"Although ibogaine has been reported to effectively reduce drug cravings and withdrawal symptoms in addicts (Sheppard, 1994), its tremorigenic, hallucinogenic, neurotoxic, and cardiovascular side effects (see Alper, 2001) have prevented its approval as a treatment for addiction. On the other hand, 18-methoxycoronaridine, although not yet tested in humans, has no apparent side effects in rats, presumably because it is more selective pharmacologically than ibogaine."

Source

Pace, Christopher J., Glick, Stanley D., Maisonneuve, Isabelle M., He, Li-Wen, Jokiel, Patrick A., Kuehne, Martin E., and Fleck, Mark W., "Novel Iboga Alkaloid Congeners Block Nicotinic Receptors and Reduce Drug Self-Administration," European Journal of Pharmacology, Vol. 492, 2004, p. 159.