Lyric discussion by foreverdrone 

Cover art for Phenagen lyrics by Public Image Ltd.

it's actually spelt "Phenergan", which is a trade name for promethazine (hey, I know it's not as if Lydon was a pharmacist...anyway I'm something of an amateur pharmacist, considering my health and all the different meds they've tried on me). in large doses promethazine is an antipsychotic...same family as Thorazine.

more commonly it's prescribed in small doses to reduce nausea, often in suppository form (in case the patient can't keep down a pill). many years ago in the States, it was standard operating procedure to give Phenergan to children in hospitals, several times a day. between the effects of the drug--and the method of administration--it was very effective in keeping kids quiet.

they just assumed all kids would be disruptive unless they were sedated. i know hospitals are frightening when you're little, but... well, that's how things used to be. their only concern was maintaining order; these were in the days before anyone wondered whether overmedicating might be a bad idea.