Supplementary Material for: Interest in Extended Release Naltrexone among Opioid Users

<i>Background/Aims:</i> Treatment for addiction to illicit opioids has, thus far, been limited to 2 main approaches: maintaining physical dependence by administering opioids medically and medication-free abstinence with psychosocial support. Assisted abstinence by taking daily tablets with the opioid antagonist naltrexone is rarely practiced, but it is unclear whether this is due to the limited efficacy of this method or because of user opposition to antagonist medication. Therefore, we wanted to investigate opioid users' interest in antagonist treatment with naltrexone, administered as extended release injection, which supports abstinence by blocking illicit opioids for 4-5 weeks per administration. <i>Method:</i> A one-page questionnaire was distributed among opiate users at a broad range of outreach facilities and a total of 731 answered surveys were analysed. <i>Results:</i> More than half of the opioid users in our study were ‘very' or ‘quite' interested in receiving a 4-weekly opioid-blocking medication for a year (n = 421), while less than a quarter (n = 164) were ‘not interested' at all. <i>Conclusion:</i> We discovered a high user interest for naltrexone treatment, suggesting that the interest for such treatment was not a barrier to the implementation of extended release naltrexone treatment.