Aerosol vs injected epinephrine in acute asthma

Twenty-five patients with acute asthma were randomized prospectively into one of two double-blind treatment regimens: regimen 1 consisted of subcutaneous epinephrine combined with aerosol placebo; regimen 2 consisted of aerosol epinephrine with injected placebo. In patients with severe airway obstruction (peak expiratory flow rate ≤ 120, or ≤ 25% of predicted normal), parenteral epinephrine was superior to aerosol (P < 0.005) at the end of one hour. However, in patients with mild to moderate asthma (PEFR>120), injected and inhaled epinephrine were of equal efficacy, with the aerosol producing fewer side effects (P < 0.001).