Retention rates with monthly depot buprenorphine in general practice in Melbourne, Australia

Opioid dependence is an important public health issue with high rates of relapse. This study, conducted in a suburban Australian general practice, reports treatment retention for patients on long-acting depot buprenorphine injections.

Patients were offered monthly buprenorphine depot from 11 December 2019 to 31 July 2020; data collection ceased on 30 November 2020. Overall retention at 168 days was estimated, and retention when discontinuation was defined as >2 or >4 weeks' delay between injections (2/4 WTD).

For 126 patients treated (mean age: 40.2 years [range: 20-65 years], 32% women, 98% with history of heroin dependence), the overall retention rate was 62% (53% and 40% using 2WTD and 4WTD definitions of discontinuation). Eleven patients returned to previous treatment; 10 patients with planned discontinuations were censored.

Depot buprenorphine supported more than half of patients to remain in treatment, while allowing some flexibility in dose interval. Predictive power is limited by the small sample and observational design.