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284
ANNALS NEW YORK ACADEMY OF SCIENCES
months. Ibogaine had been administered to opiate and cocaine addicts in Europe and
Central America through an informal self-help net~ork.~ Although promising, these
anecdotal reports from addict self-help groups have not been verified in controlled
clinical trials by established investigators. Although the precise neurochemical mecha-
nism(~) of action for ibogaine have only begun to be studied, it is important to em-
phasize that many therapeutic successes have arisen empirically. The anecdotal reports
of the effectiveness of ibogaine for the treatment of opioid and cocaine dependence
provide a basis for further studies of ibogaine as a pharmacotherapy for drug depen-
dence.
SAFETY CONSIDERATIONS
Ibogaine has a variety of dose-dependent pharmacological actions that may not be
relevant to its effectiveness for opiate detoxification and psychostimulant and opiate de-
pendence, but may influence considerations for safety. However, toxicological studies
conducted in primates have demonstrated that oral ibogaine administrations, given at
doses (5
x
25
mg kg-') recommended for the treatment of cocaine and opiate depen-
dence, appear to be safe and free of behavioral or cerebellar toxicity.60 The development
of ibogaine as an antiaddiction drug has been hindered due to uncertainties over po-
tential cerebellar neurotoxicity demonstrated in rat studie~.~~.~~ O'Hearn and MolliveP
showed that high doses of ibogaine (100 mg kg-' or
3
x
100 mg kg1) causes degenera-
tion of the cerebellar purkinje cells in rats. Molinari
et
~1.~'
reevaluated the dose effects
of ibogaine. In this study, a lower dose (40 mglkg) of ibogaine, one effective in reduc-
ing morphine and cocaine self-administration, displayed no degeneration above the
level seen in saline-treated controls. These observations suggested that the degenerative
and 'antiaddictive' properties of ibogaine reflect different actions of the drug.
Although the Phase I investigations by our group have not advanced recently, we
have had the opportunity to obtain additional safety data in persons receiving ibogaine
treatments abroad under controlled conditions. Baseline screening in these subjects in-
cluded a medical evaluation, physical examination, electrocardiogram (ECG), blood
chemistries, and hematological workup, as well as psychiatric and chemical depen-
dency evaluations. A total of thirty
(23
male,
7
female) drug-dependent subjects were
assigned to one of three fixed-dose treatments under open label conditions: 500 mg, 600
mg, and 800 mg ibogaine. Adverse effects were assessed by clinician side-effect ratings
and open-ended query. No significant adverse events were seen under these study con-
ditions. The most frequent side effects observed were nausea and mild tremor at early
time points after drug administration. Random regression of vital signs (respiration
rate, systolic and diastolic blood pressures and pulse) revealed no significant changes
across time or by treatment condition. White blood cell count, neurotrophil levels,
sodium or potassium levels were in the normal range. No significant changes from
baseline were seen for alanine aminotransferase (ALT), serum aspartate aminotrans-
ferase (AST) alkaline phosphatase (ALP), and y-glutamyl transpeptidase (GGT). In-
tensive cardiac monitoring demonstrated that no electrocardiographic abnormalities
were produced or exaggerated following ibogaine administration. These preliminary re-
sults demonstrate that single oral doses of ibogaine were well tolerated in drug-
dependent subjects, and that there were no significant problems with safety within this
dose range.
Concern over potential cerebellar toxicity6' compelled us to examine ibogaine's ef-
fects on postural stability, body tremor and appendicular tremor
(FIG.
4).
In the FDA
pharmacokinetic and safety trial studies, two doses of ibogaine (1 and
2
mg kg-') were
administered to
9
volunteers with histories of recent cocaine abuse. Static posturogra-
286
ANNALS NEW YORK ACADEMY OF SCIENCES
Static Posturography
(n=6)
=Eyes Open
a~yes Closed
Heel-to-toe, Open
m~eel-to-toe, Closed
Time (hrs)
D
Tremor (Arms Extended)
a
-,
Hz
(n=4)
75
I
11-2
Hz
h
m3-7
HZ
8
-
-8-15Hz
$
50
0
a
a,
.=
C
25
m
-
a,
c
0
0
2
4
6
Time (hrs)
phy with a portable bedside computerized platform was used to quantify body sway
while standing normally and in a heel-to-toe position with eyes opened and eyes closed.
