drug vs free-base

drug is a noun but free-base is not a noun.

Word	Noun	Adjective	Verb	Adverb
drug	Yes	No	Yes	No
free-base	No	No	Yes	No

As verbs, free-base is a hyponym of drug; that is, free-base is a word with a more specific, narrower meaning than drug:

Other hyponyms of drug include inject, snort, take a hit, base, drop, dope.

drug (noun)	free-base (noun)
a substance that is used as a medicine or narcotic

drug (verb)	free-base (verb)
administer a drug to	use (purified cocaine) by burning it and inhaling the fumes
use recreational drugs