Background: Salmeterol is the first long-acting inhaled bronchodilator available in the United States. This paper summarizes the combined results of the two pivotal US studies evaluating the efficacy of this beta 2-agonist in the maintenance treatment of asthma.
Methods: Salmeterol (42 micrograms twice daily) was compared with the short-acting beta 2-agonist albuterol (180 micrograms four times daily) in two double-blind, randomized studies involving 556 patients with mild-to-moderate asthma. All patients could use supplemental inhaled albuterol as needed for breakthrough symptoms, and patients were allowed to continue to use inhaled corticosteroids during the study.
Results: Salmeterol, 42 micrograms bid, was more effective than albuterol, 180 micrograms qid, or placebo in maintaining bronchodilation, as measured by FEV1 over 12-hour periods and morning and evening peak expiratory flow rates. Patients who received salmeterol also experienced significantly greater increases in the number of days without asthma symptoms and the percentage of nights without awakenings compared with either the albuterol or placebo group. There was no difference between patients who received concomitant inhaled corticosteroids and those who did not with respect to pulmonary-function measurements or improvements in symptoms. There was no loss of asthma control with salmeterol over the 12-week period.
Conclusions: Salmeterol, 42 micrograms twice daily, was more effective than albuterol, 180 micrograms four times daily, or placebo (plus as-needed albuterol) in improving pulmonary function and controlling asthma symptoms.