Wiktionary
chlormezanone
n. A particular drug used to reduce anxiety and relax muscles.
Wikipedia
Chlormezanone
Chlormezanone (marketed under the brandname Trancopal or Fenaprim) is a drug used as an anxiolytic and a muscle relaxant.
Its use was discontinued in many countries from 1996 on, due to rare but serious cases of toxic epidermal necrolysis.