methadone

 
Pronunciation: /ˈmɛθədəʊn/

noun

[mass noun]
  • a powerful synthetic analgesic drug which is similar to morphine in its effects but less sedative and is used as a substitute drug in the treatment of morphine and heroin addiction.

Origin:

1940s: from its chemical name, (6-di)meth(yl)a(mino-4,4-)d(iphenyl-3-heptan)one