Self administration of cocaine in monkeys receiving LAAM acutely or chronically

Polydrug abuse remains a common problem among opioid abusers as well as patients in opioid maintenance programs. Although cocaine abuse has been reported in patients receiving methadone, the incidence of cocaine use in patients receiving l-alpha-acetylmethadol (LAAM) has not been well established. The goal of this study was to determine whether acute or chronic administration of LAAM modified the reinforcing effects of cocaine using a self-administration procedure in rhesus monkeys. Four monkeys responded under a fixed ratio (FR) 30 schedule to receive i.v. infusions of cocaine (0.0032-0.32 mg/kg/infusion) in the absence of other treatment, after acute LAAM administration (0.1-1.0 mg/kg, s.c.), and during daily administration of 1.0 mg/kg of LAAM. Cocaine maintained self-administration responding that exceeded responding maintained by saline; acutely administered LAAM had small and variable effects on self administration of cocaine. Daily LAAM administration increased the number of infusions received of at least one dose of cocaine. These studies indicated that LAAM administration did not attenuate the reinforcing effects of cocaine, suggesting that LAAM would not likely alter cocaine abuse in patients undergoing treatment for opioid abuse.