Background: Despite widespread use in many countries the evidence of tapered methadone's efficacy in managing opioid withdrawal has not been systematically evaluated.
Objectives: To evaluate the effectiveness of tapered methadone compared with other detoxification treatments and placebo in managing opioid withdrawal on completion of detoxification and relapse rate.
Search strategy: We searched: Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (January 1966 to December 2004), EMBASE (January 1988 to December 2004), PsycINFO (January 1985 to December 2004), and reference lists of articles. We also contacted manufacturers and researchers in the field.
Selection criteria: All randomised controlled trials which focus on the use of tapered methadone versus all other pharmacological detoxification treatments or placebo for the treatment of opiate withdrawal.
Data collection and analysis: Two reviewers assessed the included studies. Any doubt about how to rate the studies were resolved by discussion with a third reviewer. Study quality was assessed according to the criteria indicated in Cochrane Reviews Handbook 4.2. (Alderson 2004)
Main results: Sixteen trials involving 1187 people were included. Comparing methadone versus any other pharmacological treatment we observed no clinical difference between the two treatments in terms of completion of treatment, relative risk (RR) 1.12; 95% CI 0.94 to 1.34 and results at follow-up RR 1.17; 95% CI 0.72 to 1.92. It was impossible to pool data for the other outcomes but the results of the studies did not show significant differences between the considered treatments. These results were confirmed also when we considered the single comparisons: methadone with: adrenergic agonists (11 studies), other opioid agonists (four studies), chlordiazepoxide (study). Comparing methadone with placebo (one study) more severe withdrawal and more drop outs were found in the placebo group. The results indicate that the medications used in the included studies are similar in terms of overall effectiveness, although symptoms experienced by participants differed according to the medication used and the program adopted.
Authors' conclusions: Data from literature are hardly comparable; programs vary widely with regard to duration, design and treatment objectives, impairing the application of meta-analysis. The studies included in this review confirm that slow tapering with temporary substitution of long acting opioids, accompanied by medical supervision and ancillary medications can reduce withdrawal severity. Nevertheless the majority of patients relapsed to heroin use.