Factors associated with receipt of second injection of naltrexone for opioid use disorder: Secondary analysis of 5 clinical trials.

Abstract

Background and objectives: Extended-release injectable naltrexone (XR-naltrexone) is an effective relapse prevention treatment of patients with opioid use disorder (OUD), but retention remains a problem. Previous trials have either only calculated the association of one or two predictors or used claims-based datasets with only limited data to identify these characteristics. This analysis tested multiple baseline and clinical predictors for association with early retention on XR-naltrexone using combined data from five consecutive studies enrolling patients with active opioid use.

Methods: Bivariate associations between patients' demographic and clinical characteristics at baseline and during the weeks after the first XR-naltrexone injection, and receipt of a second injection were calculated (n = 200). Significant factors were included in a multivariable logistic regression model.

Results: 148/200 participants (74%) received the second injection. Lower Hamilton-Depression Scale (HAM-D) scores after the first injection were significantly associated with receiving a second injection in univariate and multivariable analysis. The following factors were significantly associated with receipt of the second injection in the univariate but not in the multivariable model: longest period of abstinence 1-11 months, use of cocaine in the 7 days before enrollment, use of alcohol or cocaine in the week after first injection, lower severity of cravings for opioids after first injection, lower self-report withdrawal scores after the first injection.

Conclusions and scientific significance: Depressive symptoms after first XR-naltrexone injection are associated with nonreceipt of a second injection. Clinicians should educate patients about this risk and monitor for possible depression symptoms after the first injection.