no funding available to continue

The study will enroll 30 opioid-dependent participants into an open-label pilot outpatient study of methods to facilitate induction and stabilization onto XR-NTX. There will be three different methods of XR-NTX induction using increasing doses of oral naltrexone and buprenophine.

Procedure 1: 5-day induction with increasing doses of oral naltrexone. Participants will receive XR-NTX on day five together with buprenorphine, and will continue receiving buprenorphine for 4 weeks until they receive 2nd XR-NTX dose.

Procedure 2: 10-day induction with buprenorphine administered daily and increasing daily doses of oral naltrexone beginning on day 2 . On day 10 participants will receive XR-NTX dose, and another one 4 weeks later. No buprenorphine will be given beyond day 10.

Procedure 3: 10-day induction with buprenorphine administered daily and increasing daily doses of oral naltrexone beginning on day 2 . On day 10 participants will receive XR-NTX dose, and another one 4 weeks later. Buprenorphine will continue for 4 weeks until the 2nd XR-NTX dose.

All participants will receive weekly therapy with a study psychiatrist. All participants will receive open-label medication.

Inclusion Criteria:

1. Age 18-60.
2. Meets DSM-5 criteria for current opioid use disorder (moderate-severe) of at least six months duration, supported by urine toxicology OR COWS score > or =6 OR Naloxone Challenge.
3. Voluntarily seeking treatment for opioid dependence.
4. In otherwise good health based on complete medical history and physical examination within normal ranges (AST or ALT < 3 times normal). )
5. Able to give written informed consent.

Exclusion Criteria:

1. Methadone maintenance treatment or regular use of illicit methadone (> 30 mg per week).
2. Maintenance on, or regular use of buprenorphine or other long-acting narcotic agonists.
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.
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 organic mental disorder (e.g. AIDS (CD4 count under 200 currently or medically ill with an opportunistic infection) dementia).
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.

8 weeks

AE data were collected over the period of study participation, which is 8 weeks for each participant