A randomized trial of adding fluoxetine to a naltrexone treatment programme for heroin addicts

Abstract

Aims. The purpose of the study was to assess whether fluoxetine would enhance retention in a naltrexone (NTX) treatment programme. Design. Randomized clinical trial. Setting. The clinical trial was conducted in two Drug Dependence Centres (DCs) of the Basque Country, Spain over a 1-year period. These DCs routinely used naltrexone as part of their treatment. Participants. A total of 112 heroin addicts included in a naltrexone treatment programme were randomly allocated to two groups of 56 patients each. Intervention. One group received 20 mg/24 h of fluoxetine for the first 6 months, while the remaining 56 patients were used as controls. No placebo was used. Measurements. Retention rates and hazard functions were estimated. The risk difference and relative risk were also calculated at 6 and 12 months. Findings. The survival functions showed significantly higher retention rates in the fluoxetine group than among the controls. The risk difference at both 6 months (RD6 = 0.23, CI 95% = 0.06-0.42) and 12 months (RD12 = 0.21, CI 95% = 0.09-0.39) favoured the fluoxetine group, with a greater dropout risk at both times among the controls (RR6 = 1.81, CI 95% = 1.11-2.94; RR12 = 1.46, CI 95% = 1.04 = 2.04). Conclusions. The study showed that the combination of fluoxetine and naltrexone produced significantly greater retention than in patients given only naltrexone. Placebo-controlled trials are warranted to assess how far this reflects a specific pharmacological effect.