Furanyl fentanyl is a DEA Schedule I controlled substance. Substances in the DEA Schedule I have no currently accepted medical use in the United States, a lack of accepted safety for use under medical supervision, and a high potential for abuse.
Furanylfentanyl (Fu-F) is an opioid analgesic that is an analog of fentanyl and has been sold as a designer drug that is approximately one fifth as potent as fentanyl.