Effect of Salmeterol Is Independent of Previously Inhaled Salbutamol: A Clinical Controlled Study

Byline: J. T. R. Wilcke (1), E. T. Iversen (1), A. Kok-Jensen (1) Keywords: Key words: Interaction salmeterol-salbutamol--Long acting/short acting [beta]2-agonists--Asthma. Abstract: The objective of this study was to examine the bronchodilating effect of an inhaled long acting [beta].sub.2-agonist (salmeterol) after a high dose of an inhaled short acting [beta].sub.2-agonist (salbutamol) in asthma patients. We used a randomized double-blind, placebo-controlled, crossover design, studying seven subjects with moderate asthma, treated with inhaled steroids and highly reversible to salbutamol and salmeterol. 1.5 h after salmeterol inhalation, the mean difference in FEV.sub.1 between salbutamol and placebo pretreatment days was 6.31% and ranged from 0.02 to 1.05%, 2.5--10.5 h after salmeterol inhalation. We concluded that the effect measured as the duration of bronchodilation of salmeterol is not decreased by previously inhaled salbutamol. We only found a trend toward an additive effect of combining salbutamol and salmeterol, probably because the high dose of salbutamol did not give room for further improvement in FEV.sub.1. In accordance with other clinical studies we were unable to demonstrate any clinical implications of the salmeterol partial [beta].sub.2-antagonism known from animal and in vitro studies. Author Affiliation: (1) Department of Respiratory Medicine P, Bispebjerg Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark, DK Article note: Accepted for publication: 25 June 1997