A recent development in the treatment of opioid dependence is the introduction of long-acting injectable (LAI) formulations of buprenorphine. Listed on the Australian Pharmaceutical Benefit Scheme (PBS) in September 2019, LAI buprenorphine is administered via weekly or monthly subcutaneous injections, providing an alternative treatment option for opioid dependence that reduces the frequency of dosing visits and increases flexibility, compared to oral methadone and sublingual buprenorphine. There have been reports of variation in LAI buprenorphine's ability to maintain adequate symptom control between monthly doses, however, the average dosing interval (i.e., the number of days between doses) for LAI buprenorphine in observational or real-world settings, is currently unknown. Quantifying variation in dosing intervals, as observed in clinical practice, will help inform both the management of clients and the cost-effectiveness of LAI buprenorphine as a treatment option for opioid dependence.
This report uses monthly sales data to describe 10-year trends in the use of OAT medicines in Western Australia. All OAT medicines (methadone, sublingual (SL) buprenorphine, SL buprenorphine-naloxone and LAI buprenorphine) sold in Western 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.