Oral naltrexone maintenance treatment for opioid dependence

Minozzi S, Amato L, Vecchi S, Davoli M, Kirchmayer U, Verster A

Summary

Oral naltrexone maintenance treatment for opioid dependence

Methadone treatment is widely used for detoxification or long-term maintenance therapy of opioid users to reduce harm and improve health and social outcomes yet relapses to illicit drug use are common. Naltrexone is an opioid antagonist that has no euphoric effects and could provide a non-addicting treatment for opioid users yet retention rates in treatment are low, making its effectiveness questionable. People such as health professionals, business executives and those who are under probation in the legal system have strong incentives to complete treatment and may be good candidates for naltrexone treatment. Sustained release preparations that reduce the frequency of dosing may make naltrexone treatment more effective.
The results of this review show that naltrexone maintenance therapy, alone or in association with psychosocial therapy, was more effective than non-active placebo, alone or with psychosocial therapy, in limiting the use of heroin during treatment. Where naltrexone was compared with non-active placebo, the difference did not reach statistical significance. No clear benefit was shown in terms of retention in treatment, side effects or relapse at follow up. This conclusion is based on 10 controlled studies that randomised 696 participants to naltrexone alone or with psychosocial therapy compared with psychosocial therapy alone or placebo. Participants were opiate addicts after detoxification and were predominantly male with the mean age ranging from 22 and 39 years. Two of the studies (89 participants) evaluated the effectiveness of naltrexone in parolees or probationers. Naltrexone combined with psychosocial therapy was more effective than psychosocial treatment alone for the number of participants re-incarcerated during the study period. The mean length of the trial was six months (range 1 to 10 months). The studies were from diverse countries and used varying dose schedules for naltrexone.