Tags: Drug.
Butyr-fentanyl or butyrylfentanyl (not to be confused with 3-methylfentanyl) is a potent short-acting synthetic opioid analgesic drug. It is an analogue of fentanyl with around one quarter the potency of fentanyl. One of first mentions of this drug can be found in document written by The College on Problem of Drug Dependence where it is mentioned as N-butyramide fentanyl analog.
