为 上游充通大学 SHANGHAI JIAO TONG UNIVERSITY 1896 1920 1987 2006 Antihistamines H-R blocking drugs The first-generations has a relatively strong sedative effects Diphenhydramine Promethazine Tripelennamine TONG UNIVERSITY Chlorpheniramine ●●●●●●H1 -R blocking drugs The first –generations has a relatively strong sedative effects Diphenhydramine Promethazine Tripelennamine Chlorpheniramine …… Antihistamines