Dose-response relationship of inhaled metaproterenol sulfate in preschool children with mild asthma.

The dose-response relationship of single doses of nebulized metaproterenol sulfate 5% inhalant solution was evaluated by placebo-controlled, parallel-group study of 30 children, aged 3 to 6 years old, with stable asthma. Total respiratory resistance, the primary variable used to assess response, was measured by the forced oscillation method for a period of 6 hours from the start of inhalation. When comparisons were made between metaproterenol sulfate and saline, only 0.01 and 0.02 mL/kg showed significant bronchodilation (P less than .05) in percent change from baseline and area under the curve. However, no significant differences were seen between these doses. Moreover, the effect was sustained for 3 hours with both higher doses. Minimal side effects were observed. Metaproterenol sulfate 5% inhalant solution at a dose of 0.01 mL/kg seems to be optimal to elicit significant and sustained bronchodilatory response in preschool children with mild asthma.