Therapeutic Drug Monitoring in Buprenorphine/Naloxone Treatment for Opioid Use Disorder: Clinical Feasibility and Optimizing Assay Precision.

INTRODUCTION: Compliance with sublingual buprenorphine/naloxone (SL-BUP/NX) is associated with higher abstinence from illicit opioid use. Therapeutic drug monitoring (TDM) has been recommended for adherence monitoring of buprenorphine (BUP) maintenance treatment for opioid use disorder (OUD), but to date there have been no reported clinical applications. In this TDM feasibility study, we investigated BUP assay precision in 15 adults with OUD who had been stabilized on buprenorphine/naloxone. METHODS: Using solid phase extraction, BUP recovery was contrasted at 100 mMol and 1 Molar of acetic acid wash solution. Precision was determined by applying the condition generating highest recovery using 0.2 ng/mL and 10 ng/mL standards. Four blood samples were drawn to examine the BUP peak and trough plasma concentrations, and BUP elimination rate was estimated. BUP recovery was examined again in a random sample and contrasted with the concentration predicted applying first-order kinetics. RESULTS: Higher BUP recovery was achieved with 1 Molar wash (94.3%; p=0.05). Precision ranged from 15-20%. The estimated limit of detection (LoD) and limit of quantitation (LoQ) were 0.02 and 0.069 ng/mL, respectively. BUP peak and trough concentrations were successfully examined, and BUP trough concentrations were replicated confirming steady state. BUP concentrations were predicted at a variance of -7.20% to 1.54 %. CONCLUSIONS: TDM for BUP maintenance treatment of OUD is feasible, and simple adjustment of the assay conditions enhances BUP recovery.

Perspectives on rapid fentanyl test strips as a harm reduction practice among young adults who use drugs: a qualitative study.

BACKGROUND: In 2016, drug overdose deaths exceeded 64,000 in the United States, driven by a sixfold increase in deaths attributable to illicitly manufactured fentanyl. Rapid fentanyl test strips (FTS), used to detect fentanyl in illicit drugs, may help inform people who use drugs about their risk of fentanyl exposure prior to consumption. This qualitative study assessed perceptions of FTS among young adults. METHODS: From May to September 2017, we recruited a convenience sample of 93 young adults in Rhode Island (age 18-35 years) with self-reported drug use in the past 30 days to participate in a pilot study aimed at better understanding perspectives of using take-home FTS for personal use. Participants completed a baseline quantitative survey, then completed a training to learn how to use the FTS. Participants then received ten FTS for personal use and were asked to return 2-4 weeks later to complete a brief quantitative and structured qualitative interview. Interviews were transcribed, coded, and double coded in NVivo (Version 11). RESULTS: Of the 81 (87%) participants who returned for follow-up, the majority (n = 62, 77%) used at least one FTS, and of those, a majority found them to be useful and straightforward to use. Positive FTS results led some participants to alter their drug use behaviors, including discarding their drug supply, using with someone else, and keeping naloxone nearby. Participants also reported giving FTS to friends who they felt were at high risk for fentanyl exposure. CONCLUSION: These findings provide important perspectives on the use of FTS among young adults who use drugs. Given the high level of acceptability and behavioral changes reported by study participants, FTS may be a useful harm reduction intervention to reduce fentanyl overdose risk among this population. TRIAL REGISTRATION: The study protocol is registered with the US National Library of Medicine, Identifier NCT03373825, 12/24/2017, registered retrospectively. https://clinicaltrials.gov/ct2/show/NCT03373825?id=NCT03373825&rank=1.