Trends in the use of Opioid Agonist Treatment in Australia, 2013-2022

September 2023

Ms Kendal Chidwick, Dr Chrianna Bharat, Associate Professor Natasa Gisev, Professor Michael Proinsias Farrell, and Scientia Professor Louisa Jane Degenhardt

Other investigators: 

Prof Robert Ali, University of Adelaide

Dr Deborah Zador, Centre for Alcohol and Other Drugs NSW Ministry of Health

Project description: 

Opioid agonist treatment (OAT) is one of the main treatments for people with opioid dependence. In Australia, there are currently four OAT formulations subsidised through the Pharmaceutical Benefit Scheme (PBS) - methadone, sublingual (SL) buprenorphine, SL buprenorphine-naloxone and long-acting injectable (LAI) buprenorphine. Listed on the PBS in September 2019, LAI buprenorphine provides an alternate OAT option that reduces the frequency of dosing visits compared to oral and sublingual OAT alternatives.

There are limited longitudinal data on patterns of opioid agonist treatment (OAT) in Australia. It is also unclear how the introduction of long-acting injectable (LAI) buprenorphine in 2019 and the COVID-19 pandemic impacted OAT accessibility. It is also not known to what extent real-world dosing intervals for LAI buprenorphine align with recommended guidelines.

You can find NDARC's technical reports on this project here.

You can also see our report on real-world dosing intervals of long-acting buprenorphine for opioid agonist treatment by clicking this link. 


This project aims to:

1. Examine trends in the estimated number of clients on all OAT medicines in Australia between 2013 and 2022, and

2. Examine variation in the estimated number of OAT clients by jurisdiction, remoteness, socio-economic status and setting.

3. Estimate real-world dosing intervals for monthly LAI buprenorphine.

Design and Method 

This project used monthly sales data to describe 10-year trends in the use of OAT medicines nationally and at the state and territory level. All OAT medicines (methadone, sublingual (SL) buprenorphine, SL buprenorphine-naloxone and LAI buprenorphine) sold in Australia between 2013 and 2022 were included. The total number of units sold each month was used to estimate the number of clients receiving OAT per month, based on average doses. Absolute counts of clients and rates of clients per 10,000 population were estimated per month, overall and by formulation, jurisdiction, remoteness, socioeconomic status and setting. A chart review of three Australian OAT providers verified that the LAI buprenorphine dose estimates used in this study aligned with real-world LAI buprenorphine dosing schedules.

Funding support provided by the Australian Government Department of Health and Aged Care, the ASCEND NHMRC Program Grant and Indivior PLC, through an Externally Sponsored Collaborative Research grant.


It is anticipated that the findings of this project will help to inform the post market surveillance of PBS OAT medicines.