EFFECT OF AZELASTINE ON THE SEASONAL INCREASE IN NONSPECIFIC BRONCHIAL RESPONSIVENESS TO METHACHOLINE IN POLLEN ALLERGIC PATIENTS - A RANDOMIZED, DOUBLE-BLIND PLACEBO-CONTROLLED, CROSSOVER STUDY

Azelastine, a phthalazinone derivative, is a new potent, long acting, orally active anti-allergic compound with particularly strong H-1-hist amine receptor antagonistic effects which has been proven to possess i n vitro and in vivo a number of anti-inflammatory properties. The aim of the present study was to investigate whether azelastine would be ab le to prevent and/or reverse the seasonal increase in non-specific bro nchial responsiveness to methacholine in pollen allergic patients. Twe lve atopic patients (5 males, mean age 31 years), skin positive exclus ively to grass and/or Parietaria pollen extract, with rhinitis and mil d asthma occurring in the spring for at least two years previously, we re studied. After a 2 week run-in period, oral azelastine, 4 mg twice daily, or placebo, was given for 2 weeks from the start of the pollen season, according to a randomized, double-blind design. After 2 weeks, the treatments were crossed over. During both the run-in and study pe riods, patients recorded rhinitis and asthma symptoms, additional anti histamine and bronchodilator drugs taken and peak expiratory flow meas urements. A methacholine inhalation test was carried out on four occas ions in each patient: before the run-in period, before the start of th e treatment, and at the end of the two 2 week treatment periods. Azela stine significantly reduced rhinitis symptoms and the need for antihis tamine drugs, whereas asthmatic symptoms, use of bronchodilator drugs, peak flow recordings and bronchial responsiveness to methacholine wer e unaffected by the treatment. Compliance level and adverse side-effec ts were not significantly different between active treatment and place bo. In the final subjective evaluation of the two treatments, eight ou t of 12 patients preferred azelastine. Thus, azelastine has been confi rmed to be effective and safe in the treatment of seasonal allergic rh initis. However, in our patients, we have not been able to demonstrate any anti-asthmatic action of the drug.