Double-blind, dose-response study of metaproterenol inhalant solution in children with acute asthma

One hundred children, aged 6 to 12 years, with acute asthma received nebulized therapy with saline, 5, 10, or 15 mg of metaproterenol aerosol solution according to a prerandomized, double-blind protocol. Pulmonary function and cardiac function were assessed for 60 minutes. All patients then received 5 mg of metaproterenol aerosol solution, and observation continued for another 30 minutes. The best response to therapy in terms of rise in FEV1, forced expiratory flow rate between 25% and 75% of FVC, and area under the curve (change in lung function with time) occurred with 5 and 10 mg of metaproterenol. The highest dose, 15 mg, produced significantly less bronchodilation. Although there were no electrocardiographic abnormalities, pulse rate was significantly higher with 10 and 15 mg of metaproterenol than with 5 mg. Five milligrams of metaproterenol aerosol solution is the optimal bronchodilating dose for treating acute asthma in children. Repeating this dose provides some additional bronchodilation and is well tolerated.