Naltrexone maintenance treatment for opioid dependence

Despite widespread use of naltrexone maintenance in many countries for more than ten years now (e.g., USA since 1984, UK since 1988) a sound documentation of the research on this drug is still missing.

To evaluate the effects of naltrexone maintenance treatment in preventing relapse in opioid addicts after detoxification.

We searched MEDLINE, EMBASE, CCTR and handsearched the "Bolletino per le Farmacodipendenze e l'Alcolismo"; contact was sought with pharmaceutical producers of naltrexone, with authors and other CRGs; references of obtained studies. Trials were reliably identified and data extracted. Date of most recent searches: June 1998.

All studies controlled for naltrexone; treatment of heroin addicts after detoxification with naltrexone. Studies were classified into three categories (high, moderate or low risk of bias) according to their methodological quality.

Reviewers evaluated data independently and analysed outcome measures taking into consideration adherence to and success of the study intervention. Data was extracted and analysed stratifying for the three categories of study quality. Where possible, meta-analysis was performed.

Eleven studies were included in this review, and not all of them were randomised. Meta-analysis could be done to a low degree only, because the studies and their outcomes were very heterogeneous. The result of this quantitative analysis was statistically poor, and so was the methodological quality of the included studies.

The available trials do not allow a final evaluation of naltrexone maintenance treatment yet. A trend in favour of treatment with naltrexone was observed for certain target groups, as described in the literature before. A well-done clinical trial is needed in order to get better evidence as soon as possible.