G. Cape

Ibogaine is a psychoactive substance that may reduce opioid withdrawal symptoms. This was the first clinical trial of noribogaine, ibogaine’s active metabolite, in patients established on methadone opioid substitution therapy (OST). In this randomized, double-blind, placebo-controlled, single ascending dose study, we evaluated the safety, tolerability, and pharmacokinetics of noribogaine in 27 patients seeking to discontinue methadone OST, who had been switched to morphine during the previous week. Noribogaine doses were 60, 120 or 180mg (n = 6/dose level) or matching placebo (n = 3/dose level). Noribogaine was well tolerated. The most frequent treatment-emergent adverse events were non-euphoric changes in light perception at ∼1h post dose, headache and nausea. Noribogaine had dose-linear increases for AUC and Cmax, and was slowly eliminated (mean t_1/2 range 24–30h). There was a concentration-dependent increase in QTcI (0.17msec/ng/mL) with largest observed mean effect of ∼16msec, 28msec, and 42msec in the 60mg, 120mg, and 180mg groups, respectively. Noribogaine showed a non-statistically significant trend to decrease total scores in opioid withdrawal ratings, most notably at the 120mg dose, however the study design may have confounded evaluations of time to resumption of OST. Future exposure-controlled multiple-dose noribogaine studies are planned that will address these safety and design issues.

Glue, P., Cape, G., Tunnicliff, D., Lockhart, M., Lam, F., Hung, N., … & Howes, J. (2016). Ascending single‐dose, double‐blind, placebo‐controlled safety study of noribogaine in opioid‐dependent patients. Clinical Pharmacology in Drug Development. http://dx.doi.org/10.1002/cpdd.254
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