Aerosolized metaproterenol compared to subcutaneous epinephrine in the emergency treatment of acute childhood asthma.

In a double-blind, randomized trial, we compared the effects of aerosolized metaproterenol to subcutaneous epinephrine in 35 episodes of acute asthma in children between 6 and 19 years of age. Patients were randomized to two parallel groups and then received both a placebo medication and an active medication to a maximum of three treatments. Repeated treatments were given to 15 patients on metaproterenol and 12 patients on epinephrine. Initial improvement in PEFR and FEV1 were statistically significant and comparable in both groups. Patients receiving a second metaproterenol treatment had more improvement in respiratory rate and clinical score compared with those in the epinephrine group. There were fewer treatment failures in the metaproterenol group. Followup at 24 to 48 hours showed significant treatment failure differences between the two groups (metaproterenol = 0, epinephrine = 5; p less than 0.05). Side effects were similar in both groups; in all instances they were mild, and their frequency did not increase in patients receiving repeated doses of medications. In conclusion, aerosolized metaproterenol was well tolerated in acute childhood asthma in repeated doses, and it appeared to be associated with prolonged bronchodilation and improved outcome.