Background: The purpose of this study was to test the contribution of aminophylline in improving peak expiratory flow rate (PEFR) during emergency department treatment of acute asthma when metaproterenol sulfate and steroid therapy are also provided.
Methods: In a prospective, randomized, double-blind, and placebo-controlled trial at a municipal hospital emergency department, 44 patients with acute asthma, aged 18 to 45 years, with theophylline levels below 28 mumol/L, who had failed to achieve a PEFR of 40% predicted after one nebulized metaproterenol treatment, were recruited. An aminophylline or placebo loading dose and maintenance infusion were administered. All patients received hourly nebulized metaproterenol and initial methylprednisolone sodium succinate. The PEFR was measured hourly for 5 hours. Two-factor repeated-measures analysis of variance of improvement in PEFR ([final-initial PEFR]/predicted PEFR) was assessed.
Results: There was no difference in improvement of PEFR at any hour between the treatment and placebo groups. After 5 hours, the difference in improvement ratio was 0.40 (aminophylline) vs 0.36 (placebo) (P = .30; n = 22 in each group). The treatment group suffered more tremor, nausea or vomiting, and palpitations (P < .05).
Conclusion: In the emergency department setting, aminophylline contributes no significant improvement in PEFR when beta 2-agonists and corticosteroids are being provided, while causing more side effects.