/meth"euh dohn'/ , n. Pharm.
a synthetic narcotic, C 21 H 28 ClNO, similar to morphine but effective orally, used in the relief of pain and as a heroin substitute in the treatment of heroin addiction.
Also, methadon /meth"euh don'/ .
[ 1945-50, Amer.; METH(YL) + A(MINO) + D(IPHENYL) + (HEPTAN)ONE ]