The National Asthma Education and Prevention Program published the first set of national guidelines for the emergency treatment of patients with asthma in 1991. The current recommendation for treating acute exacerbation of asthma is 2.5 to 5 mg of albuterol inhalation therapy every 20 minutes for the first hour. However, there are few studies to support this recommendation. Cydulka and colleagues compared the relief of airway obstruction obtained by using a single 7.5-mg dose of albuterol with three sequential doses of 2.5-mg albuterol 20 minutes apart.
The randomized clinical trial was conducted at an urban emergency department. Adult patients who presented with acute asthma as defined by the American Thoracic Society criteria were enrolled in the study. To participate, the patients had to have a forced expiratory volume in one second (FEV1) of 75 percent or less of predicted value. The participants were then randomized to receive 7.5 mg of nebulized albuterol in a single dose or 2.5 mg every 20 minutes for three treatments. Spirometry was performed 30, 60, and 100 minutes after treatment. The primary outcome measurement was the change in the FEV1 level over time. Secondary outcome measures included the number of patients admitted to the hospital after treatment and the incidence of side effects.
The 94 patients who participated in the study were randomly divided into the two treatment groups. The amount of pulmonary obstruction was severe, with the FEV1 for both groups at about 46 percent of predicted. The single-dose and multidose treatment groups showed similar improvement in FEV1 levels, and there was no significant difference in that improvement when comparing the two groups. The hospitalization rate was similar in both treatment groups. The single-dose group reported more side effects than the multidose group (40 versus 22 percent). This was a trend, but it did not reach statistical significance (P = 0.06).
The authors conclude that a single dose of 7.5 mg of albuterol delivered by nebulizer is equivalent to three sequential doses of 2.5-mg albuterol delivered by nebulizer in the treatment of moderate to severe acute asthma. They add that the single-dose scheme would reduce the likelihood that a subsequent dose could be delayed or missed.