101345-71-5 117268-95-8 A 3331 Acetamide, N-((3R,4S)-1-(2-(4-ethyl-4,5-dihydro-5-oxo-1H-tetrazol-1-yl)ethyl)-3-methyl-4-piperidinyl)-N-(2-fluorophenyl)-2-methoxy-, monohydrochloride, rel- Acetamide, N-(1-(2-(4-ethyl-4,5-dihydro-5-oxo-1H-tetrazol-1-yl)ethyl)-3-methyl-4-piperidinyl)-N-(2-fluorophenyl)-2-methoxy-, monohydrochloride, cis-(+-)- BRIFENTANIL HYDROCHLORIDE Brifentanil hydrochloride [USAN]