Lyric discussion by tikbalang 

Cover art for Methadone Pretty lyrics by Manic Street Preachers

Since methadone was used to kick heroin, and 'pretty' was sort of a faint praise coming from such an extensive vocabulary as the Manics', I figured that "methadone pretty" would be the logical progression of "heroin chic."

"Pump it up, safer than a suicide" and "Gonna stay a terminal young thing" could refer to the waif model's sick or prepubescent appearance: where, instead of dying young and being remembered only at that stage, they can freeze themselves in an unnatural perpetual adolescence.

They, and the culture that spawned them, will go over the hill, and be that much worse for all the contortions made to maintain an ideal; their 'retirement' recognized in faint praise and drug rehab.