessment of depressive symptoms and acute opioid withdrawal, to inform the design of future controlled studies and to take advantage of a legal treatment context that might facilitate honest outcome reporting.

This was a non-interventional, prospective observational study approved by New Zealand's Health and Disabilities Multi-region Ethics Committee. Participants were recruited from clients who independently sought ibogaine treatment from two fee-for-service providers (referred to as Provider 1 and Provider 2). Inclusion criteria required voluntary treatment-seeking adults able to communicate in English, who provided contact details for an affiliate for corroboration and agreed to regular follow-up contact for 12 months; prior ibogaine treatment and treatment for reasons other than opioid dependence were exclusion criteria. The investigator operated in an observational capacity and did not participate in treatment delivery. Treatments used oral ibogaine HCl in 200 mg capsules, with product sources including an imported European synthesis and later Remogen™; 42.9% of participants received Remogen™. Participants stopped opioids 12–33 hours (mean 20.2 hours) before ibogaine and were fasted before dosing. Total dosing ranged 25–55 mg/kg (mean 31.4 mg/kg) delivered as staggered doses over 24–96 hours (mean 57 hours). Providers administered initial "test" doses (200 mg) followed by larger doses and then titrated smaller doses, adjusting by clinical observation and SOWS scores. Concomitant medications during treatment commonly included ondansetron, diazepam and zopiclone. Per local regulation, providers determined medical eligibility and documented medical care. Outcome data were collected in up to 14 interviews: baseline, immediate post-treatment, and monthly contacts for 12 months. The primary outcome was addiction severity measured by the ASI-Lite at baseline and months 1, 3, 6, 9 and 12. Secondary measures included the Beck Depression Inventory-II (BDI-II) at baseline, immediately post-treatment and at 3-month intervals, and the Subjective Opioid Withdrawal Scale (SOWS) pre- and post-treatment. Biological verification comprised two random urine screens during follow-up plus a final screen at month 12 when available. The investigator (GN) conducted most interviews in person at baseline and immediately post-treatment and via phone/Skype thereafter; affiliates were contacted to corroborate participant reports when possible. Study oversight was provided by the third author on behalf of an external research association. Descriptive statistics summarised the sample. Longitudinal changes were tested using Friedman's nonparametric ANOVA across assessment times; significant omnibus tests were followed by Wilcoxon signed-rank comparisons with baseline. Analyses were performed in SPSS v23 with alpha = 0.05. The investigators noted the sample was too small to examine subgroup effects by site.

Recruitment began with 20 individuals expressing interest; three declined participation and one was declined treatment by a provider. Sixteen signed consent and 15 were enrolled; one person died during treatment prior to formal enrolment and one was disqualified after failing to complete treatment as judged by their provider. The reported dataset therefore describes outcomes for 14 participants. Participants were aged 28–47 years (mean 38, s.d. 4.8), 50% were female, and all identified as Caucasian. Baseline depressive symptoms were moderate on average (BDI-II mean 22.1, s.d. 10.8). Participants had a history of prior substance-dependence treatments (mean 4.7, range 0–20), and 71% (n = 10) were receiving methadone maintenance at the time of treatment. In the 30 days preceding baseline participants had used opioids on average 28.8 days. Acute withdrawal, as measured by the SOWS, decreased significantly from baseline to the assessment up to 24 hours post-administration (p = 0.015). Although a further reduction was observed at the later (≥ 42 hours) post-administration SOWS assessment, it did not reach statistical significance, a result the investigators attribute to limited sample size. Of the seven ASI-Lite composite domains, only the Drug composite showed a statistically significant decrease over time (Friedman's p = 0.002). The Drug composite score declined from 0.32 at baseline to 0.06 at 12 months (a reduction in excess of 80%; baseline versus 12 months p = 0.004). By contrast, the ASI-Lite Medical composite increased from 0.00 to 0.34 over 12 months (p < 0.05), which the authors interpret as increased reporting of health problems or medical help-seeking. Depressive symptoms improved markedly over time (Friedman's p < 0.001). Mean BDI-II fell from 22.1 at baseline to 9.3 at 1 month and to 4.4 at 12 months. Urine drug testing was inconsistently obtained. Among participants who provided samples, opioid-positive tests were uncommon: at three months 1/8 observed cases were positive (12.5%), at six months 1/7 (14.3%), and at 12 months 2/8 (25.0%). Self-reported ASI-Lite past-30-day opioid use exceeded the incidence of positive urine tests: 43% reported opioid use at three months (n = 14), 50% at six months (n = 14), and 45% at 12 months (n = 11). Reductions in other drug and alcohol use were reported by 21% of participants at three and six months; at 12 months, among 11 participants remaining, 55% reported reduced other drug use and 36% reduced alcohol use. Per-procedure medications during treatment included ondansetron (10 of Provider 2's 13 subjects), diazepam (several participants, doses reported), and zopiclone in isolated cases. Attrition occurred over follow-up: two participants left the study or were lost to follow-up before 12 months, yielding 11 participants with data at 12 months. The investigators were unable to obtain consistently complete biological verification or complete datasets for some participants.

Noller and colleagues interpret their findings as consistent with earlier reports that single-dose ibogaine can acutely attenuate opioid withdrawal and, in some individuals, sustain reductions or cessation of opioid use over extended follow-up. The authors highlight significant reductions in ASI-Lite Drug composite scores and sustained decreases in depressive symptoms (BDI-II) through 12 months as supporting evidence of durable benefit in this small cohort. They also note that many participants described the treatment as providing insight, including some who did not achieve full abstinence. The discussion situates these results relative to outcomes reported for other detoxification and cessation strategies, observing that while direct comparison is limited by small sample size and study design, the proportion of negative urine screens observed among those tested at 3, 6 and 12 months was higher than reported abstinence rates in some taper-based studies. The authors propose that the observed increase in the ASI Medical composite may reflect increased reporting of physical complaints after methadone cessation or greater healthcare-seeking rather than a direct adverse effect of ibogaine. Safety concerns are emphasised. A treatment-associated death occurred during the study period and was investigated by the Health and Disability Commissioner and in a coronial inquiry; the coroner concluded the death was very likely related to ibogaine ingestion and most probably to a cardiac arrhythmia, though definitive post-mortem cardiac pathology was not identified. The investigators review prior reports of fatalities temporally associated with ibogaine and suggest that preexisting cardiovascular comorbidity, polysubstance use, withdrawal-related seizures and variable preparations of ibogaine have been implicated as risk factors. They also discuss pharmacokinetic issues: ibogaine is metabolised to noribogaine by CYP2D6, and poor CYP2D6 metaboliser status could increase active moiety exposure; noribogaine's reported long half-life may raise plasma levels when multiple doses are given over several days. On this basis the authors suggest prudence such as considering genotyping or dose reduction in hepatic impairment or with CYP2D6 inhibitors. Regarding the New Zealand context, the paper argues that legal prescribing creates structural opportunities to improve safety through open engagement among providers, patients and other health professionals, and by enabling development and adherence to clinical or national standards. At the same time, the authors caution that legal status alone does not prevent lapses in duty of care, noting that the fatality occurred at a clinic run by an experienced medical practitioner who was nevertheless found to have breached duty of care. The investigators acknowledge substantial limitations: a small convenience sample filtered by providers, attrition and incomplete datasets, inconsistent biological verification of drug use, and limited generalisability. They therefore refrain from causal claims beyond what the data support and conclude by calling for more rigorous research to evaluate ibogaine's place among treatment options for opioid dependence, given the modest effectiveness and limitations of existing therapies and the global burden of opioid dependence.