Butyfentanyl Powder (not to be confused with 3-methylfentanylhttp://: https://globalresearchemvendor.com/product/butyfentanyl/) 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. This document also states that the article describing its clinical effects (analgesic studies, m-, d-, k-Opioid receptor binding and in vitro measures of drug efficacy, antinociceptive and narcotic properties) was published in 1987. It is an agonist at mu opioid receptors. Butyfentanyl has no current legitimate clinical applications, but anecdotal reports indicate it may occasionally be surfacing on the grey-market as a recreational drug. This compound is a schedule I controlled substance in the USA because it is a positional isomer of 3-Methylfentanyl.