EFFICACY AND SAFETY OF INHALED BITOLTEROL MESYLATE VIA METERED-DOSE INHALER IN CHILDREN WITH ASTHMA

Background: There have been numerous studies in asthmatic adults demon strating the efficacy and safety of bitolterol mesylate metered-dose i nhaler; however, only one additional study has examined bitolterol met ered-dose inhaler in pediatric asthma. Objective: To establish the saf ety and effectiveness of bitolterol mesylate metered-dose inhaler at o ne, two, and three inhalations in pediatric asthmatic patients 4 to 12 years of age. Methods: A multicenter, double-blind, randomized, cross over, placebo-controlled, dose-ranging study. Forty-six patients were evaluated in three centers. Patients were stratified by age, 4 to 6, 7 to 9, 10 to 12 years at each center. One, two, or three inhalations w ere administered along with an additional double-blind, randomized, pl acebo dose. Bronchodilation was defined as a 15% or greater increase i n FEV(1) over baseline. Onset, maximum improvement, and duration of ac tion were obtained for each patient. Serial pulse rate, blood pressure , and respiratory rate determinations were obtained for each patient. Results: Onset within five minutes occurred in 56.6% to 71% of patient s, depending on the dose. Mean maximum improvement, which was dose dep endent, overall ranged from 28.2% to 40.3% with a peak response in 66. 7 to 69.8 minutes. A direct relationship of magnitude with regard to d ose of bitolterol was observed, (P < .001). A significant correlation, r = .732, in response between bronchodilation and baseline FEV(1) was observed (P < .001). Median duration of action ranged from three to f our hours in responding patients across all doses. Up to 31% of patien ts had durations greater than eight hours after three inhalations, Adv erse effects were reported in five of 46 patients for all doses with m ild transient tremor occurring in two patients, 4.3%. Also, there was little effect on pulse rate, 2.2%. Conclusion: Bitolterol is an effect ive bronchodilator with durations of activity up to eight hours and mi nimal adverse effects in children.