Extended-release Buprenorphine as a Novel Low-dose Induction Strategy

This is a clinical trial to characterize the safety and pharmacokinetics of using extended-release buprenorphine (XR-BUP) as a novel low-dose buprenorphine induction strategy. Individuals with a diagnosis of Opioid Use Disorder (OUD) (n=30) will be admitted to an inpatient unit to complete study procedures over the course of 3 days. Participants will receive fentanyl to prevent the emergence of withdrawal. Each participant will then receive a single injection of XR-BUP after which study staff will monitor for any precipitated withdrawal.

Inclusion Criteria: * English speaking adults aged 18 and above. * diagnosis of opioid use disorder. * Self-reporting use of illicit opioids in \>21 days in the prior 30 days. * Provide urine toxicology testing positive for fentanyl at baseline. Exclusion Criteria: * Seeking medication treatment for opioid use disorder with sublingual buprenorphine or methadone. * Received buprenorphine or methadone treatment in prior 30 days. * Current diagnosis of alcohol or sedative/hypnotic use disorder. * Positive urine drug screen for benzodiazepines, alcohol and or methadone. * Physical dependence on alcohol or sedative/hypnotics. * Psychotic disorder, active suicidality or homicidally or any psychiatric condition that impair ability to provide informed consent. * Have a history or diagnosis of Intracranial mass/bleed, seizure disorder, liver cirrhosis, renal failure, obstructive lung disease, hyperthyroidism, narrow-angle glaucoma, valvular heart disease, cardiac arrhythmias, heart failure. * Recent (within 6 months) head trauma, stroke, or myocardial infarction * Requiring treatment with opioids for acute or chronic pain. * History of hypersensitivity or allergy to buprenorphine or fentanyl. * Pregnant or breastfeeding. * Liver function test greater than 3 times upper normal limit. * Receiving medications that are strong or moderate CYP34A inducers or inhibitors (including but not limited to ketoconazole, itraconazole, clarithromycin, fluconazole, erythromycin), in the past 30 days.