Tabernanthe iboga

# Research Output: Tabernanthe iboga

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## Botanical Identity

**Accepted binomial:** *Tabernanthe iboga* Baill.
**Family:** Apocynaceae (subfamily Rauvolfioideae)
**First publication:** Baillon, H. (1888). *Bulletin Mensuel de la Société Linnéenne de Paris* 1: 783 [Ref 43].
**Common names:** iboga, eboka, ibogha (Bwiti tradition), ebogha

**Synonyms (7 total, from POWO) [Ref 43]:**
- *Iboga vateriana* Braun-Blanq. & K.Schum.
- *Tabernanthe albiflora* Stapf
- *Tabernanthe bocca* Stapf
- *Tabernanthe mannii* Stapf
- *Tabernanthe pubescens* Pichon
- *Tabernanthe subsessilis* Stapf
- *Tabernanthe tenuiflora* Stapf

**Native range [Ref 43]:** West and Central Tropical Africa to Angola. Specifically: Cameroon, Central African Republic, Republic of Congo, Democratic Republic of Congo, Gabon, Angola, and Cabinda. Gabon is the primary source of commercially traded iboga material.

**Habitat:** Shrub or tree growing in wet tropical biome, typically forest understory; also found in riverine or swamp forest and relatively wet savannah; elevation 0–1,500 m above sea level [Ref 43].

**Cultivation status:** Primarily wild-harvested. Cultivation exists (Gabon permits cultivation on private land with Ministry permits) but wild harvesting predominates in the commercial supply. The IUCN Red List classifies *T. iboga* as Least Concern based on wide distribution, but overcollection for global ibogaine demand has depleted wild populations, particularly in Gabon [Ref 54]. In 2000, Gabon declared iboga a "national cultural heritage strategic reserve" and enacted an export ban on wild-harvested iboga in 2019 [Ref 54].

**Morphology:** Perennial shrub or small tree, 1.5–2 m tall (occasionally taller under forest canopy). Leaves are shiny, ovate-oblong, in whorls. Flowers small, white to light pink. Fruits are orange-yellow, ovoid, edible. The root and root bark contain the highest alkaloid concentrations; the alkaloid content decreases from root to stem bark, then leaves.

**Misidentification risk:** *Tabernanthe iboga* is the source plant for traditional Bwiti use and most commercial ibogaine extraction. *Voacanga africana* (also Apocynaceae) contains voacangine (a chemical precursor to ibogaine), and is a commercially available semi-synthetic ibogaine source. *Tabernaemontana* species (a closely related genus) contain iboga-type alkaloids including ibogaine and voacangine but at different ratios than *T. iboga* [Ref 5 — González-Trujano 2023, Ref 40 — Lopez-Vazquez 2026]. Misidentification of products sold as "iboga" as *Voacanga africana* or *Tabernaemontana* spp. has occurred [Ref 31].

**Discrepancies with brief seed data:** The brief contained no botanical seed data. All botanical data above is newly established through primary research. Family (Apocynaceae), genus/species, native range, and synonyms are now confirmed against POWO [Ref 43].

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## Alkaloid / Cannabinoid Profile

### Primary Constituents

**1. Ibogaine** — the major psychoactive alkaloid. *T. iboga* root bark characteristically contains ibogaine as the most abundant psychoactive constituent.
- **PubChem CID:** 197060
- **Molecular formula:** C₂₀H₂₆N₂O; **MW:** 310.4 g/mol
- **Structure:** Pentacyclic monoterpene indole alkaloid (ibogane skeleton); 12-methoxyibogamine; an indolethylamine embedded in a cage-like pentacyclic framework
- **InChIKey:** HSIBGVUMFOSJPD-CFDPKNGZSA-N

**2. Noribogaine (12-hydroxyibogamine)** — the primary pharmacologically active metabolite of ibogaine, formed in vivo by CYP2D6-mediated O-demethylation.
- **PubChem CID:** 3083548
- **Molecular formula:** C₁₉H₂₄N₂O; **MW:** 296.4 g/mol
- **InChIKey:** RAUCDOKTMDOIPF-RYRUWHOVSA-N
- Noribogaine has a longer half-life (~28–48h) than ibogaine, persistent serotonin reuptake inhibition, and kappa opioid agonism

**3. Tabernanthine** — structural isomer of ibogaine; differs in methoxy group position (C-6 vs C-7)
- **PubChem CID:** 6326116
- **Molecular formula:** C₂₀H₂₆N₂O; **MW:** 310.4 g/mol

**4. Ibogamine** — desmethoxy analog lacking the methoxy group
- **PubChem CID:** 100217
- **Molecular formula:** C₁₉H₂₄N₂; **MW:** 280.4 g/mol

**5. Voacangine** — also present in *T. iboga* root bark; a coronaridine carboxymethyl ester; used as a semi-synthetic ibogaine precursor; demonstrates hERG blockade IC₅₀ ~2.25 μM [Ref 16]

