Metadone maintenance (MMT) at different dosages for opioid dependence: a Cochrane review

Background Even if MMT at high dosage is recognised to be the best therapy in reducing illicit opioid use and promoting longer retention in treatment, at present day the organisation and regulation of the methadone maintenance treatment varies widely. Aim To present the result of a systematic review about the efficacy of different dosages of MMT in relation to retention in treatment, opioid and cocaine use criminal activity and patient mortality. Methods Search strategy Sources: MEDLINE, EMBASE, ERIC, Controlled trials register (CCTR), Register of the drug and alcohol group (CDAG), letter to the authors of the selected trials or to experts, reviews of reference list, pharmaceutical industries (Molteni, Zambon), Psychinfo. Strategy: CDAG strategy, specific MESH strategy. Selection criteria Storage of result search and analysis on ProCite to exclude articles not related to the subject. Exclusion of not pertinent studies by reading abstracts and applying specific exclusion criteria. Assessment of the studies not excluded above by using the CDAG’s checklist. Assessment of the internal quality. Data collection & analysis Extraction by two reviewers, according to a standardised checklist. Discrepancies resolved by a third reviewer. RevMan software was used for analysis. Results Studies excluded: 22; included: 21 (11 RCTs, 10 CPSs). Retention rate – RCT: high vs. low doses at shorter follow-ups: RR=1.36 [1.13,1.63], and at longer ones: RR=1.62 [0.95,2.77]. Opioid abstinence – RCT: high vs low ones: RR=1.59 [1.16,2.18]. Cocaine abstinence – RCT: high vs low ones: RR=1.81 [1.15,2.85]). Conclusions Methadone dosages ranging from 60 to 100 mg/day are more effective than lower dosages in retaining patients and in reducing use of heroin and cocaine during treatment. To find the optimal dose is a clinical ability, but clinician must consider these conclusions in treatment strategies.