Utility of crossover designs in clinical trials: efficacy of desipramine vs. placebo in opioid-dependent cocaine abusers

Abstract

The utility of the crossover design in substance abuse research was examined in a 26-week, double-blind clinical trial that evaluated the efficacy of desipramine (0 or 150 mg/day) in 109 male and female cocaine- and opiate-dependent patients maintained on buprenorphine (12 mg/day) or methadone (65 mg/day). After being stabilized on buprenorphine or methadone (weeks 1-2), half of the patients were randomly assigned to receive desipramine for the first half of the trial and placebo for the second, with the order reversed for the second half. Analyses using hierarchical linear models (HLM) indicated that desipramine reduced the use of opiates only when administered at the start (rather than the middle) of the trial, whereas cocaine use was reduced when desipramine was introduced at either time.