Novel psychoactive substances in Australian emergency departments: implications for public health practice from multi-centre prospective toxicosurveillance across five states, 2022–2023

Background: Comprehensive toxicology testing of emergency department (ED) presentations has become a prominent data source on novel psychoactive substances (NPS) in Australia. We describe the type and frequency of analytically confirmed NPS across five Australian states and 28 EDs between 2022 and 2023. Methods: This is a prospective series of ED presentations with at least one confirmed NPS detection identified by the Emerging Drugs Network of Australia (EDNA) and Emerging Drugs Network of Australia Victoria (EDNAV). De-identified demographic and toxicology data were extracted for analysis. Results: At least one NPS was detected in 646 ED presentations. Total detections was 1044 across 59 different compounds. The median age was 26 years (range 16–90 years) and 464 (71.8 %) were male. Benzodiazepine-type NPS comprised over three-quarters of all NPS positive cases (526, 81.4 %), bromazolam being most frequent (290, 44.9 % total cases). Twenty-four different novel stimulants were detected across 88 (13.6 %) presentations, N,N-dimethylpentylone (52, 8.0 % total cases) the most common. Novel opioids, dissociatives and synthetic cannabinoid receptor agonists made up a small proportion of total NPS positive cases. These findings directly informed nine public health harm reduction communications by multiple state government authorities warning of high-risk NPS detections. Traditional illicit drug co-detections were common (520, 80.5 %), in particular methylamphetamine (404, 62.5 %). Conclusion: Drug intelligence data generated in an acute harm setting such as the ED can provide early warning of drugs of concern circulating in the community, including NPS. This facilitates rapid community responses to reduce harm and inform subsequent public health responses.