Naltrexone Does Not Increase Pain Among Individuals With OUD and Mild–moderate Chronic Pain

Chronic pain is common, especially among individuals with opioid use disorder (OUD). There is increasing evidence that opioids often provide little benefit for treatment of chronic pain, but less is known about the effect of opioid antagonists on chronic pain. Researchers used data from a randomized-controlled trial comparing sublingual buprenorphine (BUP) and extended-release naltrexone (XR-NTX) for treatment of DSM-IV opioid dependence. The trial had two phases: a 12-week randomized phase followed by a 36-week open-treatment phase with the patient’s treatment of choice. Participants were assessed for pain every 4 weeks. Chronic pain was not an exclusion criterion, but individuals with severe chronic pain were not encouraged to participate.

• Of 232 individuals assessed for eligibility, 159 were randomized to treatment with BUP or XR-NTX; 143 received at least one dose of medication and attended at least one assessment. During the open-treatment phase, 117 of 122 participants chose to receive XR-NTX.
• At week 4, 81 participants reported chronic pain and 55 reported no pain.
• During the 12-week randomized phase, the number of individuals reporting no pain slightly increased; mean pain scores did not significantly change. Assessed pain did not significantly differ between treatment groups.
• During the 36-week open-treatment phase, there was no significant change in assessed pain and those who switched from BUP to XR-NTX did not report an increase in pain.

Comments: Among individuals with OUD who volunteered for a study of XR-NTX and did not have severe chronic pain, initiation of XR-NTX did not result in increased pain. This suggests that XR-NTX is a reasonable option for those with mild–moderate chronic pain and raises further questions about the efficacy of opioid agonists for the treatment of chronic pain.

Darius A. Rastegar, MD

Reference: Latif ZH, Solli KK, Opheim A, et al. No increased pain among opioid‐dependent individuals treated with extended‐release naltrexone or buprenorphine‐naloxone: A 3‐month randomized study and 9‐month open‐treatment follow‐up study. Am J Addict. 2019;28:77–85.