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Background and Aims: Extended-release formulations of naltrexone have emerged as effective treatment options for opioid use disorder. This post-hoc analysis examined the temporal relationship between episodes of opioid use and subsequent dropout in a placebo-controlled trial of extended-release injection naltrexone (XR-NTX) to draw inferences about the mechanism by which extended blockade of opioid receptors translates into clinical effectiveness., Design: This was a 24-week multiple-site, double-blind, randomized trial of monthly XR-NTX versus placebo injections. We analyzed time to dropout from treatment using survival analysis with an extended Cox model as a function of treatment (XR-NTX versus placebo) and with weekly urine drug test (UDT) results for opioids at each week as a time-dependent covariate., Setting: Thirteen addiction treatment programs in Russia, 2008-09., Participants: A total of 250 adults with opioid use disorder who had completed in-patient detoxification., Intervention: XR-NTX injection or placebo injection every 4 weeks with weekly clinic visits and biweekly counseling., Measurements: Urine toxicology for opioids measured weekly and week of dropout from treatment., Findings: The Cox model yielded a significant interaction of time-dependent urine toxicology by treatment (P = 0.024). Among patients receiving placebo, a positive UDT in a given week increased the risk for dropout from treatment in the subsequent week [hazard ratio (HR) = 6.25; 95% confidence interval (CI) = 3.6-10.0], whereas among patients receiving XR-NTX, a positive UDT result showed no significant effect on risk for dropout (HR = 1.67; 95% CI = 0.6-4.5). The proportion of patients who completed all 24 weeks without any positive UDT result was 31% on XR-NTX compared with 20% on placebo (P = 0.051)., Conclusions: Extended-release injection naltrexone was effective at reducing the risk of dropout from opioid use disorder treatment after an episode of opioid use. Just under a third of patients (31%) on XR-NTX had no opioid-positive urine tests across the trial, but the hypothesis that this would differ from placebo (20%) was not confirmed., (© 2019 Society for the Study of Addiction.)

Background and Aims: Extended-release naltrexone (XR-NTX), a μ-opioid receptor antagonist for prevention of relapse to opioid dependence, has demonstrated efficacy compared with placebo and comparative effectiveness with buprenorphine-naloxone. We report outcomes for XR-NTX in Vivitrol's Cost and Treatment Outcomes Registry., Design: Observational, open-label, single-arm, multi-center registry assessing baseline characteristics and clinical and health-related quality-of-life outcomes associated with XR-NTX treatment in clinical practice., Setting: 32 US treatment centers from 2011 to 2013., Participants: Patients with opioid dependence who were prescribed XR-NTX treatment and then enrolled into the registry., Measurements: Monthly visits were evaluated for the full population and for patient ubgroups retrospectively, defined by injection number, focusing on the period between baseline and month 6 (1-, 2/3- or 6-XR-NTX)., Findings: Of 403 enrolled patients, 395 were analyzed. Most patients (n = 349) received out-patient care. On average, patients received five injections (median = 3; range = 1-25). The median number of injections administered within 6 months was higher in patients who at baseline were employed (three versus two unemployed, P = 0.02) or had private insurance (five versus two self-payment, P = 0.005; versus two state-funded, P < 0.001). The 1-, 2/3- and 6-XR-NTX groups had 132, 152 and 111 patients, respectively. At baseline, the 6-XR-NTX patients were more likely to meet normal/minimal mental illness criteria and attend school and less likely to report recent drug use. Within 6 months, the 6-XR-NTX group demonstrated improvements in employment, mental health and psychosocial functioning, and decreases in opioid craving, drug use and drug-related behavior., Conclusions: Among opioid-dependent people receiving XR-NTX treatment, better mental health, higher education and lower recent drug use at baseline are associated with greater treatment duration; in turn, longer treatment duration is associated with lower relapse rates and improved outcomes generally., (Published 2018. This article is a U.S. Government work and is in the public domain in the USA.)