Pain intensity in patients using extended-release naltrexone or opioid agonists and its effect on extended-release naltrexone treatment outcomes.

Abstract

Background and objectives: Extended-release naltrexone (XR-NTX) is an opioid antagonist effective for treating opioid use disorder (OUD). However, concerns about inadequate pain management may limit its use. This study will examine changes in pain intensity in OUD patients choosing XR-NTX compared to opioid agonist treatment (OAT), identify subgroups with distinct pain intensity trajectories, and assess the effect of pain intensity on XR-NTX treatment outcomes (retention, relapse, opioid use, and cravings).

Methods: This 24-week study included OUD patients aged 18-65 years opting for XR-NTX (n = 160). Patients receiving OAT (n = 151) served as controls. Pain intensity was measured every 4 weeks for XR-NTX and at baseline and Week 24 for OAT using the numerical pain rating scale-11 (NPRS-11). Data were analyzed with linear mixed models and group-based trajectory modeling.

Results: Between baseline and Week 24, XR-NTX participants with low to moderate pain showed a significant reduction in pain intensity, while those with high pain did not. In the OAT group, no significant reduction in pain intensity was observed (from baseline to Week 24). Pain intensity was not associated with XR-NTX treatment outcomes.

Discussion and conclusions: Contrary to perception, XR-NTX does not worsen pain intensity, nor did pain intensity affect XR-NTX treatment outcomes.

Scientific significance: This study is the first to explore the association between changes in pain intensity and XR-NTX treatment outcomes in OUD patients over a 24-week period. The findings challenge the perception that XR-NTX is less suitable for treating OUD patients with pain.