Methadone-related overdose deaths in South Australia, 1984-1994. How safe is methadone prescribing?

Abstract

<h4>Objective</h4>To assess the safety of prescribing of methadone tablets and syrup in South Australia by investigating overdose deaths of patients using prescribed methadone and non-patients using illegally obtained methadone.<h4>Design</h4>Surveillance study of deaths related to methadone overdose, 1984-1994.<h4>Data sources</h4>Coroner's Office and the Therapeutic Goods Section of the South Australian Health Commission.<h4>Results</h4>Per capita prescription of methadone tablets for chronic pain in South Australia was the highest in Australia in 1994. A large increase in deaths, due mainly to methadone tablets prescribed for chronic pain, occurred in 1993-1994. Illegal diversion of methadone to non-patients was responsible for half of the deaths during these two years. Deaths from overdoses of methadone syrup prescribed in maintenance therapy for drug dependence declined from 1984 to 1994. The relative risk for patient deaths due to methadone tablets versus methadone syrup was estimated to be 7.29 (95% confidence limits, 2.15-31.48). Psychotropic drug combinations were present in 86% of deaths.<h4>Conclusion</h4>The methadone syrup program for drug dependence remains relatively safe. Our data raise concerns about prescribing methadone tablets for chronic pain. Better prescriber education and accountability, patient assessment and supervision and advice to patients about concurrent use of alcohol and benzodiazepines are needed.