A histamine H1 receptor antagonist (IC75 = 0.0016 μg/ml for reversal of histamine-induced spasms in isolated guinea pig ileum); protects against intravenous histamine-induced death (PD50 = 0.15 mg/kg) and delays induction of aerosolized histamine-induced coughing (ED100sec = 0.44 mg/kg) in guinea pigs; prevents histamine-induced PCA in rabbits at 20 mg/kg; reduces respiratory resistance and hypersecretion of tracheobronchial fluid in a dog model of histamine-induced asthma ,