Phenergan vs promethazine

Phenergan and promethazine both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phenergan	Yes	No	No	No
promethazine	Yes	No	No	No

As nouns, Phenergan and promethazine are synonyms defined as:

Phenergan and promethazine: antihistamine (trade name Phenergan) used to treat allergies; also an antiemetic used to treat motion sickness

Phenergan (noun)	promethazine (noun)
antihistamine (trade name Phenergan) used to treat allergies; also an antiemetic used to treat motion sickness	antihistamine (trade name Phenergan) used to treat allergies; also an antiemetic used to treat motion sickness