Pre-Release VIVITROL for Opioid Dependent Inmates

Inclusion Criteria:

1. Incarcerated adults with known release date.
2. Meet DSM-IV criteria for current (and/or prior to incarceration) opioid dependence.
3. Not interested in agonist (methadone, buprenorphine) treatment.
4. Currently opioid free by history ('detoxed'), with negative urine for all opioids and no sign of opiate withdrawal after IV (or IM if no available venous access) injection of 0.8 mg naloxone.
5. Good health by medical history, physical examination and laboratory tests.
6. Age older than 18.
7. Understands and signs a consent form.
8. Able to speak and understand English.
9. Females: not pregnant (urine hCG negative at baseline and prior to each injection), not planning conception; and planning appropriate contraception if sexually active.

Exclusion Criteria:

1. Current drug or alcohol dependence requiring long term residential treatment that would interfere with outpatient study participation. Dependence on substances that commonly co-occur with opioid dependence (e.g. cocaine, cannabis, alcohol) that do not rise to this level of severity will not be exclusionary in order to achieve a maximally representative sample.
2. Liver failure and/or liver function test levels greater than three times normal.
3. Pregnancy, lactation, or failure to use adequate contraceptive methods;
4. Active medical illness that might make participation hazardous, e.g. untreated hypertension, hepatitis with AST or ALT > 3 times upper limit of normal, unstable diabetes or heart disease. Adequately treated medical conditions are acceptable.
5. Untreated psychiatric disorder that might make participation hazardous, e.g. untreated psychosis, bipolar disorder with mania, significant suicide risk. Adequately treated psychiatric disorders and appropriate psychotropic medications would be allowed.
6. History of allergic reaction to naltrexone;
7. Current chronic pain diagnosis for which opioids are required for pain relief.
8. Obesity (BMI of 40 or greater) to reduce the likelihood of injection site reaction.
9. Known intolerance and/or hypersensitivity to naltrexone, carboxymethylcellulose, or polylactide-co-polymers (PLG) or any other components of the diluents.