EFFECT OF TOPICAL LEVOCABASTINE ON NASAL RESPONSE TO ALLERGEN CHALLENGE AND NASAL HYPERREACTIVITY IN PERENNIAL RHINITIS

Background: It has been demonstrated that some oral antihistamines red uce nasal nonspecific reactivity and that topical levocabastine reduce s cellular influx after nasal allergen challenge. This suggests that a ntihistamines possess other properties besides classical H-1-receptor antagonism. Objective: To evaluate the effect of 1 week's treatment wi th topical levocabastine on the nasal clinical response, inflammatory mediators, and nasal hyperreactivity. Methods: In a double-blind, plac ebo-controlled, 2-period, 2-treatment, crossover study, 21 rhinitic pa tients allergic to house dust mite participated. After each treatment period patients were challenged with house dust mite extract. Symptom scores and nasal lavages were collected for nine and one-half hours af ter challenge. Allergen-induced nasal hyperreactivity was determined b y nasal methacholine challenge 24 hours after allergen challenge. A na sal histamine challenge was performed as well. Results: Patients showe d only an immediate nasal response. Levocabastine significantly reduce d the symptom score after 100 (P =.0063), 1000 (P =.0035), and 10,000 biological units (BU)/mL (P =.0013) of house dust mite extract. Albumi n influx and tryptase release were not significantly reduced by levoca bastine. No release of histamine and eosinophil cationic protein was s een. Levocabastine did not reduce nasal response to methacholine. Acti ve treatment significantly reduced histamine-induced nasal secretion ( P =.0009) and the number of sneezes (P =.0001). Conclusion: A signific ant effect of levocabastine was shown on the immediate clinical respon se to house dust mite and to histamine challenge only. Our findings su ggest that levocabastine is an effective H-1-receptor antagonist witho ut antiinflammatory properties.