Comparison of Bitolterol Mesylate and Isoproterenol by Metered-Dose Inhaler for Regular, Long-Term Treatment in Asthmatic Children

Abstract

The objective of this study was to compare the efficacy and safety of bitolterol mesylate and isoproterenol hydrochloride, two sprays by metered-dose inhaler three times a day for 3 months in 240 asthmatic children ages 4-12 years. In this double-blind, randomized, parallel, multicenter study, patients received daily bitolterol mesylate or isoproterenol and were evaluated in the office at the beginning of the study and on 3 additional test days at 1-month intervals. They were evaluated by physical exam and ECG, blood and urine analyses, and spirometry for 8 hours after two sprays of the appropriate study aerosol. Theophylline was withheld for 24 hours and the study drug for 12 hours before office study days. All regular asthma medications were continued together with the bitolterol mesylate or isoproterenol between study days. Bronchodilation >15% above baseline occurred in <5 minutes with both treatments. Median durations of action were 3.1-4.4 and 1.2-2.2 hours with bitolterol mesylate and isoproterenol, respectively. Adverse effects were few and did not differ between drugs.