Importance Extended-release injectable buprenorphine may expand the reach of initiating medications for opioid use disorder in high-risk and hard-to-reach individuals who visit the emergency department (ED) and can be administered in low levels of withdrawal. Objective To compare the effect of ED-initiated 7-day extended-release injectable buprenorphine vs sublingual buprenorphine on treatment engagement at 7 days. Design, Setting, and Participants Multicenter randomized clinical trial enrolling adult patients presenting to the ED with untreated opioid use disorder and a Clinical Opiate Withdrawal Scale (COWS) score of 4 or higher across 29 EDs in the US from July 12, 2020, to August 21, 2024. Final follow-up was completed on October 24, 2024. Interventions Patients were randomized to receive a 24-mg injection of extended-release buprenorphine (equivalent to 16 mg/d) or sublingual buprenorphine, which included either self-administration instructions if the COWS score was less than 8 or administration of 8 mg of sublingual buprenorphine in the ED if the COWS score was 8 or higher. All sublingual buprenorphine group patients received a 7-day prescription for 16 mg/d. Both groups were provided referral for ongoing medication with a scheduled appointment within 7 days. Main Outcomes and Measures Engagement in opioid use disorder treatment on day 7 was the primary outcome. Secondary outcomes included engagement at 30 days, precipitated withdrawal and overdose events, craving scores, days of illicit opioid use, and patient satisfaction with treatment. Results Among 2000 patients randomized, 6 who were enrolled twice were excluded, resulting in 991 in the extended-release group and 1003 in the sublingual group. The median age was 37 (IQR, 30-47) years, 68% were male, 31% had an initial COWS score of 4 to 7, and 76% tested positive for fentanyl. The adjusted proportion of engagement in opioid use disorder treatment at 7 days was 40.5% with extended-release buprenorphine vs 38.5% with sublingual buprenorphine (adjusted difference, 1.6%; 95% CI, −2.8% to 6.0%). Engagement at 30 days was similar, with adjusted proportions of 43.8% with extended-release buprenorphine vs 44.9% with sublingual buprenorphine (adjusted difference, −1.5%; 95% CI, −6.2% to 3.2%). Precipitated withdrawal was rare: 6 (0.6%) with extended-release buprenorphine and 8 (0.8%) with sublingual buprenorphine. Overdose events within 30 days occurred in 18 participants (2.3%) in each group. Patients receiving extended-release buprenorphine reported lower mean craving scores at 7 days vs those receiving sublingual buprenorphine (scale, 0-100; mean score, 26.5 vs 30.2, respectively; adjusted mean difference, −3.85; 95% CI, −7.08 to −0.63), fewer days of illicit opioid use in the past 7 days (adjusted ratio of means, 0.77; 95% CI, 0.68-0.95), and better treatment satisfaction scores (scale, 1-5; adjusted mean difference, 0.13; 95% CI, 0.01-0.25). Conclusions and Relevance No difference was detected in opioid use disorder treatment engagement on day 7 between the 7-day extended-release and sublingual buprenorphine groups. Both buprenorphine formulations were well tolerated; precipitated withdrawal was rare despite a high prevalence of fentanyl. Trial Registration ClinicalTrials.gov Identifier: NCT04225598
D'Onofrio et al. (Wed,) studied this question.