In recent years, both abstinence- and harm-reduction strategies for managing opium dependency are being generalized. In those who use detoxification, maintenance therapy with Naltrexone, an opioid antagonist protects them against relapse. This is important to know the best time of Naltrexone discontinuation to lower the risk of relapse.

This study tried to determine the efficacy of Naltrexone in prevention of opioid relapse and the factors interfere to the outcome.

150 opium addicts who were admitted in Kermanshah Rehabilitation Centre for Naltrexone maintenance therapy contributed in this 18 month length study. They received Naltrexone for 6 months and followed then after for another 12 months. Opium test (TLC) were done monthly in the first 6 months, and then in 3 month intervals for 12 subsequent months to find out the relapse.

1. 1) The relapse rates were 56.7%(85) after 6-month, and 4.7%(7)after one-year.

2. 2) The succession rate was 38.6%(58).

3. 3) The lowest succession rate was in 18–25 year old, The highest was in 35–40 year old adults(10).

4. 4) In person with diploma and higher the succession rate(43.8%) was higher than poor educated(34.7%) ones.

5. 5) The succession rate was higher in those who: were employee(72.7%), were addicted to heroin(44.9%), didn’t have positive family history(41.3%), and had more incomes(46.7%).

1. 1) In those who the relapse is delayed until 9 months after detoxification, the chance of long term abstinence is higher.

2. 2) The employees and those who have more social disciplines are more successful in ceasing opium abuse.