Adapting treatment length to opioid‐dependent individuals’ needs and preferences: a 2‐year follow‐up to a 1‐year study of extended‐release naltrexone

BACKGROUND AND AIMS: Extended‐release naltrexone (XR‐NTX) is an under‐used treatment option for opioid dependence, today only available in a few countries in the world. Although effective, safe and feasible in short‐term treatment, long‐term data are scarce and there is no recommendation for required treatment length. The aims of the study were to determine the perceived need of long‐term XR‐NTX treatment and to examine long‐term treatment outcomes. DESIGN: In this prospective cohort study, following a parent 1‐year study of XR‐NTX, participants received treatment with XR‐NTX at their own discretion for a maximum of 104 weeks. SETTING AND PARTICIPANTS: Five urban, outpatient addiction clinics in Norway, comprising opioid‐dependent adults aged 18–60 years (n = 50) already participating in the parent study. INTERVENTION: XR‐NTX administered as intramuscular injections (380 mg) every 4 weeks. MEASUREMENTS: Time in the study, use of opioids and other illicit substances, opioid craving and treatment satisfaction reported every 4 weeks. FINDINGS: Among 58 participants who completed the 1‐year parent study, 50 chose to continue the treatment with XR‐NTX. Median prolonged treatment time was 44.0 weeks [95% confidence interval (CI) = 25.5–62.5], ranging from 8 to 104 weeks. Most participants (35, 70%) reported no relapse to opioid use during treatment while a subgroup (15, 30%) reported relapses to opioids during the study. Scores for mean treatment satisfaction and recommending treatment to others were very high (>9) and mean opioid craving score was very low (<1) on a scale ranging from 0 to 10. CONCLUSIONS: Extended‐release naltrexone (XR‐NTX) was well tolerated in long‐term treatment of opioid‐dependent individuals in Norway already in XR‐NTX treatment. On average, the participants chose to continue treatment for almost 1 year beyond the initial 9–12 months of treatment. Participants reported high treatment satisfaction and 70% showed no relapse to opioids during the treatment period.