Methadone-related deaths in Western Australia 1993-99

To describe methadone-related deaths in Western Australia from 1993 to 1999 and determine differences between deaths in methadone maintenance treatment (MMT) in the public and private sectors.

Review of coronial and clinical data for all cases identified by methadone detected from toxicological analysis of post-mortem samples between January 1993 and December 1999.

Eighty-four methadone-related deaths were identified. The majority (64%) were accidental; 74% of these were caused by a combination of drug effects. Overall, benzodiazepines were present in 74% of all decedents. Thirty-six (43% of all decedents) were registered in MMT when they died. Twenty-two decedents were registered with Next Step, of whom two died in the first week of treatment. In contrast, 14 decedents were registered with the CBMP, of whom eight died in the first week of treatment. The mortality rate in MMT peaked in 1998 (7.7 per 1,000 clients treated), one year after expansion into the private sector. A range of co-existing health conditions were present among decedents including: blood-bome viruses (BBVs), chronic pain/injury, asthma, epilepsy, diabetes, obesity, kidney disease, cardiac disease, pancreatitis, gall stones, paraplegia, cerebral palsy, schizophrenia, depression, suicidal ideation and arthritis.

Overall, methadone-related mortality did not increase significantly despite an increase in the population in MMT. Polydrug use, in particular the use of benzodiazepines in combination with methadone, was a major risk factor for premature mortality.

More attention is needed to reduce the use of benzodiazepines in combination with methadone. Decentralisation of methadone services into general practice must be carefully monitored to minimise the risk of mortality.