: a crystalline antihistamine drug derived from phenothiazine and used chiefly in the form of its hydrochloride C17H20N2S·HCl see phenergan

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“Promethazine.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/promethazine. Accessed 7 Jul. 2026.

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