<p>Fluticasone propionate is a synthetic, trifluorinated glucocorticoid&nbsp;with potent anti-inflammatory activity.&nbsp;In vitro assays using human lung cytosol preparations have established fluticasone propionate as a human glucocorticoid receptor&nbsp;agonist&nbsp;with an&nbsp;affinity&nbsp;18 times greater than dexamethasone, almost twice that of beclomethasone-17-monopropionate (BMP), the active metabolite of beclomethasone dipropionate, and over 3 times that of budesonide. Data from the McKenzie vasoconstrictor&nbsp;assay&nbsp;in man are consistent with these results.<br />
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The precise mechanisms of glucocorticoid action in&nbsp;asthma&nbsp;are unknown.&nbsp;Inflammation&nbsp;is recognized as an important component in the&nbsp;pathogenesis&nbsp;of asthma. Glucocorticoids have been shown to inhibit multiple&nbsp;cell&nbsp;types (e.g., mast cells, eosinophils, basophils, lymphocytes, macrophages, and neutrophils) and mediator production or secretion (e.g.,&nbsp;histamine, eicosanoids, leukotrienes, and cytokines) involved in the&nbsp;asthmatic response. These anti-inflammatory actions of glucocorticoids may contribute to their efficacy in asthma.<br />
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Though highly effective for the treatment of asthma, glucocorticoids do not affect asthma symptoms immediately. However, improvement following inhaled administration of fluticasone propionate can occur within 24 hours of beginning treatment, although maximum benefit may not be achieved for 1 to 2 weeks or longer after starting treatment. When glucocorticoids are discontinued, asthma stability may persist for several days or longer.</p>