Mometasone furoate (Nasonex (R)) is a high-potency intranasal corticosteroid available for the treatment and/or prophylaxis of the nasal symptoms of seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR). In the EU, it is approved for use in patients aged >= 6 years and, in the US, it is approved as a treatment in patients aged :2 years and as prophylaxis in those >= 12 years of age. Extensive experience in both clinical trials and the clinical practice setting has firmly established the efficacy and good tolerability profile of intranasal mometasone furoate in children and adults with PAR or SAR. Thus, intranasal mometasone furoate is a useful first-line option for the treatment and prophylactic management of these conditions, including in children as young as 2 years of age in some countries and 6 years of age in others. Pharmacological Properties Intranasal mometasone furoate is a synthetic glucocorticosteroid that inhibits the early- and late-phase allergic response. It acts by preventing the influx of inflammatory cells into the nasal mucosa, and inhibits the expression of soluble mediators Such as histamine, interleukin (IL)-1, IL-4, IL-5, IL-6, IL-8, interferon-gamma, leukotrienes and tumour necrosis factor-alpha. Intranasal mometasone furoate hits no suppressive activity on hypothalamic-pituitary-adrenal axis function, nor on growth, in volunteers or children and adults with allergic rhinitis when administered at recommended therapeutic dosages. No atrophy or alterations in epithelial thickness were observed in patients undergoing nasal biopsies before and after I year of treatment with intranasal mometasone furoate. Systemic absorption of mometasone furoate after intranasal administration is negligible and has been estimated to be < 1%. Mometasone furoate is approximate to 99% protein bound at clinically relevant plasma concentrations. Any part of the intranasal dose swallowed and absorbed undergoes extensive first-pass metabolism to multiple metabolites, which are excreted predominantly in the bile and, to a lesser extent, in the urine. Therapeutic Efficacy Intranasal mometasone furoate improved the nasal symptoms of SAR and PAR to a significantly greater extent than placebo as determined by reductions from baseline in patient- and/or investigator-assessed total nasal symptom scores (TNSS). There were no significant differences between mometasone furoate and active comparators (budesonide, beclomethasone dipropionate, fluticasone propionate) in this regard in well designed clinical trials. Tolerability Intranasal mometasone furoate also improved individual nasal symptom scores, non-nasal symptom scores and ocular symptoms, with significantly greater effects than placebo at. the majority of timepoints. Overall assessments of treatment response (patient- or investigator-rated) also demonstrated the significant therapeutic benefits of mometasone furoate (and other active treatments) over placebo.