Terbutaline elixir in preschool children with chronic asthma.

In a double-blind, single-dose trial asthmatic children, ages two to six years, received 25, 50 or 100 ug/kg terbutaline and placebo on four consecutive days. After ingestion of all doses and placebo mean pulmonary index score and mean total respiratory resistance (Rrs), measured by forced oscillation decreased significantly at 0.5, 1, 2, 3 and 4 hours, with maximal decrease at two hours. A dose response was apparent but was significant only between doses of 25 ug/kg and 50 ug/kg at four hours. Adverse effects included elevation of heart rate two hours after the 100 ug/kg dose and tremor. In a subsequent nine-week, single-blind trial clinical wheezing was completely prevented by terbutaline 50 ug/kg tid in five of eight patients and by 75 or 100 ug/kg tid in two patients. Baseline Rrs did not decrease. No adverse ophthalmologic, hematologic or biochemical changes were observed.