**6. Coronaridine** — biosynthetic precursor to ibogaine in the indole alkaloid pathway; CYP71 enzyme family catalyzes C19-hydroxylation of coronaridine [Ref 40]

**7. Ibogaline** (6-methoxytabernanthine) — minor alkaloid

### Quantified Concentrations

Bouso et al. (2020 [Ref 31]) conducted GC/MS analysis of 16 commercial iboga-derived products from treatment providers and online vendors. Findings:

| Product form | Ibogaine content |
|---|---|
| Root bark | 0.6–11.2% |
| Total Alkaloids (TA) | 8.2–32.9% |
| Purified Total Alkaloids HCl (PTA HCl) | 73.7% (single sample) |
| Ibogaine HCl | 61.5–73.4% |
| One sample (labeled as iboga) | No iboga alkaloids detected |

Additional alkaloids and unknown substances were found in almost all samples, including coronaridine, voacangine, ibogamine, tabernanthine, and ibogaline [Ref 31].

The 1958 foundational chemistry paper by Bartlett, Dickel, and Taylor [Ref 51] established the chemical structures of ibogamine, ibogaine, tabernanthine, and voacangine — the foundational structural pharmacognosy of the genus.

### Alkaloid Variability
Ibogaine content in root bark (0.6–11.2%) shows extreme variability that is likely related to geographic origin, plant age, plant part (root bark vs. stem bark vs. leaves), season, and post-harvest handling. This variability creates substantial overdose risk when dosing from uncharacterized root bark preparations [Ref 31].

### How Preparation Alters Constituent Ratios
- **Raw root bark:** Full alkaloid profile including non-ibogaine alkaloids (voacangine, coronaridine, tabernanthine, ibogamine). Highly variable ibogaine content. Traditional Bwiti use involves chewing raw root bark.
- **Total Alkaloid (TA) extract:** Concentrates all alkaloids; still contains full spectrum but at higher relative concentrations.
- **Purified Total Alkaloids / Ibogaine HCl:** Near-pure ibogaine; removes most co-alkaloids. Used in clinical research. This eliminates voacangine-related hERG contribution beyond ibogaine itself.
- **Aqueous decoctions:** Not commonly used for *T. iboga* (unlike *Mitragyna speciosa* or ayahuasca preparations); root bark is typically chewed or taken as powder.

### Minor Alkaloids
Tabernanthe species also contain small amounts of ibogaline (6-methoxytabernanthine) and related ibogane-skeleton compounds. Their in vivo contributions are not well-characterized at typical use concentrations. Literature on minor alkaloid effects is largely limited to in vitro receptor binding data.

### Biosynthesis Note
The biosynthetic pathway from strictosidine (shared with all monoterpene indole alkaloids) to iboga alkaloids has been substantially elucidated. CYP71 family enzymes (VCOH1-3) catalyze C19-hydroxylation of coronaridine and voacangine in related *Voacanga thouarsii* [Ref 40], indicating convergent enzyme solutions for iboga alkaloid production across Apocynaceae genera.

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## History & Ethnobotany

### First Scientific Description
The species was formally described by Henri Ernest Baillon in 1888 [Ref 43]. The genus *Tabernanthe* was established by Baillon to accommodate this plant and related taxa within the family Apocynaceae.

### Traditional/Indigenous Use
*Tabernanthe iboga* is the sacramental plant of the **Bwiti religion**, practiced primarily by the Mitsogho and Fang peoples of Gabon and neighboring countries, with significant Babongo (hunter-gatherer) participation [Ref 32]. The Bwiti religion integrates ancestral veneration, initiation, and healing into a complex ceremonial structure in which iboga root bark is central.

Iboga is consumed in two primary traditional contexts [Ref 19, Ref 32]:
1. **Large initiation doses ("grand iboga"):** Eaten over 1–3 days in quantities described as several hundred grams of root bark, producing intense and prolonged visionary states lasting 24–48+ hours. These initiation rites are conducted for young adults entering the Bwiti tradition and are considered a symbolic death-and-rebirth experience enabling contact with ancestral spirits.
2. **Smaller ceremonial doses:** Taken in ceremonial settings for healing, guidance, or community ritual, without reaching the full visionary threshold.

The Babongo of southern Gabon have documented use of iboga in hunting and ceremonial contexts, with social and land-use patterns changing significantly since the 1960s [OpenAlex — Matsuura 2011].

Traditional medicinal uses at sub-visionary doses include: stimulant to combat fatigue and hunger during extended hunting; aphrodisiac; treatment of fever, pain, and parasitic infection [Ref 19, Ref 43 via POWO context].

**⚠ Flag for human review:** Traditional-use accounts are the primary evidence for ceremonial dose ranges, preparation methods, and phenomenological descriptions. No controlled ethnopharmacological studies with quantified dosing have been conducted in the traditional Bwiti setting.

