Effects of 18-methoxycoronaridine on acute signs of morphine withdrawal in rats.

Ibogaine, an alkaloid found in the root bark of the African shrub Tabernanthe iboga, has been claimed to interrupt opioid dependence in humans; in animals, it has been shown to inhibit morphine self-administration and to attenuate signs of morphine withdrawal. However, ibogaine has some neurotoxicity, and because of this, efficacious and safer congeners of ibogaine have been sought, 18-Methoxycoronaridine (18-MC), a novel iboga alkaloid congener, has been shown, in animals, to mimic the effects of ibogaine on morphine self-administration without producing any ibogaine-like neurotoxiticity. In the present study, 18-MC was shown to attenuate five of seven signs of morphine withdrawal in rats. The data suggest that 18-MC will ameliorate symptoms of opioid dependence in humans.