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Your review on methadone and buprenorphine treatments casts doubt upon their effectiveness in general practice due to a lack of controlled research in the community.1 By the same standard, we should not be able to treat diabetes, depression or arthritis in general practice. Community, rather than specialist treatment is widely regarded as preferable for chronic conditions and it is the only feasible means of treatment outside metropolitan areas. Furthermore, adequate coverage of drug using populations in treatment cannot be achieved without extensive involvement of general practice-based treatment. The quality of clinic-based care is also quite variable.2
Despite giving 56 references, these authors fail to cite the many peer-reviewed descriptive and comparative reports of addiction treatments in general practice.3-8 Yet they quote a small British study of people on low methadone doses (average 43.5 mg, range = 20–80mg) and with high prevalence of heroin use (67%) which found that modestly higher doses of methadone (average increase of 14.5 mg) increased their heroin craving and lowered feelings of wellbeing.9 This study, never replicated, stands in stark contrast to strong evidence in multiple papers that higher doses, up to 100 mg daily, are associated with less heroin use.10-11 The authors allude to inadequacies of methadone treatment in parts of the UK yet they fail to point out the seriousness of this neglect, with average doses as low as half the usual effective daily dose of 60–120 mg, generally given without supervision.
We should all have confidence in Cochrane reviews which find that when given in sufficient doses with appropriate levels of supervision and counselling, both methadone and buprenorphine maintenance treatments are associated with major reductions in illicit drug use.12 There are also substantial improvements in general health and other important social and economic benefits including less blood borne viral infections. For methadone this involves supervised starting doses (for example, 30 mg daily) with gradual increases as indicated clinically.13 Buprenorphine can be equally successful in general practice settings where it can be very rewarding for those prepared to be involved in treating opiate dependent patients using these modalities.
Like a previously published Cochrane review,1 our synthesis of the international literature on community maintenance for treating opiate dependence2 supports the effectiveness of methadone and buprenorphine in reducing illicit opiate use and promoting retention in treatment. Our study adds to the Cochrane review by focusing on how effectiveness is influenced by the setting in which maintenance treatment is delivered, by the intensity of treatment, and by the provision of additional medical and psychosocial services.
To date, research primarily relates to patients receiving maintenance treatment in outpatient clinics. Recently, community maintenance has been extended to general practice in a number of countries including Australia and France.3 Although high-quality evidence is sparse, our review suggests that treatment with methadone or buprenorphine in general practice could be effective in patients who meet criteria of sufficient clinical stability and when provided by primary care physicians who have appropriate training. However, in an era of evidence-based medicine, there is a need for randomised controlled trials that properly evaluate community maintenance of opiate dependence in general practice. This is particularly true for conditions such as drug misuse, in which pharmacological treatment is only one component of effective therapy.
Our review has highlighted the daily doses at which methadone and buprenorphine are effective. Trials have suggested that the minimum effective daily maintenance dose may be 50 mg for methadone and 8–16 mg for buprenorphine. Higher doses of methadone and buprenorphine appear to be more effective at enhancing treatment retention and reducing illicit opiate use. Higher doses of buprenorphine have been shown to attenuate heroin craving, but the evidence relating to methadone is more equivocal.4,5
We and other authors have noted the issue of underdosing of methadone in the UK in our review and other publications.2,6,7 A recent survey of prescribing practices of general practitioners in Scotland revealed that only 58% of GPs used methadone doses in the recommended range.6 We believe that underdosing of methadone in the UK has been recognised for some time now, but that the difficulty lies in how to change clinical practice. UK guidelines need to clearly reinforce the message that higher doses of methadone are more effective. As guidelines alone are unlikely to change clinical practice, various strategies to disseminate and implement guidelines need to be explored.