Combined naloxone/methadone preparations for opiate substitution therapy.

Every opportunity should be used to reduce the risk of HIV-1 infection and transmission among intravenous drug users (IVDUs). Methadone maintenance is widely accepted to keep the drug user away from risk-laden practices and to stop intravenous drug use. In order to minimize the diversion and intravenous abuse of methadone in maintenance programs, the effects of a combined naloxone/methadone preparation through oral intake and the effects of an intravenous administration were tested. In opiate addicts, the intravenous administration of this mixture caused a severe withdrawal syndrome lasting for 15 to 30 minutes. The oral administration of this combination was indistinguishable from methadone alone. It is argued that this combination therapy prevents the intravenous abuse of methadone in maintenance programs.