MOMETASONE FUROATE
Clinical safety rating: safe
Animal studies have demonstrated safety
Mometasone furoate is a corticosteroid with anti-inflammatory, antipruritic, and vasoconstrictive properties. It binds to the glucocorticoid receptor, leading to inhibition of phospholipase A2, reduced arachidonic acid release, and decreased synthesis of prostaglandins and leukotrienes. It also suppresses cytokines, chemokines, and adhesion molecules involved in inflammation.
| Metabolism | Mometasone furoate is extensively metabolized in the liver via cytochrome P450 3A4 (CYP3A4) to various metabolites. The major metabolite is 6β-hydroxy-mometasone furoate. Systemic exposure is minimal due to extensive first-pass metabolism and low oral bioavailability. |
| Excretion | Mometasone furoate is extensively metabolized in the liver; less than 1% of the dose is excreted unchanged in urine. The metabolites are primarily excreted in feces (~74%) via biliary elimination, with renal excretion accounting for approximately 8–10%. |
| Half-life | The terminal elimination half-life is approximately 5.8 hours (range 4.5–7.5 hours) following intravenous administration; after intranasal or inhalation use, the effective half-life supporting once-daily dosing is derived from receptor binding and local tissue retention. |
| Protein binding | Mometasone furoate is 98–99% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | The volume of distribution at steady state is approximately 332 L (range 152–552 L; ~4.7 L/kg for a 70 kg adult), indicating extensive tissue distribution and partitioning into tissues. |
| Bioavailability | Intranasal: Systemic bioavailability is <1% (0.1–0.7%) due to low absorption and high first-pass metabolism. Inhaled: Absolute bioavailability is low (<1%) due to pulmonary deposition and extensive hepatic first-pass metabolism. Topical: Percutaneous absorption is minimal (<0.1%) with intact skin; slightly higher in damaged skin. |
| Onset of Action | Intranasal: Onset of action (reduction in nasal symptoms) is observed within 12 hours, with maximum benefit achieved after several days. Inhaled: Onset of bronchodilatory effect is not applicable; clinical improvement in asthma control occurs within 1–2 weeks. Topical: Onset of anti-inflammatory effect is within a few days to weeks depending on lesion type. |
| Duration of Action | Intranasal: Provides 24-hour symptomatic relief with once-daily dosing due to prolonged receptor occupancy. Inhaled: Duration of effect supports once-daily dosing for maintenance therapy. Topical: Duration varies by formulation; typically applied once daily, with therapeutic effect persisting for 24 hours. |
Inhaled: 110-880 mcg twice daily; Intranasal: 2 sprays (50 mcg/spray) per nostril once daily; Topical: Apply thin film to affected area once daily.
| Dosage form | SPRAY, METERED |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment recommended for hepatic impairment; use with caution in severe impairment. |
| Pediatric use | Inhaled: 110-220 mcg twice daily for ages 12 and older; Intranasal: 1 spray (50 mcg) per nostril once daily for ages 2-11; Topical: Apply once daily for ages 2 and older. |
| Geriatric use | No specific dose adjustment; use lowest effective dose due to potential for increased systemic effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Strong CYP3A4 inhibitors may increase systemic exposure Systemic absorption can occur with extensive use.
| Breastfeeding | Minimal excretion into breast milk; M/P ratio not established. Use with caution, as systemic exposure in infants is low but potential for adrenal suppression exists. Not expected to cause adverse effects at maternal doses up to 400 mcg/day. |
| Teratogenic Risk | Insufficient human data; animal studies show no teratogenicity at clinically relevant doses. Corticosteroids are generally associated with a small increased risk of oral clefts when used in the first trimester, but risk is low. Avoid high doses if possible. |
■ FDA Black Box Warning
None.
| Common Effects | Diarrhea Stomach pain |
| Serious Effects |
["Hypersensitivity to mometasone furoate or any component of the formulation","Untreated systemic infections (e.g., fungal, bacterial, viral, parasitic)","Primary treatment of status asthmaticus or acute bronchospasm (inhaled form)","Intranasal use in patients with recent nasal septal ulcers, nasal surgery, or nasal trauma until healing occurs"]
| Precautions | ["Hypothalamic-pituitary-adrenal (HPA) axis suppression, especially with prolonged use, large areas of application, or occlusive dressings (topical)","Systemic corticosteroid effects such as Cushing's syndrome, hyperglycemia, and growth retardation in children (topical and intranasal)","Oropharyngeal candidiasis and hoarseness with inhaled form; may require antifungal therapy and mouth rinsing after use","Reduced bone mineral density with long-term use (inhaled)","Possible increased risk of infections (e.g., chickenpox, measles) due to immunosuppression","Avoid use in patients with untreated fungal, bacterial, or viral infections","Nasal spray: epistaxis, nasal septal perforation (rare); monitor for glaucoma and cataracts with prolonged use","Inhaled form: paradoxical bronchospasm; discontinue immediately if occurs"] |
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| Fetal Monitoring |
| Monitor for potential fetal growth restriction if used chronically at high doses. Monitor maternal adrenal function if long-term high-dose therapy is required. Assess for signs of maternal infection. |
| Fertility Effects | No known adverse effects on fertility in human studies. In animal studies, no impairment of fertility at systemic exposures comparable to clinical doses. |