A comparative study of the aerosolized bronchodilators, isoproterenol, metaproterenol and terbutaline in asthma.

Twenty-one patients with asthma were studied in a double-blind manner for the effects of three aerosolized bronchodilators (isoproterenol, metaproterenol and terbutaline) on small, large and mixed airways, blood pressure, heart rate and various blood chemistries. Favorable responses were measured within 30 seconds for each drug. However, only the newer, selective beta-2 agonists, metaproterenol and terbutaline, produced significantly prolonged action upon small as well as large airways and lung volumes. Of the two, terbutaline tended to have an earlier and higher peak activity and longer duration of action, especially on large airways. Such prolonged activity by the newer agents suggests a safer and more effective alternative to isoproterenol inhalation.