Naltrexone for Use in Conjunction With Buprenorphine in Adults With Opioid Use Disorder Prior to First Dose of VIVITROL® (Naltrexone for Extended-Release Injectable Suspension)

Inclusion Criteria: * Willing and able to provide informed consent * Willing and able to provide government-issued identification * Has a BMI of 18.0-40.0 kg/m\^2 * Has a physiologic dependence on opioids * Is voluntarily seeking treatment for opioid use disorder and willing to completely withdraw from his/her opioid use throughout the study with desire for or motivation for antagonist therapy * Wiling to abide by the contraception requirements for the duration of the study * Additional criteria may apply Exclusion Criteria: * Is pregnant, planning to become pregnant or breastfeeding during the study * Has used Buprenorphine within 7 days prior to randomization * Has used Methadone within 14 days prior to randomization * Has a history of VIVITROL use within 90 days prior to screening or has used oral naltrexone within 14 days prior to randomization * Has a history of seizures or has received anticonvulsant therapy within the past 5 years * Has a condition, disease state, or previous medical history that would preclude safe participation in the study or affect the ability to adhere to the protocol visit schedule, requirements, or assessments * Has a current diagnosis of schizoaffective disorder, bipolar disorder, or untreated and unstable major depressive disorder * Is currently physiologically dependent on any psychoactive substance (except opioids, caffeine, or nicotine) requiring medical intervention for detoxification * Has a history of hypersensitivity or adverse react…