Some actual (not imagined) drug references:
“Strike a Match and Light Another” by Cat Mother and the All-Night Newboys (probably the best marijana song ever).
“I Like Marijuana” by David Peel and the Lower East Side, part of their album Have a Marijuana. Just about all the other songs on the album has marijuana references.
“Cocaine” by Eric Clapton
“Mother’s Little Helper” by the Rolling Stones
“I Get A Kick Out of You” by Cole Porter (for the line “I get no kick from cocaine.”)
“The Needle and the Damage Done” by Neil Young
“One Toke Over the Line” by Brewer and Shipley (They admitted the phrase meant roughly, “just enough marijuana to give you a buzz”)
“Heroin” by Lou Reed
“White Rabbit” by Jefferson Airplane