LACK OF EFFECT OF CETIRIZINE ON EARLY AND LATE ASTHMATIC RESPONSE AFTER ALLERGEN CHALLENGE

Background: Cetirizine hydrochloride has proved effective in reducing allergic symptoms and can inhibit the infiltration of eosinophils in a llergic late-phase responses in the skin. Because eosinophils are like ly to play an important role in allergic late-phase reactions, we stud ied the effect of cetirizine on early and late asthmatic reactions and on levels of eosinophil cationic protein (ECP) in the blood after all ergen challenge. Methods: The effect of 15 mg cetirizine given twice d aily was studied in 16 patients allergic to house dust mites in a doub le-blind, placebo-controlled study. patients were treated for 3 weeks. Before and after treatment, bronchial challenges with house-dust mite s were performed Blood ECP levels were measured 6 hours after challeng e. Methacholine provocation was performed 72 hours before and 24 hours after each challenge. Results: Early and late asthmatic response-meas ured as mean maximal fall in forced expiratory volume in 1 second (FEV (1)) and the provocative dose of allergen that causes a 15% fall in FE V(1) (PD15 allergen) - were not significantly reduced after treatment with cetirizine, compared with placebo. There was also no significant effect on the concentration of methacholine, which causes a 20% fall i n FEV(1) (PC20 methacholine). The increase in the level of ECP in the blood after allergen challenge was reduced after cetirizine treatment, compared with placebo but this difference was not statistically signi ficant. Conclusion: Eighteen days of treatment with cetirizine did not significantly reduce the intensity of the early and late asthmatic re sponses.