Buprenorphine/naloxone associated with a reduced odds of fentanyl exposure among a cohort of people who use drugs in Vancouver, Canada

Abstract

BackgroundLittle is known about the relationship between opioid agonist therapy (OAT) and fentanyl use, specifically. This study aimed to estimate the association between current use of different forms of OAT, including methadone, buprenorphine/naloxone (BUP/NX), slow release oral morphine (SROM), or injectable opioid agonist treatment (iOAT), and the likelihood of a fentanyl-positive urine drug test (UDT) as compared to no OAT. MethodsData were obtained from three community-recruited prospective cohort studies of people who use drugs in Vancouver, Canada from December 2016 through November 2018. Using multivariable Generalized Estimating Equations (GEE), we examined the association between current use of each form of OAT, as compared to no OAT, and fentanyl-positive UDT among participants who use opioids. ResultsThe 915 participants contributed 2112 UDTs over a median of two follow-up visits. The majority of UDTs (74.9 %) were positive for fentanyl. After adjustment for a priori defined confounding factors, compared to no OAT, current use of BUP/NX was associated with lower odds of fentanyl-positive UDT (odds ratio [OR] = 0.36, 95 % confidence interval [CI]: 0.22–0.58) while current use of methadone (OR = 0.84, 95 % CI: 0.65–1.07), iOAT (OR = 1.30, 95 % CI: 0.75–2.28), and SROM (OR = 1.34, 95 % CI: 0.74–2.43) were not. ConclusionsIn this cohort of people who use opioids in Vancouver, only use of BUP/NX was associated with lower odds of fentanyl-positive UDT. Our findings highlight high rates of ongoing fentanyl use despite the use of OAT and support the expansion of BUP/NX for the treatment of people who use fentanyl.