Methadone concentrations taken as indicating deaths due to overdose need to be reviewed

EDITOR,—We are concerned that recent reports of death from methadone overdose may be greatly exaggerated owing to the use of inappropriately low serum methadone concentrations in attributing cause of death.1 2

Alison Cairns and colleagues do not specify what was considered to be a fatal serum methadone concentration in the 90 cases reported from Manchester,1 but a recent study from Sheffield of deaths …