Methedrine (n.)

univalent hydrocarbon radical, 1840, from German methyl (1840) or directly from French méthyle, back-formation from French méthylène (see methylene). Ultimately from Greek methy "wine" + hylē "wood." 

trade name of a type of amphetamine, 1933, registered as a proprietary name 1935 by Smith, Kline & French Laboratories, from benzoic (see benzene) + chemical suffix -edrine from ephedrine, etc. It is a carbonate of benzyl-methyl-carbinamine. Slang shortening benny is attested by 1955.

colloquial abbreviation of methedrine, attested from 1967.