PARTIAL INHIBITION OF THE EARLY AND LATE ASTHMATIC RESPONSE BY A SINGLE-DOSE OF SALMETEROL

The long-acting beta(2)-agonist salmeterol has been suggested to have other pharmacologic activities, that is, antiinflammatory capacities, in addition to its bronchodilator properties. We investigated the prot ective effect of 50 mu g salmeterol in a placebo-controlled study on h ouse dust mite-induced early- and late-phase reactions in 19 atopic as thmatic subjects. FEV(1) and methacholine airway reactivity (AR) were measured. Eosinophils and their activation markers in peripheral blood were counted as indirect parameters of inflammation. Corrections were made for confounding of bronchodilator effects by salmeterol and the spontaneous diurnal variation, using saline inhalation as a control. S almeterol completely inhibited the fall in FEV(1) up to 10 h after the house dust mite challenge. Nevertheless, after correction, a biphasic response was present in the salmeterol group. Salmeterol protected ag ainst the allergen-associated increase in AR 3 h af ter the challenge, but no protection was observed af ter 24 h. Salmeterol did not inhibi t the allergen-induced changes in total number of eosinophils and thei r activation markers in peripheral blood. These data suggest that a si ngle dose of salmeterol modifies allergen-induced airway responses, ab ove all by sustained bronchodilation.