Inhaled salmeterol - A review of its efficacy in chronic obstructive pulmonary disease

Inhaled salmeterol is a long-acting, selective beta2-adrenoceptor agonist bronchodilator. The drug has been compared with placebo, ipratropium bromide and oral theophylline in patients with chronic obstructive pulmonary disease (COPD) in randomised, clinical trials. Inhaled salmeterol 50 mug twice daily produced significant improvement in forced expiratory volume in 1 second (FEV1), equivalent to that obtained with inhaled ipratropium bromide 40 mug 4 times daily and greater than that obtained with placebo or oral theophylline in randomised trials. Use of as-needed salbutamol (albuterol) was significantly reduced during treatment with inhaled salmeterol or ipratropium bromide compared with placebo or oral theophylline. The time to first COPD exacerbation was significantly longer during 12 weeks of treatment with inhaled salmeterol 50 mug twice daily than ipratropium bromide 40 mug 4 times daily. Compared with baseline and placebo, patients treated for 16 weeks with salmeterol 50 mug (but not 100 mug) twice daily reported significant improvement in total St George's Respiratory Questionnaire (SGRQ) scores. Similarly, more patients treated with inhaled salmeterol 50 mug twice daily or ipratropium bromide 40 mug 4 times daily experienced an increase of greater than or equal to 10 points in Chronic Respiratory Disease Questionnaire (CRQ) scores, the minimum clinically significant increment. Compared with placebo, inhaled salmeterol 50 mug twice daily alone, or concurrent with ipratropium bromide 40 mug 4 times daily improved lung function and reduced symptoms in patients with stable COPD in a 12-week, randomised, double-blind study. Clinically meaningful improvement in CRQ scores was documented in significantly more patients treated with the combination of the 2 drugs than either salmeterol monotherapy or placebo. Inhaled salmeterol 50 mug twice daily plus oral theophylline had additive effects on lung function, increased the proportion of symptom-free days and decreased requirements for as-needed salbutamol compared with either agent alone according to a pooled analysis of 2 multicentre, randomised, double-blind studies. Conclusion: When used at the optimal dosage, 50 mug twice daily, salmeterol provides symptomatic relief and improves lung function and health-related quality of life in patients with COPD. Available evidence suggests that the drug is as effective as ipratropium bromide and more effective than oral theophylline in patients with COPD. Moreover salmeterol has additive effects when used in combination with inhaled ipratropium bromide or oral theophylline. These qualities make the drug suitable for first-line use in patients with COPD who require regular bronchodilator therapy to manage symptoms.