Someone with an addiction or severe medical condition that requires copious amounts of prescription medication. It applies to legit and illegal prescriptions.
I know a Drugstore Cowgirl, so afraid of getting bored. She's always running from something. So many things ignored"--Lyrics to 311's "Beautiful Didaster
A loose women that will ride any man who has drugs.
That Sadi is a ho, fuckin' drugstore cowgirl.