rifampin vs antibacterial drug

rifampin and antibacterial drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
rifampin	Yes	No	No	No
antibacterial drug	Yes	No	No	No

As nouns, antibacterial drug is a hypernym of rifampin; that is, antibacterial drug is a word with a broader meaning than rifampin:

rifampin: an antibacterial drug (trade names Rifadin and Rimactane) used to treat tuberculosis
antibacterial drug: any drug that destroys bacteria or inhibits their growth

Other hypernyms of rifampin include antibacterial, bactericide.

rifampin (noun)	antibacterial drug (noun)
an antibacterial drug (trade names Rifadin and Rimactane) used to treat tuberculosis	any drug that destroys bacteria or inhibits their growth