Wiktionary
pillhead
n. (context slang English) A person who habitually takes tranquilizers, amphetamines, barbiturates, and other drugs, in pill or capsule form.
Usage examples of "pillhead".
Car thief, great banjo player, and the first serious pillhead I ever met.
One of them was possibly a pillhead and a pervert The one that killed himself.
Like those two weirdo prickhikers, and Sandy Pawku, and the Oakland hippie chick who must have been one of that Oakland bunch of pillheads who lured Houlihan back down to Mexico last month.
A pillhead, a heroin user, but a soldier who had re-upped to stay in Vietnam.