ChlorpheniramineHistamine H1 AntagonistsReceptors, Histamine H1ButyrophenonesDimethindeneHistamine AntagonistsTriprolidineHistamineReceptors, Histamine H2DimapritMetiamideReceptors, HistamineBurimamideHistamine H2 AntagonistsHydroxyzineClemastineKetotifenCimetidineMethylhistaminesHistamine AgonistsPyrilamineDiphenhydramineStereoisomerismImpromidine