Among Individuals With Opioid Use Disorder, Initiation of Extended-release Naltrexone Did Not Increase Pain Intensity

Individuals with opioid use disorder (OUD) have high rates of chronic pain. The efficacy of opioid agonist medications for chronic pain is questionable at best, and previous studies found that individuals with chronic pain who start extended-release naltrexone (XR-NTX) do not report increased pain. This study was a secondary analysis of an observational study in Norway comparing individuals with OUD who chose to start XR-NTX and those who were prescribed opioid agonist therapy (OAT). The goal was to see if initiation of XR-NTX had an effect on pain intensity, and whether pain intensity had an effect on treatment outcomes at six months.

• There were 160 participants receiving XR-NTX who completed at least one pain questionnaire; 79 (49 percent) completed six-month follow-up. There were 151 patients receiving OAT; 122 (81 percent) completed six-month follow-up.
• In the XR-NTX group, there was a significant reduction in pain intensity from baseline to follow-up among patients with low and low-to-moderate pain, but not among patients with high levels of pain. In the OAT group, the reduction in pain intensity was not significant.
• In the XR-NTX group, there was no significant association between baseline pain intensity and treatment retention.

Comments: This study adds to growing evidence that opioid agonist medications are not an effective treatment for chronic pain. While treatment retention was better among patients receiving OAT compared with XR-NTX, this study suggests that chronic pain should not be a reason to choose OAT over XR-NTX.

Darius A. Rastegar, MD

Reference: Juya F, Solli KK, Holtan L, et al. Pain intensity in patients using extended-release naltrexone or opioid agonists and its effect on extended-release naltrexone treatment outcomes. Am J Addict. 2025;34(5):528–535.