Pepto-bismal vs gastric antacid

Pepto-bismal and gastric antacid both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pepto-bismal	Yes	No	No	No
gastric antacid	Yes	No	No	No

As nouns, gastric antacid is a hypernym of Pepto-bismal; that is, gastric antacid is a word with a broader meaning than Pepto-bismal:

Pepto-bismal: an antacid
gastric antacid: an agent that counteracts or neutralizes acidity (especially in the stomach)

Other hypernyms of Pepto-bismal include alkaliser, alkalizer, antacid, antiacid.

Pepto-bismal (noun)	gastric antacid (noun)
an antacid	an agent that counteracts or neutralizes acidity (especially in the stomach)