Naltrexone implants after in-patient treatment for opioid dependence: randomised controlled trial.

Background: Naltrexone has considerable potential in helping to prevent relapse in heroin dependency. A longer-lasting formulation for naltrexone treatment is desirable to further reduce non-adherence and relapse during treatment of opiate dependence.
Aims: To evaluate the safety and effectiveness of a 6-month naltrexone implant in reducing opioid use after in-patient treatment.
Method: A group of 56 abstinence-oriented patients who completed in-patient treatment for opioid dependence were randomly and openly assigned to receive either a 6-month naltrexone implant or their usual aftercare. Drug use and other outcomes were assessed at 6-month follow-up.
Results: Patients receiving naltrexone had on average 45 days less heroin use and 60 days less opioid use than controls in the 180-day period (both P<0.05). Blood tests showed naltrexone levels above 1 ng/ml for the duration of 6 months. Two patients died, neither of whom had received an implant.
Conclusions: Naltrexone implant treatment safely and significantly reduces opioid use in a motivated population of patients.