Emergency therapy of asthma: comparison of the acute effects of parenteral and inhaled sympathomimetics and infused aminophylline.

Forty-eight patients who presented with acute episodes of asthma were randomized to treatment with subcutaneously administered epinephrine, inhaled isoproterenol, or intravenously administered aminophylline. The patients' couses were followed clinically and with spirometry. Although there were no significant differences between the groups before treatment for any measured variable, at the end of 1 hour, the mean improvement inforced expiratory volume in one second (FEV1) was significantly greater for patients treated with epinephrine (0.76 L) or nebulized isoproterenol (0.79 L) than for those given aminophylline (0.23 L). Similarly, the mean duration of therapy required before discharge from the emergency room was significantly longer for patients receiving aminophylline (5.4 h) than for patients treated with either epinephrine (3.5 h) or isisoproeternol (3.0 h). There was no significant differences between the effects of the 2 beta agonists. These results demonstrated that short-acting sympathomimtic agents produce more rapid and potent bronchodilatation in acutely ill asthmatics than that provided by intravenously administered methylxanthines, and that there are no disadvantages to using an inhaled beta agonist rather than one administered parenterally.