Surmounting Withdrawal to Initiate Fast Treatment With Naltrexone

Inclusion Criteria

• 18 years of age or older.
• Meets current Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria for opioid use disorder.
• Seeking treatment for opioid use disorder, willing to accept treatment with XR- NTX and, in the judgment of the treating physician, is a good candidate for naltrexone- based treatment.
• Willing and able to provide written informed consent.
• Able to speak English sufficiently to understand the study procedures and provide written informed consent to participate in the study.
• If female of childbearing potential, willing to practice an effective method of birth control for the duration of participation in the study.

Exclusion Criteria

• Serious medical, psychiatric or substance use disorder that, in the opinion of the study physician, would make a detoxification and naltrexone initiation, or maintenance treatment with XR-NTX, hazardous (relative contra-indications) or requires a different level of care. Examples include:
• Disabling or terminal medical illness (e.g., uncompensated heart failure, severe acute hepatitis, cirrhosis or end-stage liver disease) as assessed by medical history and/or review of systems.
• Severe, untreated or inadequately treated mental disorder (e.g., active psychosis, uncontrolled manic-depressive illness) as assessed by history and/or clinical interview.
• Current severe alcohol, benzodiazepine, or other depressant or sedative hypnotic use likely to require a complicated medical detoxification (routine alcohol and sedative detoxifications may be included).
• Suicidal or homicidal ideation that requires immediate attention. Known allergy or sensitivity to buprenorphine, naloxone, naltrexone, polylactide-co-glycolide, carboxymethylcellulose, or other components of the Vivitrol® diluent.
• Maintenance treatment with methadone. 4. Maintenance treatment with buprenorphine unless the patient is determined to have a poor treatment response (in the form of buprenorphine non-adherence with or without the use of illicit opioids), warranting change to XR-NTX treatment.
• Presence of pain of sufficient severity as to require ongoing pain management with opioids.
• Circumstances (legal, personal, occupational) that would threaten the feasibility of XR- NTX treatment or make another treatment (e.g. buprenorphine or methadone) a better choice.
• Are currently in jail, prison or other overnight facility as required by court of law or have pending legal action that could prevent participation in study activities.
• If female, currently pregnant or breastfeeding, or planning on conception. 9. Body habitus that, in the judgment of the study physician, precludes safe intramuscular injection of XR-NTX (e.g., BMI>40, excess fat tissue over the buttocks, emaciation).
• Admitted to the inpatient detoxification or residential rehabilitation unit more than 3 days prior to consent.