Effects of azelastine on allergen- and exercise-induced asthma.

The effects of the new anti-allergic drug, azelastine, on allergen- and exercise-induced asthma were studied. In six allergen inhalation tests for five asymptomatic asthmatic patients, the maximum percentage fall in FEV1.0 immediately after inhalation of allergen extract was 37.2 +/- 6.4 per cent (mean +/- SEM). As compared with a placebo, the maximum percentage fall in FEV1.0 with azelastine after inhalation of allergen extract in the same manner as with the placebo was 17.3 +/- 6.9 per cent. The difference was statistically significant (p less than 0.05). The percentage fall in FEV1.0 with placebo and azelastine in late asthmatic response (n = 4) was 36.0 +/- 5.3 per cent and 10.0 +/- 5.2 per cent, respectively. The difference was also statistically significant (p less than 0.01). An exercise test was carried out on seven asymptomatic asthmatic patients using an inclined treadmill. The maximum percentage fall in FEV1.0 without drugs, with diphenhydramine and azelastine was 38.9 +/- 5.0 per cent, 20.1 +/- 3.8 per cent and 11.3 +/- 3.1 per cent, respectively. Significant differences were found among each group (p less than 0.05). Azelastine was regarded as having sufficient potency to inhibit exercise-induced asthma; however, placebo effects cannot be ruled out with regard to the effects of diphenhydramine. These results suggests that chemical mediator release is involved not only in allergen-induced asthma but also in exercise-induced asthma, suggesting the clinical utility of azelastine.