A 4-week comparison of salmeterol and terbutaline in adult asthma.

This was a 4-week, open-label, parallel-group study designed to compare the efficacy and safety of the long-acting inhaled bronchodilator, salmeterol, with the established inhaled bronchodilator, terbutaline, in the treatment of patients with mild to moderate asthma. A total of 243 adult patients was randomized to receive treatment with either salmeterol 50 micrograms bd via a Diskhaler (Glaxo) inhaler (n = 121) or terbutaline 500 micrograms qds via a reservoir powder inhaler device (n = 122). Apart from all bronchodilator treatment which was withdrawn at the start of the run-in period and replaced by inhaled salbutamol to be used as required for symptom relief, all concurrent medications were kept constant throughout the study. Salmeterol produced a significantly greater increase in mean morning peak expiratory flow (PEF) than terbutaline (difference in adjusted means after treatment = 28 l/min; 95% CI = 19-37 l/min; P < 0.001). Likewise, the increase in mean evening PEF was significantly greater following treatment with salmeterol than with terbutaline (difference in adjusted means = 9 l/min; 95% CI = 0-17 l/min; P = 0.045). Salmeterol was associated with a significant reduction in diurnal variation in PEF by comparison with terbutaline (difference in adjusted means = -18 l/min; 95% CI = -24, -12 l/min; P < 0.001). Significant improvements with salmeterol by comparison with terbutaline were also observed in daytime and night-time asthma scores, percentage of symptom-free days and nights, use of additional inhaled bronchodilator, and percentage of days and nights when no additional inhaled bronchodilator was needed.(ABSTRACT TRUNCATED AT 250 WORDS)