Oxycodone use in Australia dropped 45% after policy changes to opioid prescribing

Between 2018 and 2020, Australia implemented policy changes to improve the quality and safety of opioid prescribing, with a specific focus on oxycodone.  A new study led by The University of Queensland (UQ) using wastewater analysis has determined that oxycodone consumption in Australia dropped by 45% from 2019 to 2020, coinciding with those national policy changes.

In November 2019, the Australian National Prescribing Service launched a federal initiative to improve opioid prescribing.  The initiative involved alerting high-prescribing clinicians that their opioid prescribing practices were outside typical ranges for that practitioner group (2019), providing training in opioid prescribing (2019), reducing the oxycodone package size (2020), and adding warning messages to oxycodone packaging (2020).

The study used wastewater-based epidemiology to estimate the quantity of oxycodone consumed by a community by sampling the community’s sewage as it flowed into a wastewater facility and measuring the levels of oxycodone and its metabolite, noroxycodone, excreted in urine.

For this study, the Australian National Wastewater Drug Monitoring program (NWDMP) collected and analysed 6,999 samples from over 50 wastewater treatment plants across Australia from April 2017 to April 2023.  The results of the analysis are listed below.

• Oxycodone use initially increased from 78 mg/day/1000 people in April 2017 to 120 mg/day/1000 people in August 2019.  This 52% increase occurred before the federal initiative to improve opioid prescribing began.
• Oxycodone use then decreased from 120 mg/day/1000 people in August 2019 to 65 mg/day/1000 people in December 2020.  This 45% decrease coincided with the introduction of prescribing guidelines in 2019 and oxycodone packaging changes in 2020.
• Oxycodone use showed a minor 2.4% increase from December 2020 to April 2023.

Lead author Dr. Rory Verhagen from UQ’s Queensland Alliance for Environmental Health Sciences explains, “The main finding from this study was that a big reduction in oxycodone use between 2019 and 2020 coincided with the introduction of national clinical and regulatory changes intended to reduce pharmaceutical opioid use.  It is likely that the combination of smaller package sizes and educational initiatives in 2019 and early 2020 reduced consumption of oxycodone in Australia.”

The reduction in oxycodone use has not been offset by an increase in heroin or fentanyl use in Australia.  NWDMP monitoring shows that throughout the study period, the consumption of heroin fluctuated without any clear trend while fentanyl followed a similar trend to oxycodone.

The study was conducted by researchers from The University of Queensland, the University of South Australia, and Queensland Health, Australia with primary funding from the Australian Criminal Intelligence Commission; it appears in the scientific journal Addiction.

Full citation for article: Verhagen R, Gerber C, Thai PK, Connor J, Loveday B, Bade R, O’Brien J, Jaunay EL, Simpson BS, Chan G, Hall W, Thomas KV, Mueller JF, Tscharke BJ.  Wastewater-based evaluation of the efficacy of oxycodone regulations in Australia. Addiction. 2024. DOI: 10.1111/add.16653.

Primary funding: The Australian Criminal Intelligence Commission and Queensland Health Australia provided financial support for this research.  Wastewater catchment mapping and sampling was conducted under an Australian Research Council Linkage Project (LP190101124, LP220100058).

Declaration of interests: None.