Work

Outpatient initiation of direct-to-inject buprenorphine

Year: 2025

Type: article

Abstract: BACKGROUND: Fentanyl-involved overdose deaths have surged, yet buprenorphine remains underutilized for opioid use disorder (OUD) treatment, partly due to the risk of precipitated withdrawal during buprenorphine initiation. Direct-to-inject (DTI) buprenorphine using weekly long-acting injectable formulations may reduce this risk with a gradual and sustained rise in serum buprenorphine levels. OBJECTIVE: To evaluate 90-day treatment retention, withdrawal tolerability, and associated factors following DTI buprenorphine initiation across multiple outpatient safety-net settings. METHODS: We conducted a retrospective cohort study of 131 DTI initiations among 114 patients with OUD across San Francisco and Oakland safety-net clinics from March 2024 to May 2025. Patients were initiated on weekly long-acting buprenorphine. We assessed withdrawal severity in the first 24h and calculated continuous treatment retention at 7, 30, and 90 days using pharmacy and chart data. RESULTS: Mean age was 42 years; 79 % reported fentanyl use, and 67 % were unstably housed or unhoused. In the 24h after injection, 37 % experienced no withdrawal, 31 % experienced mild-moderate withdrawal, and 11 % experienced severe withdrawal, with 21 % missing data. Overall, 72 % continued buprenorphine beyond initial injection, with most transitioning to monthly formulations. Retention rates were 69 % at 7 days, 68 % at 30 days, and 43 % at 90 days. No demographic or clinical factors predicted 90-day retention. CONCLUSIONS: In this retrospective study, DTI buprenorphine initiation demonstrated favorable tolerability and retention in a high-risk population across diverse outpatient settings. This approach may offer a viable pathway to long-acting buprenorphine treatment for individuals using fentanyl who may not tolerate traditional initiation methods.

Source: Drug and Alcohol Dependence

DOI: 10.1016/j.drugalcdep.2025.113011