EXHIT ENTRE Comparative Effectiveness Trial

Inclusion Criteria: 1. Hospitalized. 2. At least 18 years of age. 3. Meet Diagnostic and Statistical Manual (DSM-5) criteria for moderate or severe OUD. 4. Willing to initiate MOUD, including buprenorphine. 5. Able to speak English sufficiently to understand the study procedures and provide written informed consent to participate in the study. Exclusion Criteria: 1. Anticipated length of stay less than 24-hours as determined by the ACS 2. Affected by a serious medical, psychiatric, or substance use disorder that, in the opinion of the study physician, would make it unsafe to participate in the study or may prevent collection of study data. This may include: 1. Disabling terminal diagnosis for which discharge from hospital is not anticipated. 2. Disabling terminal diagnosis for which hospice care is being sought. 3. Severe alcohol or benzodiazepine use disorder that is anticipated to require complex medical detoxification which cannot be completed prior to randomization. 3. Taking a long-acting opioid other than buprenorphine (e.g., methadone, extended-release oxycodone, extended-release morphine) in the three consecutive days prior to randomization. 4. Liver enzyme tests (Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT)) more than 5 times upper limit of normal or chronic decompensated liver disease. 5. Currently pregnant. 6. Known allergy to buprenorphine or components of Atrigel delivery system. 7. Receipt of MOUD in the 14 days prior to hospitalization as maintenance treatment; however, patients may have received MOUD for withdrawal management during or prior to hospitalization at the time of enrollment. 8. Are currently in jail, prison or other overnight facility as required by court of law and/or is considered a prisoner under local law or is under current terms of civil commitment or guardianship. 9. Previously randomized as a participant in the study - individuals may only be enrolled and randomized once.