Fentanyl use has been linked with an increasing number of opioid-related deaths. The emergency department (ED) is a critical contact point for patients with opioid use disorder (OUD) to access basic healthcare. Little information is known about buprenorphine precipitated opioid withdrawal (BPOW). This study sought to examine the rates of BPOW in patients who used fentanyl and received buprenorphine in the ED.

A retrospective cohort study was conducted in a single emergency department in an urban city and included patients who reported use of fentanyl and who received buprenorphine for opioid withdrawal. The primary outcome was occurrence of BPOW, in which we assessed for interrater reliability between data abstractors. Data extraction included patients' demographic characteristics, date of service, length of stay, Clinical Opiate Withdrawal Scale (COWS) score assessments, dosages of administered buprenorphine, occurrence of BPOW, and ED disposition.

Over the course of 28 months, buprenorphine was administered 113 patients (12.5 %) who reported using fentanyl prior to their ED presentation. The majority of patients identified as White (49 %), and most patients presented with a chief complaint other than specific opioid related concerns. Fifty-one patients (45 %) had an initial COWS score documented, with a median score of 11. Three patients (2.6 %) had BPOW, two of whom required intensive care unit (ICU) admission.

We demonstrate that the prevalence of BPOW is low in a cohort of patients who use fentanyl. When precipitated withdrawal does occur, however, it can be severe and require intensive treatment, ICU admission, and prolonged hospital stay.