Efficacy and safety of salmeterol in childhood asthma

Abstract

In children with asthma, twice daily administration of salmeterol 25 μg, salmeterol 50 μg and salbutamol 200 μg were compared in two, 3-month, double-blind, parallel group studies, one using metered dose inhalers (MDIs), the other using dry powder inhalers (Diskhaler, DPIs). Both studies were continued for a further 9 months during which time exacerbation rates, lung function at the clinic and adverse events were monitored. Similarities in design and methodology of the two studies justified a combined analysis. Eight hundred and forty-seven asthmatic children aged between 4 and 16 (mean 10.1) years, requiring inhaled beta₂-agonist treatment were randomised to treatment. After a 2 week run-in when all bronchodilator therapy was withdrawn, 279 patients received salmeterol 25 μg bd, 290 patients salmeterol 50 μg bd and 278 patients salbutamol 200 μg bd. After 3 months' treatment the change from baseline in daily morning and evening peak expiratory flow (PEF) was significantly greater with salmeterol 50 μg bd than with salbutamol 200 μg bd (P<0.001). Salmeterol 50 μg bd was also significantly better than salmeterol 25 μg bd at improving mean morning PEF (P=0.017) but both treatments had a similar effect on evening PEF. Analysis of variance showed an interaction between baseline PEF less than 100% predicted normal value and treatment outcome. Analysis of this sub-set of patients with lower lung function revealed similar results to the total population although the improvements in PEF from baseline were greater. Data from both studies, showed that the improvement in lung function was maintained throughout 12 months' treatment. Patients receiving salmeterol 50 μg bd had significantly more symptom-free nights (P<0.01) and a higher percentage of rescue bronchodilator-free days (P=0.01). The incidence of asthma exacerbations was evenly distributed between the three treatment groups and there was no evidence of any change in the rate of occurrence of exacerbations over the 12 month period. Adverse events were no different across treatment groups or across age groups and were primarily related to the patients' disease state.