Detection of carfentanil in a cluster of patients without associated mortality: Response to Chhabra et al.

Abstract

An analysis of fentanyl analog exposures in Cook County, Illinois recently published in this journal by Chhabra et al. found that more than half of urine drug screens detected at least one fentanyl analog or synthetic opioid (1). The relative ease of manufacturing and costcutting measures in the illicit drug industry has caused a flooding of the market with synthetic opioids, which is reflected in reported overdose deaths, as synthetic opioid-involved deaths increased 1040% from 2013 to 2019 (2). Use and overdose of carfentanil specifically has increased rapidly around the United States since it was first identified in patient samples in 2016 (3). Given the high potency of the drug (approximately 10,000 times as potent as morphine), most cases of carfentanil use have been identified postmortem, which poses a serious threat to patients with opioid use disorder. To support the conclusions made by Chhabra et al., we report a patient cluster in Central New York, in which seven patients in a single methadone opioid treatment program (OTP) tested positive for urine carfentanil and/or the carfentanil metabolite norcarfentanil by LC-MS/MS (4) (Table 1). Overall, we found 12 positive results from 166 specimens collected from 119 individual patients between October 2020 and January 2021. Surprisingly, chart review indicated that carfentanil was detected incidentally, and not as a result of reported overdose. All patients claimed that they were unaware that they had used carfentanil, and 4 of the 7 patients were positive for carfentanil before they had initiated methadone treatment. In addition to the corresponding article (1), this patient cluster reflects an increasing number of carfentanil cases appearing in the state of New York, and a trend of patients that survive carfentanil use (1,5). Further, a recent evaluation of commercially available rapid drug detection kits demonstrated a poor crossreactivity and detection abilities for synthetic fentanyl analogs (6). Taken together, it is imperative for healthcare workers and public health officials to provide adequate patient education and harm reduction measures for patients in OTPs, and to increase surveillance of carfentanil and other synthetic opioid analogs. The retrospective data in this study was granted an exemption status from our institution’s IRB.