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.
The recommended dose is one or two sprays in each nostril once daily. Before use of the nasal spray, the nose should be blown gently, and the inhaler or spray should be shaken. The head should be tilted backwards, with the nozzle inserted into one nostril, the opening of the nozzle toward the swollen area. The other nostril should be closed. and the spray or inhaler activated while breathing in through the nose and out through the mouth. The inhaler or spray should be cleaned daily. The canister should be removed from the inhaler, rinsing the cap, nosepiece, and the inhaler with warm water and then drying them thoroughly.
In a pharmacokinetic study comparing flunisolide nasal solution (flunisolide nasal spray .025%) (29 mcg per spray) with flunisolide nasal solution (flunisolide nasal spray .025%) (25 mcg per spray), the original formulation, the two formulations were not bioequivalent. The total absorption of flunisolide nasal solution (29 mcg per spray) was 25% less than that of flunisolide nasal solution (25 mcg per spray), and the peak plasma concentration was 30% lower. The clinical significance of these differences is likely to be small, particularly since clinical efficacy is attributable to a local effect on nasal mucosa (see Pharmacodynamics ).