Single dose intranasal administration of 220 micrograms of NASACORT in normal adult subjects and in adult patients with allergic rhinitis demonstrated low absorption of triamcinolone acetonide. The mean peak plasma concentration was approximately ng/mL (range to 1 ng/mL) and occurred at hours post dose. The mean plasma drug concentration was less than ng/mL at 12 hours and below the assay detection limit at 24 hours. The average terminal half life was hours. Dose proportionality was demonstrated in normal subjects and in patients following a single intranasal dose of 110 micrograms or 220 micrograms NASACORT. Following multiple doses in pediatric patients, plasma drug concentrations, AUC, Cmax and Tmax were similar to those values observed in adult patients.
The precise mechanism through which fluticasone propionate affects rhinitis symptoms is not known. Corticosteroids have been shown to have a wide range of effects on multiple cell types (., mast cells, eosinophils, neutrophils, macrophages, lymphocytes) and mediators (., histamine, eicosanoids, leukotrienes, cytokines) involved in inflammation. In 7 trials in adults, fluticasone propionate nasal spray has decreased nasal mucosal eosinophils in 66% of patients (35% for placebo) and basophils in 39% of patients (28% for placebo). The direct relationship of these findings to long-term symptom relief is not known.