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 after 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). No 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 not increase these effects. Additional cocaine doses, however, did increase ratings of "bad drugs 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.

CONCLUSION

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.