Slow release oral morphine versus methadone for opioid use disorder in the fentanyl era (pRESTO): Protocol for a non-inferiority randomized clinical trial.

backgroundNorth America is facing an unprecedented public health crisis of opioid-related morbidity and mortality, increasingly as a result of the introduction of illicitly manufactured fentanyl into the street drug market. Although the treatment of opioid use disorder (OUD) is a key element in the response to the opioid overdose epidemic, currently available pharmacotherapies (e.g., methadone, buprenorphine) may not be acceptable to or effective in all patients. Available evidence suggests that slow-release oral morphine (SROM) has similar efficacy rates as methadone with respect to promoting abstinence, and with improvements in a number of patient-reported outcomes among persons using heroin. However, little is known about the relative effectiveness and acceptability of SROM compared to methadone in the context of fentanyl use. This study aims to address this research gap.

methodspRESTO is a 24-week, open-label, two arm, non-inferiority, randomized controlled trial comparing SROM versus methadone for the treatment of OUD. Participants will be 298 clinically stable, non-pregnant adults with OUD, recruited from outpatient clinics in Vancouver, Canada, where the majority of the illicit opioids are contaminated with fentanyl. The primary outcome is suppression of illicit opioid use, measured by bi-weekly urine drug screens. Secondary outcomes include: treatment retention, medication safety, overdose events, treatment satisfaction, psychological functioning, changes in drug-related problems, changes in quality of life, opioid cravings, other substance use, and cost-effectiveness. DISCUSSION: pRESTO will be among the first studies to evaluate treatment options for individuals primarily using synthetic street opioids, providing important evidence to guide treatment strategies for this population.