Outpatient Initiation of 7-Day Injectable Buprenorphine: A Direct-to-Inject Case Series.

Background: Buprenorphine is an effective treatment for opioid use disorder, but it can be challenging to avoid withdrawal in the process of buprenorphine initiation. After the recent FDA approval of 7-day long-acting injectable buprenorphine, some clinicians have used this formulation to start patients on buprenorphine without a prior sublingual "test dose." Very little is known about the feasibility of this practice in an outpatient setting.

Cases: In this case series, we conducted a retrospective chart review of electronic health record data for all patients who were ordered 7-day long-acting injectable buprenorphine for a "direct-to-inject" initiation within a single public health system from January 1, 2024 to November 15, 2024. We excluded patients who received a cumulative dose of 4 mg or more of sublingual buprenorphine in the 24 hours before injection. We reported on chart-documented patient experiences after injection, whether patients returned to care, and retention on buprenorphine at 7- and 30-days post-injection. We identified 21 unique patients who received direct-to-inject buprenorphine in 22 attempts. In 17 (77%) attempts, the patient received no buprenorphine in the preceding 24 hours. In 5 (23%) attempts, patients received some buprenorphine in the preceding 24 hours (<4 mg) and/or had evidence of buprenorphine in a same-day urine drug screen. Patient experiences post-injection fit into 1 of 3 themes: "It felt fine" (n = 6), "I felt unwell but okay" (n = 13), and "It felt very rough" (n = 3). Most attempts resulted in buprenorphine treatment retention at 7 days (n = 17, 77%) and 30 days (n = 16, 73%) after injection.

Discussion: Direct-to-inject buprenorphine was generally well tolerated, with excellent retention on buprenorphine at 7- and 30 days post-injection. Further research is needed to evaluate the correlation between preinjection patient characteristics (time since last use, level of withdrawal) and post-injection patient experience of withdrawal.