Nasonex Mechanism of Action

Mometasone furoate is a topical glucocorticosteroid with local anti-inflammatory properties at doses that are not systemically active.
It is likely that much of the mechanism for the antiallergic and anti-inflammatory effects of mometasone furoate lies in its ability to inhibit the release of mediators of allergic reactions. Mometasone furoate significantly inhibits the release of leukotrienes from leucocytes of allergic patients. In cell culture, mometasone furoate demonstrated potency in inhibition of synthesis and release of IL-l, IL-5, IL-6 and TNFα. It is also a potent inhibitor of leukotriene production. In addition, it is an inhibitor of the production of the Th 2 cytokines IL-4 and IL-5, from human CD4+ T-cells. In studies utilizing nasal antigen challenge, Nasonex aqueous nasal spray has shown anti-inflammatory activity in both the early- and late-phase allergic responses. This has been demonstrated by decreases (vs placebo) in histamine and eosinophil activity and reductions (vs baseline) in eosinophils, neutrophils and epithelial cell adhesion proteins. In patients with seasonal allergic rhinitis, Nasonex aqueous nasal spray demonstrated a clinically significant onset of action within 12 hrs after the 1st dose.
Pharmacokinetics: Mometasone furoate, administered as a nasal spray, has negligible (≤0.1%) systemic bioavailability and is generally undetectable in plasma, despite the use of sensitive assay with a lower quantitation limit of 50 pg/mL; thus, there are no relevant pharmacokinetic data for this dosage form. Mometasone furoate suspension is very poorly absorbed from the gastrointestinal tract, and the small amount that may be swallowed and absorbed undergoes extensive first-pass hepatic metabolism prior to excretion in urine and bile.