metformin vs antidiabetic drug

metformin and antidiabetic drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
metformin	Yes	No	No	No
antidiabetic drug	Yes	No	No	No

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

metformin: an antidiabetic drug (trade name Glucophage) prescribed to treat type II diabetes
antidiabetic drug: a drug used to treat diabetes mellitus

Other hypernyms of metformin include antidiabetic.

metformin (noun)	antidiabetic drug (noun)
an antidiabetic drug (trade name Glucophage) prescribed to treat type II diabetes	a drug used to treat diabetes mellitus