This is an open-label pilot trial to evaluate the safety and tolerability of lofexidine in the management of opioid withdrawal symptoms while initiating outpatient treatment with naltrexone. The initiation procedure will be a flexible detoxification lasting 2 to 10 days concluding with the injection of XR-Naltrexone (Vivitrol). Vivitrol is a long-acting injection that contains enough medicine to last for one month blocking the effects of opioids.

This is an open-label pilot trial to evaluate the safety and tolerability of lofexidine in the management of opioid withdrawal symptoms while initiating outpatient treatment with naltrexone. Lofexidine is a nonopioid prescription medicine used in adults to help with the symptoms of opioid withdrawal that may happen when a person stops taking an opioid suddenly. The initiation procedure will be a flexible detoxification lasting 2 to 10 days concluding with the injection of XR-Naltrexone (Vivitrol). Vivitrol is a long-acting injection that contains enough medicine to last for one month blocking the effects of opioids. Lofexidine will be fixed-flexible dosing started on day 1 with maximum dose being three 0.18mg tablets taken orally 4 times daily at 4-to 6-hour intervals. Lofexidine treatment will continue throughout the detoxification, up to 10 days, and will be discontinued with a gradual dose reduction over 2 to 4 days. Precipitated withdrawal symptoms are treated with lofexidine, clonazepam, and other comfort medications. After the induction patients will be seen at the clinic for 8 weeks. Twice weekly for the first month and weekly for weeks 5-8. A second Vivitrol injection will be provided at week 4.

Inclusion Criteria:

• Individuals between the ages of 18-60
• Meets DSM-5 criteria of current opioid use disorder present for at least six months, supported by a positive urine for opioids on day of consent
• Seeking treatment for opioid use disorder
• Capable of giving informed consent and complying with study procedures
• History of opioid withdrawal

Exclusion Criteria:

• Meets DSM-5 criteria for substance use disorder other than opioid as the primary diagnosis
• Having a comorbid psychiatric diagnosis that might interfere with participation or make participation hazardous, such as an active psychotic disorder or current suicide risk
• Methadone maintenance or long-acting agonist (buprenorphine) treatment -Buprenorphine maintenance treatment
• Known history of allergy, intolerance, or hypersensitivity to candidate medication
• Pregnancy, lactation, or failure to use adequate contraceptive methods in female patients
• Unstable medical conditions, which might make participation hazardous such as uncontrolled hypertension (blood pressure >150/100), acute hepatitis, uncontrolled diabetes, or elevated liver function tests (AST and ALT >3 times the upper limit of normal)
• Legally mandated to substance use disorder treatment
• Currently physiological dependence on alcohol or sedative-hypnotics that would require a medically supervised detoxification-other substance use diagnoses are not exclusionary
• Painful medical condition that requires ongoing opioid analgesia or anticipated surgery necessitating opioid medications (Clinical interview; psychiatrist)

There is not a plan to make IPD available.

2-10 day induction period followed by 8 weeks of the trial