### Western Discovery and Early Research
French colonial botanists and pharmacologists encountered iboga in the late 19th century. The first alkaloid isolation from *T. iboga* root bark — yielding what would eventually be named ibogaine — is attributed to **Landrin** (1898) and more fully to **Dybowsky and Landrin** (1901), working in the French colonial pharmacological tradition (cited in Alper 2001 review [Ref 28 context]; not independently verified via API). The plant itself had been documented in European herbaria from the 1850s–1880s exploratory period.

### 20th Century Pharmaceutical Interest
- **1930s–1950s:** Ibogaine was sold in France as a neuromuscular tonic under the brand name "Lambarene" (5 mg tablets); used as a fatigue remedy and mild stimulant [cited in Alper 2001; unverified via API].
- **1957:** Leo Zeff reportedly experienced ibogaine (unconfirmed in primary sources via API searches).
- **1962:** **Howard Lotsof**, a 19-year-old heroin-dependent American, self-administered ibogaine and reported that his opioid craving and withdrawal had ceased. He subsequently observed similar effects in multiple acquaintances [Ref 8].
- **1985–1986:** Lotsof obtained US patents for ibogaine treatment of multiple substance dependencies.
- **1967:** US DEA classified ibogaine as Schedule I under the Controlled Substances Act.
- **1990s:** NIDA initiated preclinical studies; Mash et al. began Phase I clinical trials at a St. Kitts clinic outside US jurisdiction [Ref 50, Ref 14].
- **2000:** Gabon declared iboga a "national cultural heritage strategic reserve" [Ref 54].
- **2019:** Gabon banned export of wild-harvested iboga [Ref 54].
- **2024:** Landmark MISTIC trial published in *Nature Medicine* for ibogaine in TBI/PTSD [Ref 28].
- **2026:** US executive order to accelerate ibogaine research and regulatory review [Ref 46].

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## Neuroscience & Mechanism

### Primary Receptor Targets (Ibogaine)
Ibogaine exhibits exceptionally broad, multi-target ("matrix pharmacology") pharmacology [Ref 2]:

| Target | Action | Evidence level |
|---|---|---|
| VMAT2 (vesicular monoamine transporter 2) | Inhibitor; submicromolar IC₅₀ | In vitro, mouse brain [Ref 2] |
| SERT (serotonin transporter) | Inhibitor; transport inhibition in brain slices | In vitro/ex vivo [Ref 2] |
| OCT2 (organic cation transporter 2) | Inhibitor | In vitro [Ref 2] |
| α3β4 nicotinic acetylcholine receptor | Antagonist | In vitro [Ref 9] |
| NMDA receptor (PCP/channel site) | Antagonist; Ki(H) 0.01–0.05 μM cortex | Radioligand binding [Ref 27] |
| Kappa opioid receptor | Agonist | Animal models [Ref 26] |
| Sigma-1 and sigma-2 receptors | Binding; Ki 1.5–3 μM | Radioligand binding [Ref 27] |
| Mu-opioid receptor | Biased partial agonist (low beta-arrestin recruitment) | In vitro [Ref 39] |
| 5-HT₂A receptor | Indirect effects; mediates some behavioral responses | 5-HT₂A KO mouse model [Ref 5] |
| GDNF pathway (VTA) | Upregulation; Ret receptor phosphorylation | Rodent in vivo [Ref 11] |

### Noribogaine-Specific Pharmacology
Noribogaine (the primary CYP2D6 metabolite) demonstrates:
- Submicromolar VMAT2 inhibition and partial serotonin release from synaptic vesicles [Ref 2]
- SERT inhibition in brain slice and rat synaptosome preparations [Ref 2]
- Kappa opioid receptor agonism contributing to anti-addictive effects [Ref 26]
- 5-HT₂A receptor-mediated sex-dependent effects on NMDA transmission in mPFC [Ref 5]
- Longer half-life than ibogaine (~28–48h vs ~7–10h); explains persistent effects and delayed cardiac risk

### CNS Mechanism Summary
Ibogaine's anti-addictive effects involve multiple converging mechanisms [Ref 26, Ref 36]:
1. **Acute dopamine suppression:** Ibogaine and noribogaine decrease extracellular dopamine in nucleus accumbens, acutely reducing drug reward reinforcement.
2. **GDNF upregulation in VTA:** Microinjection into VTA reduces ethanol self-administration, mimicked by exogenous GDNF [Ref 11].
3. **NMDA antagonism:** Attenuates opioid/stimulant withdrawal through glutamatergic normalization [Ref 26, Ref 27].
4. **Kappa opioid effects:** Contributes to effects on opioid and stimulant self-administration [Ref 26].
5. **VMAT2/SERT inhibition ("SynRI"):** Dual vesicular and plasma membrane serotonin transport modulation [Ref 2].
6. **Neuroplasticity/GDNF:** Structural brain changes observed in humans at 1 month post-treatment (increased cortical thickness, subcortical volume, decreased brain age) [Ref 33].
7. **Remyelination:** Proposed mechanism involving NMDA, kappa, and sigma receptor actions reducing excitotoxicity and promoting neuronal repair [Ref 36].

