Salmeterol xinafoate in the treatment of mild to moderate asthma in primary care. UK Study Group.

Abstract

Clinical studies of inhaled salmeterol xinafoate have been conducted mainly in moderately to severely affected asthmatic subjects in hospital settings. This study was conducted to investigate the effectiveness of this drug in patients with milder asthma in primary care. A multicentre, double blind, randomised, parallel group comparison of salmeterol xinafoate in a dose of 50 micrograms twice daily with placebo, both administered from a four-place dry powder inhaler (Diskhaler), was performed over six weeks in United Kingdom general practices. A total of 427 asthmatic patients aged 18 years or older were randomised to receive salmeterol or placebo in a 2:1 ratio. Of the total randomised population, 247 patients were previously on short acting bronchodilators alone whilst 180 patients were concurrently receiving up to 400 micrograms inhaled corticosteroid. Mean morning peak expiratory flow rose more in the salmeterol group than in the placebo group (treatment difference 17 l/min, 95% confidence interval 9 to 26 l/min) but there was a smaller, non-significant difference in mean evening peak expiratory flow. Improvements occurred in the salmeterol-treated group compared with placebo for wheeze, shortness of breath, undisturbed nights, and relief medication use, irrespective of concomitant inhaled corticosteroid use. In addition, improvement in activity restriction was seen in the salmeterol group compared with placebo in the subgroup receiving only bronchodilator. Salmeterol is effective and well tolerated in the short term in mildly asthmatic adult patients irrespective of concomitant use of inhaled corticosteroid therapy.