Frequency of inhaled metaproterenol in the treatment of acute asthma exacerbation.

Acute asthma exacerbations are common complaints in patients who present to the emergency department. A prospective, double-blinded study was designed to evaluate how frequency of dosing of an inhaled beta-agonist, metaproterenol (Alupent inhalation solution) would affect patient response, length of stay in the ED, and admission rates. Forty-one patients initially received a 0.3-mL dose of nebulized metaproterenol followed by two additional doses of either metaproterenol or saline every 20 minutes. While there was no difference in response (forced expiratory volume in one second) in patients at 30 minutes after their arrival, there was an improved response in the metaproterenol group at 60 and 120 minutes. The length of stay in the ED was approximately the same for both groups. There was no significant difference in admission rates. No increase in undesirable side effects (eg, nausea, tremor, palpitations) was seen in the metaproterenol-treated group. Frequent dosing of metaproterenol is useful in asthmatics having acute exacerbations and leads to rapid improvement without an increase in toxicity.