HARCP Archives

Browse by article

Browse by volume

Heroin Addiction and Related Clinical Problems: 2005, 07, 2 (pages: 5 - 10)

Methadone maintenance treatment and mood disturbances: Pharmacological and psychological implications

Dyer K. R.

Summary: The rationale for methadone maintenance is to stabilise the pharmacological condition of illicit opioid users, thereby providing an opportunity to normalise health and social functioning. The extent to which methadone is effective for any given individual may be governed by the degree to which methadone prevents opioid withdrawal symptoms, in the absence of significant opioid adverse effects. Mood and anxiety disorders are common within opioid-dependent patients, and there is some evidence to suggest that these disorders may affect the response to treatment. This paper will describe the relationship between plasma (S)- and (R)- methadone concentration, opioid withdrawal, and state and trait mood disturbance. A series of studies have demonstrated that significant mood changes occur in response to changes in plasma methadone concentration, and that these mood changes are more pronounced in those who experience opioid withdrawal. Concentration-effect relationships suggest that relatively small changes in plasma concentration result in significant mood change. An important implication from this research is that consideration of individual differences in methadone pharmacokinetics is necessary for understanding the aetiology of observed mood disturbance among methadone dependent patients. Implications for the clinical management of methadone patients, including the assessment of, and response to, mood disorders and the implications for therapeutic drug monitoring within methadone maintenance programs will be discussed.