brifentanil brifentanil brifentanil (a-3331) is an opioid analgesic that is an analogue of fentanyl and was developed in the early 1990s. brifentanilclinical dataother namesbrifentanilatc codenoneidentifiers iupac name n- -3-methylpiperidin-4-yl]-n-(2-fluorophenyl)-2-methoxyacetamide cas number101345-71-5pubchem cid60672chemspider54682 yunii6gdt77pqbwchemblchembl2220476comptox dashboard (epa)dtxsid20143867 chemical and physical dataformulac20h29fn6o3molar mass420.489 g·mol−13d model (jsmol)interactive image smiles fc1ccccc1n(c(=o)coc)3ccn(ccn2\n=n/n(c2=o)cc)c3c inchi inchi=1s/c20h29fn6o3/c1-4-25-20(29)26(23-22-25)12-11-24-10-9-17(15(2)13-24)27(19(28)14-30-3)18-8-6-5-7-16(18)21/h5-8,15,17h,4,9-14h2,1-3h3/t15-,17+/m1/s1 ykey:kkmgctvjcqyqpv-wbvhzdcisa-n y (verify) brifentanil is most similar to highly potent, short-acting fentanyl analogues such as alfentanil. the effects of brifentanil are very similar to those of alfentanil, with strong but short lasting analgesia and sedation, and particularly notable itching and respiratory depression. side effects of fentanyl analogs are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression, which can be life-threatening. fentanyl analogs have killed hundreds of people throughout europe and the former soviet republics since the most recent resurgence in use began in estonia in the early 2000s, and novel derivatives continue to appear. the risk of respiratory depression is especially high with potent fentanyl analogues such as alfentanil and brifentanil, and these drugs pose a significant risk of death if used outside of a hospital setting without an appropriate artificial breathing apparatus available.