ACUTE BRONCHODILATORY EFFECT OF SALMETEROL ON METHACHOLINE-INDUCED BRONCHOCONSTRICTION IN CHILDHOOD ASTHMA

A review of the literature highlights the need for research, particula rly on the acute bronchodilatory effect of salmeterol on bronchoconstr iction in the pediatric age group. The present study attempted to eval uate the acute bronchodilatory effect of salmeterol on methacholine-in duced bronchoconstriction in childhood asthma and to compare it with t he effect of salbutamol. Forty-four asymptomatic children with mild-to -moderate asthma (23 boys and 21 girls: aged 7-17 years) were studied. At the beginning, the baseline forced expiratory volume in 1 s (FEV1) was measured, and the methacholine challenge was performed by doublin g the dose to determine PC20 (provocative concentration of inhaled met hacholine required to reduce FEV1 by 20%). At the same time, the trans cutaneous arterial oxygen saturation (SaO2) was also measured. Each su bject inhaled a single dose of 25 mu g salmeterol (n: 23, group I) or 100 mu g salbutamol (n: 21, group II) following the SaO2 measurement. The same measurements (FEV1, SaO2) were repeated 5 and 20 min after th e inhalation. After inhalation of salmeterol or salbutamol, the differ ences between the values of FEV1 and SaO2 after 5 and 20 min were insi gnificant in both group I and group II (P>0.05), although there was a significant improvement in both FEV1 and SaO2 after 5 and 20 min (P<0. 005). From these findings it was concluded that salmeterol can be cons idered as effective as salbutamol on methacholine-induced bronchoconst riction.