Trends of Fentanyl and Oxycodone Use in Australia (2018–2022) in National Prescription and Wastewater Data Sets

Triangulating complementary data sources can provide a more complete picture of population-level opioid use trends, both spatially and temporally. This study aimed to evaluate trends in fentanyl and oxycodone use in Australia from 2018 to 2022 using two data sources: Pharmaceutical Benefits Scheme (PBS) dispensing data and wastewater-based epidemiology (WBE), and to assess their agreement. Wastewater samples from 57 wastewater treatment plants, covering all Australian states and territories, were analyzed for biomarkers of fentanyl and oxycodone to estimate consumption. PBS claims were also converted to consumption and spatially mapped to wastewater catchments, enabling site, state, and national comparisons with WBE data. Spatially, PBS and WBE estimates showed better alignment for fentanyl than for oxycodone at both the site and state/territory levels. Temporally, there were strong correlations between PBS and WBE data for both opioids, particularly for fentanyl. PBS and WBE trends had similar decreasing rates of use of the two opioids over time. Fentanyl consumption decreased by 0.29 mg/day/1000 people per year according to PBS data, and by 0.31 mg/day/1000 people per year based on WBE estimates. Corresponding values for oxycodone were 15.36 mg/day/1000 people and 16.85 mg/day/1000 people. By integrating these complementary data sets, our study provides strong evidence of the declining trend of fentanyl and oxycodone use in Australia after stricter prescription regulation. WBE and dispensing data provide a powerful framework for comprehensive opioid monitoring to inform targeted public health interventions.