The chemical Olopatadine hydrochloride has a designated molecular formula of C21H24ClNO3 and a molecular weight of 373.877 g/mol. Synonyms may include: Patanol, KW 4679, ALO4943A, Pataday, Olopatadine HCl, UNII-2XG66W44KF, Patanase, DE 114, Allelock, Olopine, Patadine, ALO 4943A, Olopax, Pazeo (ChemID). Olopatadine hydrochloride has been assigned a MeSH pharmacological action of: Histamine H1 Antagonist.