labetalol vs blocking agent

labetalol and blocking agent both are nouns.

Word	Noun	Adjective	Verb	Adverb
labetalol	Yes	No	No	No
blocking agent	Yes	No	No	No

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

labetalol: antihypertensive drug (trade names Trandate and Normodyne) that blocks alpha and beta-adrenergic receptors of the sympathetic nervous system (leading to a decrease in blood pressure)
blocking agent: a class of drugs that inhibit (block) some biological process

Other hypernyms of labetalol include antihypertensive, antihypertensive drug, blocker.

labetalol (noun)	blocking agent (noun)
antihypertensive drug (trade names Trandate and Normodyne) that blocks alpha and beta-adrenergic receptors of the sympathetic nervous system (leading to a decrease in blood pressure)	a class of drugs that inhibit (block) some biological process