ASMANEX TWISTHALER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ASMANEX TWISTHALER (ASMANEX TWISTHALER).
Corticosteroid that binds to the glucocorticoid receptor, leading to inhibition of inflammatory mediators (e.g., cytokines, chemokines, adhesion molecules) and suppression of inflammatory cell migration and activation in the airways.
| Metabolism | Hepatic metabolism via cytochrome P450 3A4 (CYP3A4) to inactive metabolites. |
| Excretion | Following oral inhalation, the absorbed fraction of mometasone furoate is extensively metabolized in the liver via CYP3A4. Unchanged drug and metabolites are excreted primarily in the feces via biliary elimination (approximately 74% of a single oral dose) and to a minor extent in the urine (approximately 8%). For inhaled doses, renal excretion of unchanged drug is negligible (<1% of administered dose). |
| Half-life | The terminal elimination half-life of mometasone furoate following inhalation via ASMANEX TWISTHALER is approximately 5 hours (range 4–6 hours) in patients with asthma. This relatively short half-life supports twice-daily or once-daily dosing with sustained clinical effect due to prolonged local retention in the lungs. |
| Protein binding | Mometasone furoate is 98–99% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Volume of distribution at steady state (Vdss) is approximately 332 L (range 224–440 L) after intravenous administration, corresponding to approximately 4.8 L/kg for a 70 kg individual. High Vd indicates extensive tissue distribution and high lipophilicity. |
| Bioavailability | Absolute bioavailability of mometasone furoate via inhalation is less than 1% due to efficient first-pass metabolism. Oral bioavailability from the swallowed fraction is also <1% due to extensive hepatic metabolism. Systemic exposure is primarily from the absorbed pulmonary fraction. |
| Onset of Action | Onset of clinical effect (improvement in FEV1) occurs within 1–2 weeks of regular twice-daily dosing. Maximal effect may take 2–4 weeks to achieve. No immediate bronchodilator effect is observed; onset is delayed due to corticosteroid mechanism of action. |
| Duration of Action | Duration of action supports twice-daily (200–400 mcg twice daily) or once-daily (400 mcg once daily) dosing in asthma. The clinical effect persists for at least 12 hours after a single dose, with sustained symptom control over 24 hours with once-daily dosing. Duration is dose-dependent and requires regular administration. |
| Molecular Weight | 588.7 |
| Action Class | Inhaled corticosteroid (ICS) |
Inhalation: 1-2 inhalations twice daily (morning and evening). Typical adult dose: 200-400 mcg twice daily. Maximum: 800 mcg/day.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment required for renal impairment. Data not sufficient for GFR-based modifications. |
| Liver impairment | No specific dose adjustment recommended. Use with caution in severe hepatic impairment (Child-Pugh C) due to limited data. |
| Pediatric use | Ages 12-17: 200 mcg twice daily. Ages 6-11: 100 mcg twice daily. Maximum: 200 mcg twice daily. Not recommended under 6 years. |
| Geriatric use | No specific adjustment. Use lowest effective dose due to potential for decreased renal function and increased systemic exposure. Monitor for adverse effects. |
| 1st trimester | Insufficient human data; animal studies show no teratogenicity at inhaled doses. Use only if benefit outweighs risk. |
| 2nd trimester | Insufficient human data; no known fetal harm. Use only if benefit outweighs risk. |
| 3rd trimester | Insufficient human data; no known fetal harm. Use only if benefit outweighs risk. |
Clinical note
Comprehensive clinical and safety monograph for ASMANEX TWISTHALER (ASMANEX TWISTHALER).
| Placental transfer | Minimal to none due to low systemic absorption after inhalation; no data on active transfer. |
| Breastfeeding | Low systemic bioavailability; unlikely to pass into breast milk in significant amounts. Use caution, although generally considered compatible with breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
Long-term use of inhaled corticosteroids may increase the risk of adrenal insufficiency during stress or withdrawal. Not indicated for relief of acute bronchospasm.
| Common Effects | Headache, Throat irritation, Hoarseness (dysphonia), Cough, Epistaxis, Sinusitis, Upper respiratory tract infection |
| Serious Effects | Adrenal insufficiency (with prolonged use or high doses), Increased risk of pneumonia in patients with COPD, Oropharyngeal candidiasis, Paradoxical bronchospasm, Growth suppression in children, Osteoporosis with long-term use, Cataracts and glaucoma |
Status asthmaticusHypersensitivity to mometasone furoate or any component
| Precautions | Risk of adrenal insufficiency with systemic absorption, especially at high doses or prolonged use, Potential for growth suppression in children and adolescents, Increased risk of infections (e.g., oral candidiasis, pneumonia in COPD patients), Paradoxical bronchospasm with immediate wheezing after dosing, Systemic corticosteroid withdrawal effects when transitioning from oral to inhaled therapy, Osteoporosis with long-term use, Glaucoma and cataracts |
Loading safety data…
| L2 (Safer) |
| Teratogenic Risk | Insufficient human data; animal studies show no teratogenicity at clinically relevant doses. Inhaled corticosteroids are generally considered low risk. No specific trimester risks identified. |
| Fetal Monitoring | Monitor maternal asthma control, lung function, and fetal growth via ultrasound if prolonged use. No specific drug level monitoring required. |
| Fertility Effects | No evidence of impaired fertility at clinical doses; animal studies show no effect on fertility. |
| Food/Dietary | No significant food interactions. Grapefruit juice does not affect mometasone pharmacokinetics. No dietary restrictions necessary. However, avoid excessive alcohol consumption as it may worsen asthma control. |
| Clinical Pearls | Asmanex Twisthaler (mometasone furoate) is an inhaled corticosteroid (ICS) indicated for maintenance treatment of asthma. It is not for acute bronchospasm or status asthmaticus. Onset of therapeutic effect may take 1-2 weeks; adherence is critical. Use the lowest effective dose. Rinse mouth with water after each use to reduce risk of oral candidiasis. Monitor for signs of adrenal suppression when switching from systemic corticosteroids. In children, monitor growth velocity. No systemic drug interactions of significance due to low oral bioavailability and extensive first-pass metabolism. |
| Patient Advice | This medication is a controller, not a rescue inhaler; use it daily as prescribed, even if symptom-free. · Rinse your mouth with water (do not swallow) after each use to prevent thrush (oral yeast infection). · Twist the base to fully open and load the dose; inhale deeply and rapidly through the mouthpiece; do not exhale into the device. · Keep the device clean and dry; do not wash the mouthpiece; store at room temperature away from moisture. · Contact your healthcare provider if symptoms worsen or you need more frequent rescue inhaler use. · Do not stop this medication abruptly; dosage reduction should be supervised by a doctor. · Inform your doctor if you experience vision changes (risk of glaucoma/cataracts) or signs of infection. |