"In the last several years, U.S. Law Enforcement has seen a dramatic increase in the availability of dangerous synthetic opioids. A large majority of these synthetic opioids are structural derivatives of the synthetic drug 'fentanyl.' Fentanyl is a synthetic opioid currently listed as a Schedule II prescription drug that mimics the effects of morphine in the human body, but has potency 50--100 times that of morphine. Due to the high potency and availability of fentanyl, both transnational and domestic criminal organizations are increasingly utilizing these dangerous synthetic opioids as an adulterant in heroin and other controlled substances. The presence of these synthetic opioids in the illicit U.S. drug market is extremely concerning as the potency of these drugs has led to a significant increase in overdose incidents and overdose‐ related deaths throughout the nation."
US Drug Enforcement Administration: https://www.dea.gov/