The common effective dose of Promethazine HCl Syrup (promethazine hydrochloride syrup basic) Plain with the Lively therapy of nausea and vomiting in children or adults is 25 mg.Leukopenia and agranulocytosis have been claimed, commonly when Promethazine HCl Syrup (promethazine hydrochloride syrup basic) Plain has actually been used in Affiliation w