neuroleptic agent vs major tranquillizer

neuroleptic agent and major tranquillizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
neuroleptic agent	Yes	No	No	No
major tranquillizer	Yes	No	No	No

As nouns, neuroleptic agent and major tranquillizer are synonyms defined as:

neuroleptic agent and major tranquillizer: tranquilizer used to treat psychotic conditions when a calming effect is desired

neuroleptic agent (noun)	major tranquillizer (noun)
tranquilizer used to treat psychotic conditions when a calming effect is desired	tranquilizer used to treat psychotic conditions when a calming effect is desired