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

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.

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.

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.