Effects of "binge" use of intravenous cocaine in methadone-maintained individuals

Aims. To examine the effects of heavy cocaine use followed by abstinence. Design. During self-administration sessions, which occurred in the afternoon and again in the evening, participants could self-administer up to six doses of intravenous cocaine (32 mg/70 kg) at 14-minute intervals. All volunteers participated in a 2-day and a 3-day series of self-administration sessions (cocaine binges). Nb cocaine was available for at least 2 days following each cocaine binge. Participants. Five adult methadone-maintained cocaine abusers. Setting. Inpatient clinical research unit. Measurements. Cardiovascular and subjective effects. Findings. The first cocaine dose in a session produced substantial subjective and cardiovascular effects and, with the exception of blood pressure and ratings of "irritable", administering up to five more cocaine doses did nor increase these effects. Additional cocaine doses, however, did increase ratings of "bad drug effect" and decrease ratings of "I want cocaine": Maximal subjective and cardiovascular effects of cocaine did not vary across sessions on the same day or between days. Ratings of "depressed" and "miserable" were increased the first day after each period of cocaine use, and presentation of cocaine-related stimuli increased ratings of "I want cocaine" and "I want heroin" during cocaine abstinence. Conclusions. Acute tolerance developed to many of the effects of cocaine during a cocaine binge in methadone-maintained individuals, next-day residual changes in mood were subtle, and no prolonged effects of a cocaine binge were observed.