ddI vs antiviral drug

ddI and antiviral drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
ddI	Yes	No	No	No
antiviral drug	Yes	No	No	No

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

ddI: an antiviral drug used to combat HIV infection, a reverse transcriptase inhibitor
antiviral drug: any drug that destroys viruses

Other hypernyms of ddI include antiviral, antiviral agent.

ddI (noun)	antiviral drug (noun)
an antiviral drug used to combat HIV infection, a reverse transcriptase inhibitor	any drug that destroys viruses