Pilot randomized double blind placebo-controlled study of dexamphetamine for cocaine dependence

Aims To establish the feasibility of conducting a placebo-controlled clinical trial of dexamphetamine replacement therapy for cocaine dependence and to obtain preliminary data. Design Double-blind randomized placebo-controlled trial. Participants Thirty cocaine-dependent injecting drug users. Intervention Subjects were assigned randomly to receive 60 mg/day dexamphetamine (n=16) or placebo (n=14) for 14 weeks. Measurements Immunoassay and mass spectrometric techniques were used to identify cocaine metabolites in urine. Subjects were screened using the Composite International Diagnostic Interview and DSM-IV The Opiate Treatment Index, Brief Symptom Inventory, Severity of Dependence Scale and visual analogue craving scales were used to collect pre- and post-self-report data. Findings Treatment retention was equivalent between groups; however, outcomes favoured the treatment group with no improvements observed in the placebo control group. The proportion of cocaine-positive urine samples detected in the treatment group declined from 94% to 56% compared to no change in the placebo group (79% positive). While the improvements were not significant between groups, within-group analysis revealed that the treatment group reduced self-reported cocaine use (P=0.02), reduced criminal activity (P=0.04), reduced cravings (P<0.01) and reduced severity of cocaine dependence (P<0.01) with no within-group improvements found in the placebo group. Conclusions A definitive evaluation of the utility of dexamphetamine in the management of cocaine dependence is feasible and warranted.