### Pharmacokinetics

**Ibogaine (oral administration):**
- Rapidly absorbed; Tmax ~1.5–4 h [Ref 15, Ref 20]
- Bioavailability: first-pass metabolism via CYP2D6 substantially converts ibogaine to noribogaine
- Elimination half-life: ~7–10 h in CYP2D6 normal metabolizers; significantly longer in poor metabolizers [Ref 15]
- Distribution: lipophilic; significant adipose sequestration with slow release (explains prolonged duration)
- **CYP2D6 is the primary metabolic enzyme:** O-demethylation to noribogaine. CYP2D6 poor metabolizers have 2× higher active moiety (ibogaine + noribogaine) exposure [Ref 15]
- Paroxetine (CYP2D6 inhibitor) pretreatment → ibogaine AUC substantially elevated; robust correlation (r = 0.82) between CYP2D6 phenotype and ibogaine AUC [Ref 15]

**Noribogaine (metabolite):**
- Formed primarily by CYP2D6; secondary pathway via CYP3A4
- Tmax ~3–4 h post-ibogaine administration [Ref 15]
- Half-life ~28–48 h — substantially longer than ibogaine
- Active pharmacologically (SERT inhibition, kappa opioid agonism, hERG blockade)
- Persistent noribogaine explains QTc prolongation observed 24–72h post-ibogaine administration [Ref 16, Ref 18]

**Glue et al. 2015 [Ref 15]** controlled human PK study (20 mg ibogaine, N=21):
- Normal metabolizers: rapid ibogaine-to-noribogaine conversion; noribogaine peak at median Tmax 4h
- Paroxetine-pretreated (CYP2D6 inhibition): ibogaine detectable to 72h, elimination half-life 10.2h
- 20 mg dose was safe and well-tolerated at this low exploratory dose

**Knuijver et al. 2024 [Ref 20]** PK/PD in OUD patients (10 mg/kg ibogaine HCl):
- Documented relationships between ibogaine/noribogaine PK and side effect magnitude and opioid withdrawal relief

---

## Effects & Dose by Preparation

**⚠ Note:** Published quantitative dose-response data for different preparation types is sparse. The data below combines clinical study doses, traditional use accounts, and pharmacological characterization. Dose values not verified against a Curiosity v1 DB record are flagged.

### Preparation 1: Ibogaine HCl (oral, therapeutic/clinical)

**Dose range:**
- Low exploratory dose (PK studies): 20 mg total (~0.2–0.3 mg/kg); no psychoactive effects [Ref 15]
- Anti-addictive / therapeutic range: **10–20 mg/kg** ibogaine HCl oral [Ref 21 — Knuijver 10 mg/kg; Ref 30 — Mash 2018 variable dosing in N=191]
- Higher doses reported in some addiction treatment settings: up to 25 mg/kg

**⚠ FLAG:** The 10–20 mg/kg dose range is derived from clinical study protocols (Knuijver 2022 used 10 mg/kg; Mash 2018 used variable doses for opioid withdrawal). No standardized dose-response data from controlled RCTs exist for therapeutic endpoint doses.

**Onset:** 1–3 h (oral, ibogaine HCl)
**Peak effects:** 3–8 h
**Duration total:** 12–24 h for acute phase; residual effects (insomnia, heightened senses) may persist 24–48 h

**Subjective effects (from González Espejito et al. 2025 [Ref 3], N=499):**

The Ibogaine Experience Scale (IES) identified 7 empirically-derived factors explaining 53.9% of variance:
1. **Narrative and symbolic visions** — story-like visual sequences, often autobiographical
2. **Visual changes** — altered visual perception, geometry, brightness, color
3. **Discomfort and challenge** — anxiety, fear, nausea, difficult material
4. **Cosmic/Archetypal Visions** — transpersonal content, entity contact, universal symbols
5. **Introspection and personal transformation** — insight, self-review, changed perspective
6. **Somatosensory hypersensitivity and physiological activation** — heightened tactile/auditory sensitivity, nausea, tremor
7. **Dissociation** — detachment from body and ordinary self-sense

**From Brown et al. 2019 [Ref 22] (N=44, States of Consciousness Questionnaire):**
- Mean SCQ scores in many domains exceeded 0.6 (threshold for "complete mystical experience")
- 43% achieved complete mystical experience in >5 of 7 domains
- Qualitative themes: cyclic visions, confronting autobiographical memories, guilt/release, spiritual transformation

**From Olash et al. 2026 [Ref 35] (N=30 veterans, qualitative post-session narratives):**
Four experiential domains:
1. Dialogic trauma re-appraisal (guided autobiographical memory replay)
2. Altered-self and mystical connectedness
3. Emotional resolution (forgiveness, love, renewed purpose)
4. Embodied healing (sensation of neural repair, cognitive clarity)

### Preparation 2: Root bark / Total alkaloid extract (oral, traditional/underground use)

**Dose range:** Highly variable; ibogaine content 0.6–11.2% in root bark [Ref 31], making milligram-equivalent dosing extremely unreliable.

