Patterns of withdrawal in patients with opioid use disorder (OUD) transitioning from untreated OUD or buprenorphine treatment to extended-release naltrexone.

BACKGROUND Pharmacologic treatment is recommended for many individuals with opioid use disorder (OUD). For patients who select opioid antagonist treatment, effective management of opioid withdrawal symptoms during transition to antagonist treatment requires consideration of the patient experience. OBJECTIVES To compare patterns of opioid withdrawal between those withdrawing from untreated opioid use and those withdrawing from buprenorphine. METHODS We performed a post hoc, cross-study comparison of the temporal pattern of opioid withdrawal during 1-week induction onto extended-release naltrexone by similar protocols enrolling two participant populations: participants with OUD entering a study with untreated opioid use (N = 378, NCT02537574) or on stable buprenorphine (BUP) treatment (N = 101, NCT02696434). RESULTS The temporal pattern of withdrawal from induction day 1 through day 7 differed between the two participant populations for Clinical Opiate Withdrawal Score (COWS) and Subjective Opiate Withdrawal Score (SOWS): participants with untreated OUD prior to study entry were more likely to experience an earlier relative peak in opioid withdrawal followed by a gradual decline, whereas participants on stable BUP treatment prior to study entry were more likely to experience a relatively later, though still mild, peak opioid withdrawal. The peak COWS was reached at a mean (standard deviation) of 1.9 (1.5) days for participants with untreated OUD and 5.0 (1.5) days for participants on stable BUP. Daily peak cravings were generally higher for participants with untreated OUD than participants on stable BUP. CONCLUSION Awareness of population-specific variations in the patient experience of opioid withdrawal may help clinicians anticipate the expected course of withdrawal.