esmolol vs beta-blocking agent

esmolol and beta-blocking agent both are nouns.

Word	Noun	Adjective	Verb	Adverb
esmolol	Yes	No	No	No
beta-blocking agent	Yes	No	No	No

As nouns, beta-blocking agent is a hypernym of esmolol; that is, beta-blocking agent is a word with a broader meaning than esmolol:

esmolol: intravenous beta blocker (trade name Brevibloc) that acts for only a short time; used primarily for cardiac arrhythmias
beta-blocking agent: any of various drugs used in treating hypertension or arrhythmia; decreases force and rate of heart contractions by blocking beta-adrenergic receptors of the autonomic nervous system

Other hypernyms of esmolol include beta-adrenergic blocker, beta-adrenergic blocking agent, beta blocker.

esmolol (noun)	beta-blocking agent (noun)
intravenous beta blocker (trade name Brevibloc) that acts for only a short time; used primarily for cardiac arrhythmias	any of various drugs used in treating hypertension or arrhythmia; decreases force and rate of heart contractions by blocking beta-adrenergic receptors of the autonomic nervous system