fluticasone/salmeterol contains fluticasone propionate a synthetic corticosteroid and salmeterol a selective, long-acting, beta-adrenergic receptor agonist. fluticasone works as a potent anti-inflammatory agent, inhibiting multiple cell types such as mast cells, eosinophils, basophils, lymphocytes, macrophages, and neutrophils all of which contribute to inflammation, a large component in the pathogenesis of asthma. salmeterol works by stimulating intracellular adenyl cyclase which acts as a catalyst in the production of cyclic amp. increased cyclic amp levels lead to a relaxation of bronchial smooth muscles. additionally, cyclic amp inhibits the release of mediators of immediate hypersensitivity.