antitussive vs medicinal drug

antitussive and medicinal drug both are nouns.

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

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

antitussive: any medicine used to suppress or relieve coughing
medicinal drug: (medicine) something that treats or prevents or alleviates the symptoms of disease

Other hypernyms of antitussive include medicament, medication, medicine.

antitussive (noun)	medicinal drug (noun)
any medicine used to suppress or relieve coughing	(medicine) something that treats or prevents or alleviates the symptoms of disease