Butyrnorfentanyl or butyrylnorfentanyl is an inactive synthetic opioid analgesic drug precursor. It is an analog of fentanyl.
See also 3-Methylbutyrfentanyl 4-Fluorobutyrfentanyl 4-Fluorofentanyl α-Methylfentanyl Acetylfentanyl Benzylfentanyl Furanylfentanyl Homofentanyl List of fentanyl analogues
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