Dose-related effects of nebulized metaproterenol in asthmatic children

The dose-related effects of inhaled 5% metaproterenol solution in asthmatic children between the ages of six and 12 years with acute bronchospasm were evaluated. Tests included FEV_1.0, FEF_25–75, and PEFR. For entry into the study, subjects were required to have an FEV_1.0 or an FEF_25–75 less than 80% of the child’s predicted normal value based on height and race. Sixty children were randomly assigned in double-blind fashion to receive one of four different doses of 5% metaproterenol inhalant solution: 0.0 ml (placebo), 0.1 ml, 0.2 ml, or 0.3 ml. Drug efficacy was assessed by spirometry using a DeVilbiss Surveyor I spirometer. Spirometry was performed prior to inhalation of the test dose (baseline) and four times after inhalation: Immediately after and 15, 30, and 60 minutes after inhalation. Patients in the three treated groups had significantly higher peak post-dose FEV_1.0 and FEF_25–75 than the placebo group but were not significantly different from one another. There was a significant relationship between dose and incidence of side effects. These results suggest that 0.1 ml (5 mg) of nebulized metaproterenol may provide as much bronchodilatation as higher doses with fewer side effects.