A histamine H1 receptor antagonist (apparent Kis 1 41 and 1 62 nM using guinea pig cerebellar and lung membranes respectively) and mast cell stabilizer inhibits IgE-induced histamine TNF-a and IL-10 secretion in human CBMCs at 0 1 g/ml inhibits histamine-induced cutaneous vascular permeability in rats and bronchoconstriction in anesthetized guinea pigs (ID50s 5 and 0 1 mg/kg respectively) inhibits dye leakage into the conjunctiva in a rat model of passive anaphylaxis reaction-induced vascular hyperpermeability of the conjunctiva (ID50 9 7 mg/kg p o ) topical administration reduces lid edema tearing and redness as well as the number of neutrophils and eosinophils in the lid fornix in a mouse model of atopic conjunctivitis