**Traditional Bwiti initiation:** Several hundred grams of root bark reportedly consumed over 1–3 days in grand initiation ceremonies — but quantified alkaloid intake data from traditional ceremonies is absent from published literature.

**⚠ FLAG:** No published dose-response data with verified alkaloid content characterizes traditional or informal root bark use. Dose values from traditional use reports cannot be converted to ibogaine milligram equivalents without product analysis. This is a safety-critical gap.

**⚠ FLAG:** Commercial root bark and total alkaloid products show extreme concentration variability, including one sample with no detectable iboga alkaloids (Bouso et al. 2020 [Ref 31]). Adulteration and mislabeling represent serious overdose and under-dose risks.

### Preparation 3: Magnesium-ibogaine (MISTIC protocol)

Co-administration with magnesium has been investigated as a cardiac risk mitigation strategy [Ref 28].

**Setting:** Stanford MISTIC study (NCT04313712): 30 male special operations veterans with TBI.
- Complementary treatment modalities alongside magnesium-ibogaine protocol
- Specific doses not reported in the published paper [Ref 28]
- Significant improvements in WHO Disability Assessment (Cohen's d = 2.20 at 1 month), PTSD (d = 2.54), depression (d = 2.80), anxiety (d = 2.13)
- Cortical thickness increases in 11 brain regions; subcortical expansion in 8 regions; -1.3 year brain age at 1 month [Ref 33]
- No unexpected or serious adverse events reported [Ref 28]

### Effect Modifiers
- **CYP2D6 genotype:** Poor metabolizers have 2× active moiety exposure; higher cardiovascular risk [Ref 15, Ref 18]
- **Co-administered medications:** CYP2D6 inhibitors (SSRIs: paroxetine, fluoxetine) substantially increase ibogaine exposure [Ref 15]
- **Prior opioid maintenance:** Tapering from methadone/buprenorphine before ibogaine is dangerous if incompletely managed [Ref 37]
- **Set and setting:** Structured psychotherapeutic context appears to enhance therapeutic outcomes (Rocha et al. 2023 systematic review [Ref 7])

---

## Safety & Toxicity

### Acute Toxicity
**Rat LD50:** Not precisely established via API-verified sources. Animal toxicology studies in rats used single doses of 25–100 mg/kg (i.p.); 100 mg/kg caused consistent Purkinje cell degeneration; 25 mg/kg was the NOAEL [Ref 23]. No published mammalian LD50 for ibogaine was retrieved via structured database search.

**⚠ FLAG:** Human LD50 data do not exist. Rat cerebellar toxicity doses (75–100 mg/kg i.p.) likely exceed human therapeutic ranges, but the translation is uncertain given species differences and route of administration.

### Cardiac Toxicity (Primary Human Safety Concern)
Ibogaine and noribogaine block the hERG potassium channel (IKr), which is critical for cardiac repolarization [Ref 16].

**IC₅₀ values for hERG blockade (Alper et al. 2016 [Ref 16]):**
- Ibogaine (from *T. iboga* extraction): IC₅₀ = 3.53 μM
- Ibogaine (from voacangine semi-synthesis): IC₅₀ = 4.09 μM
- Noribogaine: IC₅₀ = 2.86 μM
- Voacangine: IC₅₀ = 2.25 μM
- 18-methoxycoronaridine (18-MC, experimental safer analog): IC₅₀ > 50 μM

**Clinical QT prolongation data (Knuijver et al. 2022 [Ref 21], N=14, 10 mg/kg ibogaine HCl):**
- Mean maximum QTc prolongation: 95 ms (range 29–146 ms)
- 50% of subjects reached QTc > 500 ms during observation
- In 6 of 14 subjects, QTc remained > 450 ms beyond 24 h post-administration
- No torsades de pointes (TdP) observed in this monitored clinical setting
- Severe transient ataxia (inability to walk without support) in **all** patients
- 11 of 14 did not return to morphine within 24 h (primary outcome)

**Fatal arrhythmias:** Reported deaths are attributed to TdP progressing to ventricular fibrillation [Ref 13, Ref 18]. The 10-year UK NPIS case series (Edwards et al. 2025 [Ref 4]) documents real-world ibogaine toxicity cases. Deaths primarily occur in unsupervised settings. Brunt (2026 [Ref 18]) notes cases occurring with therapeutic doses in individuals without pre-existing cardiac conditions.

