Notes from the Field : Increased Incidence of Fentanyl-Related Deaths Involving Para -fluorofentanyl or Metonitazene — Knox County, Tennessee, November 2020–August 2021

Abstract

Data from the National Center for Health Statistics indicate that drug overdose deaths in the United States have increased by 28.5% during 2020–2021, from 78,056 during a 12-month period ending in April 2020 to 100,306 during the same period in 2021 (1). Approximately 75% of drug overdose deaths during 2020 involved opioids. With illicitly manufactured fentanyl continuing to supplant the heroin market, and increasing illicit use of counterfeit pills containing either fentanyl, various fentanyl-related compounds, or other opioids, the risk for drug overdose deaths remains high (2). Recently, para-fluorofentanyl, a substance from research efforts in the 1960s and referred to as “China-white” before it was classified as a schedule I substance in 1986, has begun to reemerge on the illicit drug market.* It is found in heroin packets, counterfeit pills, and is reported in autopsy findings and supporting toxicology results.† More recently, another class of compounds known as benzimidazole-opioids have begun appearing in cities across the country as adulterants in the heroin supply, adding a new threat to public health (3). Discovered through research for new opioid analgesics in the late 1950s, this class of opioid receptor agonists did not receive market authorization for therapeutic use. Based on law enforcement seizure data from the National Forensic Laboratory Information System (NFLIS)§ and medical examiner reports as described below, metonitazene, a benzimidazole-opioid, and para-fluorofentanyl (both in combination with fentanyl), are being encountered more often in the United States.