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. |
| Molecular Weight | 521.4 |
| Action Class | Topical/Inhaled Corticosteroid |
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 | Limited data; animal studies show teratogenic effects at high doses. Use only if potential benefit justifies risk to fetus. Avoid first trimester unless essential. |
| 2nd trimester | Use caution; prolonged or high-dose use may cause fetal growth restriction. Monitor for adrenal suppression in newborn if used near term. |
| 3rd trimester | Avoid prolonged use; risk of fetal hypothalamic-pituitary-adrenal axis suppression. Use lowest effective dose. |
Clinical note
Strong CYP3A4 inhibitors may increase systemic exposure Systemic absorption can occur with extensive use.
| Placental transfer | Mometasone furoate crosses placenta; degree unknown in humans. In animals, placental transfer observed with potential for fetal effects at high doses. |
| Breastfeeding | Excretion into human milk unknown; systemic absorption minimal after topical use. Use with caution, especially on large areas or occluded skin. Monitor infant for growth retardation or adrenal suppression. |
■ FDA Black Box Warning
None.
| Common Effects | Diarrhea Stomach pain |
| Serious Effects | Adrenal suppression, Cushing's syndrome, Growth retardation in children, Osteoporosis, Glaucoma and cataracts, Immunosuppression with increased infection risk, Hypersensitivity reactions including anaphylaxis |
Hypersensitivity to mometasone furoate or any componentUntreated bacterial, fungal, or viral infectionsRosaceaPerioral dermatitis
| 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 |
Loading safety data…
| Lactation Rating | L3 (Moderately Safe) |
| 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. |
| 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. |
| Food/Dietary | No significant food interactions are known for mometasone furoate. However, for nasal or inhaled formulations, avoid concurrent use of grapefruit juice as it may theoretically increase systemic levels via CYP3A4 inhibition, though clinical relevance is minimal. |
| Clinical Pearls | Mometasone furoate is a potent topical corticosteroid classified as group 4 (medium potency) or group 5 (higher potency in ointment form) depending on formulation. For nasal sprays, counsel patients to avoid spraying directly onto nasal septum to prevent perforation. In dermatological use, limit continuous application to 2 weeks on face or intertriginous areas to avoid atrophy. In asthma, mometasone via dry powder inhaler (DPI) requires high inspiratory flow; ensure proper technique. Reassess adrenal suppression risk with long-term use, especially in children. |
| Patient Advice | Apply a thin layer only to affected skin; do not use on face, groin, or under diapers unless directed by your doctor. · Do not cover treated areas with bandages or wrappings unless instructed, as this increases absorption and side effects. · For nasal spray: shake well before use, prime with 10 sprays if new or 1 spray if used in last week, and tilt head slightly forward to spray away from septum. · Rinse mouth after using the inhaler to prevent oral thrush; do not swallow the rinse water. · Avoid abrupt discontinuation after prolonged use; taper as directed to prevent rebound inflammation. · Store at room temperature away from moisture and heat; do not freeze. |