**Timing of cardiac risk:** Noribogaine's prolonged half-life (~28–48h) means cardiac risk extends beyond the visionary phase — sudden death has been reported up to 72h after ibogaine ingestion [Ref 13, Ref 16].

### Neurological Toxicity
**In rodents:** Ibogaine causes indirect (trans-synaptic) excitotoxic degeneration of Purkinje cells in cerebellar vermis via olivocerebellar projection activation [Ref 12, Ref 25]. Established at 75–100 mg/kg (i.p.) in rats; NOAEL at 25 mg/kg [Ref 23].

Critically, at **40 mg/kg** (within or near the anti-addictive dose range in rodents), ibogaine did NOT cause Purkinje cell degeneration (Molinari et al. 1996 [Ref 24]). This dose-response separation suggests the anti-addictive and neurotoxic properties may be dissociable.

**In humans at therapeutic doses:** Severe transient ataxia is observed in clinical settings [Ref 21]. Long-term Purkinje cell effects in humans at therapeutic doses have not been established in published literature. The MISTIC study showed structural brain improvements, not deterioration [Ref 33].

### Psychological Risks
- Challenging / dysphoric experiences ("bad trips") are common and are captured as one of the 7 IES factors ("Discomfort and challenge") [Ref 3]
- Risk of acute psychological decompensation in individuals with pre-existing psychotic disorders (contraindication)
- Delirium-like states at high doses
- Hyperekplexia (exaggerated startle response) during residual phase

### Herb–Drug Interactions

**⚠ Note on evidence levels:** Mechanism-based CYP interactions are well-established pharmacokinetically; pharmacodynamic interactions are based on mechanism rather than clinical case reports.

| Interactant | Interaction | Evidence basis |
|---|---|---|
| CYP2D6 inhibitors (paroxetine, fluoxetine, bupropion) | ↑ Ibogaine AUC up to 2×; ↑ cardiac risk | Controlled human PK study [Ref 15] — **clinical case report basis confirmed** |
| QT-prolonging agents (methadone, TCAs, antipsychotics, SSRIs, antihistamines) | Additive QT prolongation → TdP risk | Pharmacodynamic mechanism [Ref 13, Ref 18] — **mechanism-based; clinical case reports not individually retrieved** |
| Opioids (acute coadministration) | Pharmacodynamic interaction; ibogaine may precipitate opioid withdrawal OR attenuate withdrawal depending on timing | Animal models [Ref 26]; clinical observations [Ref 30] |
| MOUD (methadone, buprenorphine) — withdrawal for ibogaine | Risk of precipitated severe withdrawal + post-ibogaine opioid overdose risk | Clinical editorial [Ref 37] — **mechanism-based; no controlled clinical trial data** |
| Serotonergic agents (MAOIs, serotonin releasers) | Potential serotonin syndrome via SERT inhibition | Mechanism-based — **no specific clinical case reports retrieved** |

**⚠ FLAG:** Herb–drug interaction severities above classified as mechanism-based are not individually backed by specific case reports retrieved through this research. Clinical supervision and medication review before ibogaine administration is essential.

### Tolerance and Dependence
- **Tolerance:** Not characterized by standard pharmacological tolerance. Ibogaine is typically administered as a single dose in therapeutic contexts. No published evidence of dose escalation or classic tolerance development in humans [Ref 48, Ref 26].
- **Dependence/withdrawal:** Ibogaine does not appear to produce physical dependence. No documented withdrawal syndrome in humans from ibogaine itself. The plant's traditional ceremonial use is intermittent, not daily.
- **Abuse liability:** Not considered a substance of abuse. Animal self-administration models do not show ibogaine self-administration; no compulsive-redosing patterns documented [Ref 47].

### Contaminant/Adulterant Risk
Based on Bouso et al. 2020 [Ref 31] analysis of 16 commercial products:
- One sample labeled as "iboga" contained no iboga alkaloids — **extreme adulteration risk**
- Unknown substances detected in almost all samples
- Wide ibogaine content variability (0.6–11.2% root bark) makes dose titration impossible from uncharacterized material
- No specific heavy metal, pesticide, or mycotoxin data retrieved for iboga products via API searches

**⚠ FLAG:** Heavy metal contamination, pesticide residues, and mycotoxin data for commercially sold iboga products are absent from the published literature retrieved. This parallels concerns for other botanicals and should be flagged as a safety gap.

