Kumar & Rajwal (Psychiatric Bulletin, January 2006, 30, 16-18) raise issues related to the adequate dose of methadone for treatment of opioid dependence. They reported that 54% of patients who participated in the survey used opiates in addition of their prescribed methadone. It would have been relevant to know the doses of methadone that this group were receiving compared with those that did not report additional opiate use. Low-dose methadone treatment has been strongly associated with poor outcomes in clinical studies (Reference Amato, Davoli and PerucciAmato et al, 2005). Observational studies and randomised controlled trials indicate that there is a linear dose-response relationship between methadone dose and heroin use. The likelihood of using heroin decreases as the dose of methadone increases (Reference Ward, Mattick, Hall, Ward, Mattick and HallWard et al, 1998). Evidence suggests that the appropriate methadone dose during maintenance treatment should be between 60 and 120 mg/day for most people (Department of Health, 1999), with some requiring significantly higher doses and some patients stabilising on lower doses. The prescription of methadone doses in this range results in greater retention of patients in treatment programmes and less heroin use while in treatment.

We would argue that the evidence clearly indicates that optimising methadone dose on an individual basis may reduce the number of patients who continue to use opioids in addition to their prescribed methadone. We suggest that supervised daily consumption should be normal practice until the patient is stabilised.