Extended Release Naltrexone Versus Extended Release Buprenorphine With Individuals Leaving Jail

Inclusion Criteria: * Adult male or female inmates at participating jails who are eligible for release within 120 days * History of opioid use disorder (meeting DSM-5 criteria of moderate or severe opioid use disorder at the time of incarceration; individuals not meeting the opioid-disorder criterion will be eligible if they were treated in an opioid agonist treatment program during the year before incarceration) * Suitability for XR-B and/or XR-NTX treatment as determined by medical evaluation * Willingness to enroll in XR-B or XR-NTX treatment in jail * Planning to live in one of the 7 participating counties and/or surrounding counties Exclusion Criteria: * Liver function test levels greater than 4 times normal; * Active medical illness that may make participation hazardous (e.g., unstable diabetes, heart disease; moderate to severe renal impairment; adequately treated medical conditions are acceptable); * Conditions or medications that may predispose to QTc prolongation (personal or family history of long QT syndrome, hypokalemia, medications that prolong QTc interval, e.g., macrolide antibiotics, azole antifungal compounds, anti-arrythmics, antipsychotics and antidepressant) * Untreated psychiatric disorder that may make participation hazardous (e.g., untreated psychosis, bipolar disorder with mania; adequately treated psychiatric disorders and appropriate psychotropic medications will be allowed); * History of allergic reaction to naltrexone and/or buprenorphine; * Cu…