### Contraindications and Vulnerable Populations
Based on safety literature [Ref 1, Ref 7, Ref 18, Ref 21]:
- **Cardiac disease:** Pre-existing QT prolongation, arrhythmias, heart failure — absolute contraindication
- **CYP2D6 poor metabolizer genotype:** Major risk factor; CYP2D6 genotyping recommended before treatment [Ref 15, Ref 18]
- **Concurrent QT-prolonging medications:** Must be discontinued with appropriate washout
- **Severe hepatic impairment:** CYP enzyme-mediated metabolism; impaired clearance
- **Personal or family history of psychiatric psychosis/schizophrenia:** Risk of precipitated psychosis
- **Pregnancy:** No published safety data; contraindicated by default
- **Opioid maintenance without tapering:** Dangerous discontinuation scenario [Ref 37]
- **Pediatric populations:** No safety or efficacy data

---

## Harm Reduction

### Published Risk Reduction Strategies (from systematic reviews [Ref 7, Ref 1]):
1. **Cardiac screening:** Pre-treatment ECG mandatory; QTc > 450 ms is a standard exclusion criterion
2. **CYP2D6 genotyping:** Recommended before any therapeutic ibogaine administration to identify poor metabolizers requiring dose reduction [Ref 15, Ref 18]
3. **Medication review and washout:** All QT-prolonging and CYP2D6-inhibiting medications must be reviewed and appropriately discontinued
4. **Cardiac monitoring:** Continuous ECG monitoring during and for minimum 24h after administration; defibrillator immediately available [Ref 7, Ref 21]
5. **Electrolyte management:** Hypokalemia and hypomagnesemia potentiate QT prolongation; pre-correction essential
6. **Magnesium co-administration:** MISTIC protocol used magnesium to potentially mitigate cardiac risk [Ref 28]
7. **Supervised setting only:** Medically supervised inpatient setting strongly recommended; death risk in unsupervised settings [Ref 7]
8. **Fall/ataxia prevention:** Severe ataxia occurs in nearly all patients [Ref 21]; immobilization or intensive physical support during experience
9. **Avoid in isolation:** NPIS case series emphasizes importance of trained supervision [Ref 4]

### Testing and Identification
- GC/MS or HPLC analysis of any iboga product before clinical use to determine actual alkaloid content [Ref 31]
- Standard immunoassay drug panels do NOT detect ibogaine [Ref 41]; dedicated LC-MS assay required for plasma/urine detection
- Drug checking services (harm reduction labs) can test root bark and extract products [Ref 31]

### Cessation and Recovery Resources
- No published ibogaine-specific addiction or dependence cessation literature (ibogaine itself is not typically dependence-forming)
- For individuals who experience adverse reactions: emergency cardiac intervention (defibrillation, magnesium sulfate IV for TdP), ICU-level monitoring
- MAPS and ICEERS have published harm reduction guidelines (referenced in Rocha et al. 2023 [Ref 7])

---

## Legal Status

### United States — Federal
**Schedule I** under the Controlled Substances Act since **1967**. No FDA approval. No accepted medical use recognized at federal level. Ibogaine HCl is also Schedule I [Ref 44, Ref 46].

### United States — State Level (as of May 2026 [Ref 44])
**Enacted bills (9 states):**
- **Texas** — SB 2308 (June 2025): $50 million allocated for ibogaine clinical research
- **Arizona** — HB 2871 (June 2025): $5M for Phase I clinical trials
- **Kentucky** — SB 77 (April 2026): $21M annually for SUD research
- **Louisiana** — SB 43 (May 2026): psychedelic-assisted therapy program (effective August 2026)
- **Mississippi** — HB 314 (March 2026): $5M for FDA approval consortium
- **Oklahoma** — HB 3834 (May 2026): clinical trial drug development framework
- **Indiana, California, Tennessee** — various research facilitation bills
- **Oregon** — HB 4110 (first US state to establish regulated ibogaine program)

**Active bills (9 states):** Colorado, Maryland, Massachusetts, Missouri, New Hampshire, New York, Vermont, West Virginia, and others

### United States — Recent Federal Developments
- **2026 US Executive Order:** Directs FDA and DEA to accelerate ibogaine research, fast-track clinical trials, and create pathways for Right to Try access [Ref 46, via Kozlov Nature 2026]
- **⚠ FLAG:** Legal status in US is rapidly evolving. Confirm current federal status with DEA scheduling database before publication.

### International
| Country/Region | Status |
|---|---|
| Mexico | Unscheduled; physician-supervised administration lawful; most international ibogaine clinics operate here |
| Brazil | Licensed clinics under ANVISA oversight |
| New Zealand | Class C controlled drug; prescription required |
| Netherlands | Therapeutic use permitted; no prohibition; several licensed clinics |
| South Africa | Medical supervision required; not prohibited |
| Costa Rica | Unregulated but openly practiced |
| United Kingdom | Not licensed; monitored by NPIS [Ref 4]; classified as a controlled substance |
| European Union | Varies by member state; generally not approved |
| Gabon | National heritage plant; wild harvest export banned (2019); cultivation permitted with Ministry approval [Ref 54] |

**⚠ FLAG:** Low confidence in exact EU member-state-level scheduling. UK status as controlled substance needs verification against current Misuse of Drugs Act schedules.