Measurements were taken at baseline and every two hours following oral administra-
tions of ibogaine. Dynamic posturography measured functional limits of stability over
6
hr. Accelerometry was used to measure tremor of the hands at rest and with arms ex-
tended over the same time period. Whole body tremor, akinesia, and retropulsion were
measured with the NeurotestTM apparatus at baseline and
48
hr after drug administra-
tion. Both doses of ibogaine produced no clinically visible effects, but static posturog-
raphy revealed a trend (albeit not significant) toward increased body sway when sub-
jects stood in the heel-to-toe posture with eyes closed. Dynamic posturography and the
Neurotest measurements revealed no changes from baseline. Hand accelerometry did
MASH
et
al.:
IBOGAINE AS PHARMACOTHERAPY
287
not show any effects of ibogaine on tremor (at rest or with arms extended). However,
baseline measurements of tremor revealed quantitative differences between cocaine-
dependent patients and age-matched and drug-free control subjects. Power spectrum
analysis of these data revealed an increase in the 3-7-Hz range, supporting the hy-
pothesis that early cocaine abstinence may reflect a hypodopaminergic state." Similar
observations on patients receiving oral doses of ibogaine in a range of 10 to 30 mgtkg
in offshore clinical settings, failed to demonstrate any effects with Neurotest measure-
ments taken at 5 to
7
days post dose
(n
=
10; 8 male, 2 female; data not shown). In ad-
dition to the lack of posturographic abnormalities, clinical neurologic exams demon-
strated no evidence of permanent cerebellar ataxia in these subjects.
Our research group had the opportunity to conduct a neuropathological evaluation
on a female subject who had received 4 doses of ibogaine ranging from 10 to 30 mg kg-
over a period of 15 months. The last two administrations occurred in a Panamanian
hospital, approximately 25 days prior to her death from natural causes. Before receiv-
ing these last ibogaine treatments, the subject received a series of clinical evaluations
at the University of Miami School of Medicine. Her diagnoses at that time included:
1) opiate and cocaine dependence; 2) amenorrhea for 11 months;
3)
a history of
asthma; 4)
a
history of peptic ulcer disease; and 5) a history of hypertension. The gen-
eral physical exam was normal. Neurological examination (including magnetic reso-
nance imaging (MRI), electroencephalogram (EEG) and a Neurotest gait analysis for
cerebellar signs were normal. Urine toxicology was positive for cocaine, opiates, and
marijuana. She received two doses of ibogaine three days apart (10 mglkg and 20
mgtkg). Approximately one week later, she returned to Miami for follow-up neurolog-
ical evaluations. At that time, the patient was admitted to the hospital for the evalua-
tion of tremors. The examination revealed temperature 98, pulse 92, respirations 22,
and blood pressure 1601108. General physical exam was notable for "an ulcerative le-
sion on her right anterior thigh with
3
to 4 cm erythmatous area surrounding it and par-
tially healed." Repeat neurological exam at that time was grossly normal. She was
treated with clonidine and discharged. The patient went back to New York where she
was treated with diazepam for anxiety and poor sleep. She returned to Miami three
weeks later, where she complained to a friend that she had been having diarrhea and
vomiting since eating raw fish the previous night. Her vomiting progressively wors-
ened, but she did not seek medical attention. The subject died thereafter and was au-
topsied. The toxicology screen was positive for benzodiazepines only. Postmortem an-
tinuclear antibody (ANA) and rheumatoid factor were negative. The postmortem
autopsy revealed mesenteric artery thrombosis with small bowel infarction as the cause
of death, left renal cortical hemorrhagic infarcts, splenic infarct, a capsular hemorrhage
of the right ovary, and agonal aspiration of gastric contents. Comprehensive evalua-
tions of the histopathology revealed multiple microscopic arterial thrombi in several tis-
sues, although there was no evidence of arteritis whatsoever. These observations led to
the conclusion that the pathological picture was that of a generalized hypercoaguable
state. The pathological picture was most consistent with an infectious source (the leg
ulcer) producing a thrombotic process resulting in mesenteric artery occlusion and
death. This cause of death was more likely than an acute drug toxicity (which would
have occurred at 25 days after ibogaine administration).
Neuropathological evaluation revealed slight medullary neuroaxonal dystrophy and
an old focal meningeal fibrosis. There were no degenerative changes seen in the cere-
bellum; cerebellar Purkinje cells were normal and there was no evidence of any signif-
icant cytopathology or neurodegeneration in any other brain area
(FIG.
5). There was
no evidence of astrocytosis or microglial activation. The neuropathological analysis for
a human subject (NH) was important in light of the observations of O'Hearn and
M~lliver,~~ which demonstrated that at high doses, ibogaine administrations result in the