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


James Shearer
National Drug and Alcohol Research Centre
University of New South Wales
Sydney, NSW 2052
E-mail: j.shearer@unsw.edu.au


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.