Eligibility Details:  
        Inclusion Criteria:
          1. Individuals between the ages of 18-60
          2. Meets DSM-5 criteria of current opioid use disorder with six consecutive months of
             reported heroin use, supported by a positive urine for opiates indicating regular use
             of heroin
          3. Seeking treatment for opioid use disorder with Vivitrol
          4. Capable of giving informed consent and complying with study procedures
          5. In otherwise good health based on complete medical history and physical examination,
             laboratory tests, and EKG
          6. BMI between 18-40
        Exclusion Criteria:
          1. Reported treatment with methadone in the last 3 months or positive urine toxicology
             for methadone on the day of consent
          2. Maintenance on, or regular use of buprenorphine or other prescription opioids
          3. Pregnancy, lactation, or failure in a sexually active woman to use adequate
             contraceptive methods.
          4. Active medical illness which might make participation hazardous, such as untreated
             hypertension, acute hepatitis with AST or ALT > 3 times normal, AIDS (CD4 count under
             200 currently or medically ill with an opportunistic infection), unstable diabetes,
             cardiovascular disease.
          5. Active psychiatric disorder which might interfere with participation or make
             participation hazardous, including DSM-5 Schizophrenia or any psychotic disorder,
             severe Major Depressive Disorder, or suicide risk or 1 or more suicide attempts within
             the past year.
          6. Physiologically dependent on alcohol or sedative- hypnotics with impending withdrawal.
             Other substance use diagnoses are not exclusionary.
          7. History of allergic or adverse reaction to buprenorphine, naltrexone, naloxone,
             clonidine, or clonazepam.
          8. Chronic neurocognitive disorder
          9. History of accidental drug overdose in the last 3 years as defined as an episode of
             opioid-induced unconsciousness or incapacitation, whether or not medical treatment was
             sought or received.
         10. Painful medical condition that requires ongoing opioid analgesia or anticipated
             surgery necessitating opioid medications
         11. Fentanyl only use, supported by a urine toxicology that is positive for fentanyl only
             and negative for all other opioids.
         12. Court mandated to treatment