antidiarrheal vs medicinal drug

antidiarrheal and medicinal drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
antidiarrheal	Yes	No	No	No
medicinal drug	Yes	No	No	No

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

antidiarrheal: a drug used to control or stop diarrhea
medicinal drug: (medicine) something that treats or prevents or alleviates the symptoms of disease

Other hypernyms of antidiarrheal include medicament, medication, medicine.

antidiarrheal (noun)	medicinal drug (noun)
a drug used to control or stop diarrhea	(medicine) something that treats or prevents or alleviates the symptoms of disease