Chalabianloo F, Fadnes LT, Høiseth G, et al. Substance Abuse Treatment, Prevention, and Policy. 2021;16:1-8. Read full paper

This paper is described as a naturalistic prospective cohort study in 83 patients who were receiving methadone in clinics in Bergen, Norway. The aim was to investigate how self-perceived opioid withdrawal symptoms are related to serum methadone concentrations and their potential role in clinical decisions on dose adjustment. The mean age of participants was 45 years and one-third of the patients were women. The mean methadone dose was 97mg daily and the mean score on the Subjective Opiate Withdrawal Scale (SOWS) was 9.

Almost half reported some subjective opioid withdrawal symptoms — from mild to moderate level — and people with the lower serum concentration-to-dose ratios of methadone reported more of these withdrawal symptoms (p= 0.039). Other factors associated with lower methadone concentrations included a lower subjective opioid withdrawal scale score, subjective symptoms of anxiety, bone and muscle aches, restlessness, and shaking, as well as use of heroin and alcohol.


How do you adjust methadone doses? A collaborative person-centred approach is a good place to start and arbitrary limits should be treated with caution. Methadone treatment is pock-marked with ideological influences and we’d be naïve to think that was no longer the case. It is one of the most fascinating aspects of methadone treatment — considering this is just a single medication there is incredible variation in individual responses and scope for subtle tailoring. Given the potential for socio-political influence on methadone dose, not least the important role of stigma, any further evidence on this dose adjustment is very welcome.

It is worth fleshing out the finding that lower serum concentration-to-dose ratios were found in people with more subjective withdrawal symptoms. This was a ratio — not the absolute dose of methadone — and, indeed, these people were getting comparable doses of methadone. There are undoubtedly people who metabolise methadone quite differently. Sometimes dose increases will work but other options may need to be considered including split daily dosing and, where the option exists, alternative opioids. The authors do acknowledge that lower serum concentrations could also be linked to diversion of take-home doses.

The authors write that in practice there is a wide range of approaches to methadone dose adjustment and we know that even in the same team in the same service this can vary widely between clinicians. The evidence on this is very sparse. This study does show an association between methadone concentrations and subjective opioid withdrawal symptoms. In practice this means that one can, with more confidence, use the experience of withdrawal symptoms as reported to us to make changes to doses.

Article taken from our latest Clinical Update, edited by Dr Euan Lawson (Editor of the British Journal of General Practice). To read the full Clinical Update please become a Premium CPD Member.

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