Methylamphetamine toxicity and its involvement in death: A retrospective observational study of deaths reported to the Victorian Coroner, Australia.

A retrospective observational study of Victorian deaths involving MA between 2010 and 2019 was conducted to determine the prevalence and contribution of methylamphetamine (MA) toxicity to death in the absence of other factors. Demographics, autopsy findings, toxicology, and the cause of death were reviewed. Coronial cases were categorized into five groups: deaths due to MA toxicity in the absence of other factors (Group A1); deaths due to MA toxicity in the setting of other potentially contributing factors (Group A2); deaths due to MA toxicity in the setting of significant natural disease (Group B); deaths primarily due to multiple-drug toxicity (Group C); and deaths primarily due to natural causes (Group D). There were 506 deaths involving MA categorized into Group A1 (n = 1, 0.6%), Group A2 (n = 8, 1.6%), Group B (n = 28, 5.5%), Group C (n = 229, 45%), and Group D (n = 240, 47%). Significant natural disease was prevalent among deaths involving MA and mainly concerned forms of cardiovascular disease (n = 277, 55%). The MA concentration in the one death included in Group A1 was 2.1 mg/L. The median MA concentrations of Group A2 (1.6 mg/L) and Group B (0.5 mg/L) were significantly higher than Group C (0.2 mg/L) and Group D (0.2 mg/L). Additionally, many other toxicologically significant drugs were detected and mostly comprised of central nervous system depressants. Deaths due to MA toxicity in the absence of other factors were rare despite the greater availability of crystal MA in the Australian community. The study highlights the interpretative challenges of MA blood concentrations and the continuing harms of this drug in Australia.