mexiletine vs antiarrhythmic

mexiletine and antiarrhythmic both are nouns.

Word	Noun	Adjective	Verb	Adverb
mexiletine	Yes	No	No	No
antiarrhythmic	Yes	No	No	No

As nouns, antiarrhythmic is a hypernym of mexiletine; that is, antiarrhythmic is a word with a broader meaning than mexiletine:

mexiletine: antiarrhythmic drug (trade name Mexitil) used to treat ventricular arrhythmias
antiarrhythmic: a drug used to treat an abnormal heart rhythm

Other hypernyms of mexiletine include antiarrhythmic drug, antiarrhythmic medication.

mexiletine (noun)	antiarrhythmic (noun)
antiarrhythmic drug (trade name Mexitil) used to treat ventricular arrhythmias	a drug used to treat an abnormal heart rhythm