A randomized, double-blind, placebo-controlled trial of long-acting risperidone in cocaine-dependent men.

OBJECTIVE

There is no approved pharmaco-therapy for cocaine dependence. Risperidone is an atypical antipsychotic drug with combined dopamine-2/serotonin-2 (D(2)/5-HT(2)) antagonist activity that has been effective in reducing cocaine use in some animal studies. We tested the efficacy of a long-acting, injectable preparation of risperidone on cocaine use in active cocaine users.

METHOD

Thirty-one cocaine-dependent men who met DSM-IV diagnostic criteria for current cocaine dependence entered a 12-week, randomized, double-blind, placebo-controlled trial of intramuscular risperidone, 25 mg every other week. The primary outcome measure was cocaine use as measured by urinary concentration of cocaine metabolites. Secondary outcomes were self-report of cocaine use and craving, depressive symptoms as measured by the Hamilton Rating Scale for Depression (HAM-D), and adverse events. Participants were recruited during a 12-month period from October 2005 to September 2006.

RESULTS

Both groups reduced their cocaine use during the study. There were no between-group differences in the primary measure of cocaine use (urinary metabolites [F = 0.7, p = .41]) or on craving measures. Those assigned to risperi-done reported significantly worsened depressive symptoms (mean +/- SD HAM-D change scores: +7.4 +/- 8.8 vs. -2.3 +/- 5.8, respectively, F = 7.5, p = .018) and gained significantly more weight (mean weight change: +6.3 +/- 9.4 lb vs. -4.0 +/- 8.9 lb, respectively, F = 4.65, p = .044) than those assigned to placebo.

CONCLUSION

Treatment with long-acting injectable risperidone in active cocaine users was not associated with reduction in cocaine use or craving and was associated with worsening of depressive symptoms and weight gain.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00385801.