Pathways to 7-day Extended-release Buprenorphine (CAM2038) Administration in Emergency Department and Hospitalized Patients

Objectives: To describe the clinical contexts, population characteristics, and outcomes of extended-release buprenorphine (CAM2038 7-day depot formulation) administration in emergency department and hospitalized patients with opioid use disorder primarily using fentanyl. Methods: We conducted a retrospective case series of patients who received CAM2038 at an urban safety-net hospital between June 2024 and June 2025. We collected data from electronic health records, including demographics, clinical characteristics, and outcomes. Outcomes included opioid withdrawal severity, buprenorphine-precipitated withdrawal, patient-directed discharge, and 30-day linkage to care within our health care system. Results: Thirty-seven patients received CAM2038, with 33 utilizing CAM2038 to initiate buprenorphine and 4 transitioning from another formulation of therapeutic buprenorphine. Most patients (91.9%) primarily used fentanyl. Among patients using CAM2038 to initiate buprenorphine, 25 patients (75.8%) received pretreatment of opioid withdrawal with short-acting full agonist opioids. Two patients (6%) had suspected precipitated withdrawal. Among patients with documented Clinical Opiate Withdrawal Scale scores post-injection (n=24), 91.7% experienced minimal-to-mild withdrawal (score <12). Patient-directed discharge was uncommon (10.8%), and 47% of patients linked to buprenorphine treatment within 30 days. Conclusions: CAM2038 administration, including for the initiation of therapeutic buprenorphine, seems to be feasible and well-tolerated in inpatient and emergency department settings, with low rates of precipitated withdrawal and patient-directed discharge. The use of short-acting opioids for initial withdrawal management may contribute to successful outcomes. These findings support CAM2038 as a valuable option for treating opioid use disorder in the emergency department and hospital settings, particularly among patients who use fentanyl.