### International Treaties
Ibogaine is not listed in the schedules of the **1961 Single Convention on Narcotic Drugs**, the **1971 Convention on Psychotropic Substances**, or the **1988 UN Drug Convention**. Therefore, *Tabernanthe iboga* and ibogaine have no international treaty-mandated scheduling — national laws govern independently. This explains why countries like Mexico and Netherlands can permit ibogaine use legally.

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## Clinical Trials

| NCT ID | Title | Status | Phase | Condition | Sponsor |
|---|---|---|---|---|---|
| **NCT04313712** | MISTIC — Magnesium-Ibogaine for TBI/PTSD | Completed | N/A (observational) | TBI, PTSD, depression, anxiety | Stanford University |
| **NCT04003948** | Preliminary Efficacy and Safety of Ibogaine for Methadone Detoxification | Completed | Phase 2 | Drug Dependence, Opioid Dependence | ICEERS |
| **NCT06810765** | Trifecta Research Study | Withdrawn | Phase 2 | PTSD, Cognitive Dysfunction, TBI | Johns Hopkins University |

**Note:** Multiple additional ibogaine studies are underway or planned through MAPS, academic centers, and commercial sponsors following the 2025–2026 Texas appropriation and federal executive order. ClinicalTrials.gov search returned only 3 results; additional trials may be registered under related compound names (noribogaine, oxa-noribogaine, tabernanthalog).

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## Community Feedback Analysis

**No community feedback submitted** in the brief's Part A2. No feedback items to assess.

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## Gaps & Flags

### Safety-Critical Gaps
1. **⚠ Dose values not fully verified from published controlled RCT:** The 10–20 mg/kg therapeutic dose range derives from open-label observational studies and case series, not placebo-controlled trials. No standardized dose-response data confirmed.
2. **⚠ Traditional Bwiti doses:** Quantified alkaloid intake during Bwiti initiation ceremonies is absent from the published literature. "Hundreds of grams of root bark" is reported but unverifiable in mg-equivalent terms.
3. **⚠ Human LD50:** Not established. Rat NOAEL is 25 mg/kg (i.p.); anti-addictive doses in rats (40 mg/kg) are below the neurotoxic threshold. Human toxicity threshold is undefined.
4. **⚠ Herb–drug interaction case reports:** Many listed interactions are mechanism-based (CYP2D6, QT prolongation) rather than backed by individual clinical case reports. The CYP2D6 interaction (paroxetine study [Ref 15]) is clinical-trial confirmed. Others are extrapolated from mechanistic data.
5. **⚠ Serotonin syndrome risk:** No retrieved clinical case report of ibogaine-induced serotonin syndrome. Mechanism-based concern only.
6. **⚠ Heavy metals and contaminants:** No published analytical data on heavy metal (lead, cadmium), pesticide, or mycotoxin contamination of commercial iboga products.

### Data Absent from Published Literature
7. **Drug test detectability on standard panels:** Standard immunoassay panels do not detect ibogaine; confirmed via LC-MS methods [Ref 41]. No specific panel names or immunoassay cross-reactivity data found.
8. **Ibogamine, tabernanthine, and coronaridine pharmacodynamics in humans:** Largely uncharacterized; in vitro data only.
9. **Traditional-use-only evidence:** Sections on Bwiti ceremonial dosing, preparation methods, and phenomenological descriptions rely on ethnographic accounts without controlled pharmacological verification. **Flagged for human review.**
10. **Alkaloid content across cultivars and regions:** Quantified data on ibogaine variability by geographic origin, plant age, and part collected exists in commercial product analysis [Ref 31] but not from systematic botanical surveys of wild *T. iboga* populations.

### Unresolved/Needs Clarification
11. **UK legal status:** Needs verification against current Misuse of Drugs Act schedules. NPIS case series implies it is used (not licensed) in UK, but specific schedule placement unconfirmed via API.
12. **Lotsof's 1962 discovery:** Referenced in multiple secondary sources [Ref 8] but no primary documentation retrieved via API.
13. **1901 first alkaloid isolation (Landrin/Dybowsky):** Referenced in secondary literature [Alper 2001, Ref 28 context] but not directly verified via structured API search.
14. **Ibogaine's DEA scheduling as Schedule I in 1967:** Widely reported but not confirmed via DEA primary source in this research. Flag as moderate confidence — consistent across multiple sources.
15. **Interactions with specific MOUD:** The clinical risk when stopping methadone for ibogaine is real (Terasaki 2026 [Ref 37]) but quantified data (overdose incidence) are absent.
16. **Oneiric classification controversy:** Underwood et al. 2021 [OpenAlex] debates whether ibogaine experience should be classified as "oneirophrenic" vs. "holotropic." Traditional-use literature uses "oneirogen" as the classifier. Resolution depends on phenomenological criteria unavailable from structured PubMed/OpenAlex searches.