mometasone furoate (inhaled)
Brand: Asmanex Twisthaler, Asmanex HFA
Prototype: fluticasone propionate
Drug Class: inhaled corticosteroid (ICS)
Drug Family: corticosteroid
Subclass: synthetic glucocorticoid
Organ Systems: respiratory
Mechanism of Action
Potent synthetic glucocorticoid with high glucocorticoid receptor affinity; suppresses airway eosinophilic inflammation, decreases IgE synthesis and mast cell mediator release, reduces cytokine production, and decreases airway hyperresponsiveness — mechanisms underlying long-term asthma control.
glucocorticoid receptor (GR)eosinophilsmast cellsTh2 lymphocytes
Indications
- persistent asthma (maintenance therapy in patients aged 4 years and older)
- asthma maintenance and prevention of symptoms
Contraindications
- acute asthma exacerbations or status asthmaticus
- hypersensitivity to mometasone
Adverse Effects
Common
- oropharyngeal candidiasis
- dysphonia
- headache
- nasopharyngitis
- sinusitis
Serious
- adrenal suppression (high dose, prolonged use)
- osteoporosis
- cataracts and glaucoma
- growth suppression in children
Pharmacokinetics (ADME)
| Absorption | inhaled; systemic bioavailability approximately 11%; minimal first-pass effect (oral bioavailability of swallowed portion <1%) |
| Distribution | Vd approximately 152 L; 98-99% protein bound |
| Metabolism | hepatic CYP3A4; multiple metabolites all less potent than parent drug |
| Excretion | fecal (~74%) and renal (~8%) |
| Half-life | approximately 5 hours |
| Onset | anti-inflammatory benefit within 1-2 weeks; maximal benefit at 1-2 months |
| Peak | 1-2.5 hours |
| Duration | 24 hours; can be dosed once or twice daily depending on disease severity |
| Protein Binding | 98-99% |
| Vd | approximately 152 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir) | increase mometasone systemic exposure; adrenal suppression and Cushing syndrome risk | major |
| other ICS or systemic corticosteroids | additive adrenal suppression at high cumulative doses | moderate |
Nursing Considerations
- The Twisthaler device requires twisting and clicking to load the dose; instruct patients to exhale fully, inhale rapidly and deeply, hold breath 10 seconds, then exhale — rinse mouth with water afterward.
- Monitor for signs of systemic corticosteroid toxicity in patients taking higher doses (400 mcg/day or more): moon face, easy bruising, striae, weight gain, hypertension, hyperglycemia.
- In children, mometasone is approved for ages 4 and older; monitor height at each visit and counsel families that growth velocity may be reduced with long-term ICS use — weigh benefit of asthma control against growth risk.
- Mometasone can be dosed once daily for mild-to-moderate persistent asthma; twice-daily dosing is used for more severe disease — confirm the prescribed regimen at each visit.
Clinical Pearls
- Mometasone furoate has one of the lowest oral bioavailabilities of all ICS (less than 1%), meaning that the portion of drug swallowed is almost entirely inactive — a pharmacological advantage contributing to low systemic exposure relative to inhaled effect.
- Mometasone is available in both inhaled (Asmanex) and intranasal (Nasonex) formulations; the doses and devices are different — nurses and pharmacists must verify the intended route when reviewing prescriptions to avoid confusion.
Safety Profile
Pregnancy use-with-caution
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.