antiemetic drug vs medication

antiemetic drug and medication both are nouns.

Word	Noun	Adjective	Verb	Adverb
antiemetic drug	Yes	No	No	No
medication	Yes	No	No	No

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

antiemetic drug: a drug that prevents or alleviates nausea and vomiting
medication: (medicine) something that treats or prevents or alleviates the symptoms of disease

Other hypernyms of antiemetic drug include medicament, medicinal drug, medicine.

antiemetic drug (noun)	medication (noun)
a drug that prevents or alleviates nausea and vomiting	the act of treating with medicines or remedies
	(medicine) something that treats or prevents or alleviates the symptoms of disease