DUO-MEDIHALER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DUO-MEDIHALER (DUO-MEDIHALER).
Combination of fluticasone propionate, a corticosteroid with anti-inflammatory activity, and salmeterol, a long-acting beta2-adrenergic agonist (LABA) that relaxes bronchial smooth muscle by stimulating intracellular adenyl cyclase, increasing cyclic AMP levels.
| Metabolism | Fluticasone propionate is metabolized primarily by CYP3A4 to an inactive metabolite. Salmeterol is metabolized by hydroxylation via CYP3A4. |
| Excretion | Renal: 70-80% (free drug and metabolites), Biliary/Fecal: 10-20% |
| Half-life | Terminal elimination half-life of 3-4 hours for the bronchodilator component and 6-8 hours for the corticosteroid component; clinically requires twice-daily dosing. |
| Protein binding | Bronchodilator: 40-50% to albumin; Corticosteroid: 85-90% to albumin and corticosteroid-binding globulin. |
| Volume of Distribution | Bronchodilator: 4.5 L/kg; Corticosteroid: 3.5 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Inhalation: 15-30% for bronchodilator, 20-30% for corticosteroid; oral bioavailability <5% due to first-pass metabolism. |
| Onset of Action | Inhalation: within 5-10 minutes for bronchodilator effect; corticosteroid effect requires hours to days. |
| Duration of Action | Bronchodilator: up to 12 hours; corticosteroid: sustained effect with regular use. |
Two inhalations (50 mcg ipratropium bromide and 100 mcg fenoterol hydrobromide per inhalation) four times daily via metered-dose inhaler.
| Dosage form | AEROSOL, METERED |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (GFR <30 mL/min), use with caution and consider reduced frequency to three times daily. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). For severe hepatic impairment (Child-Pugh C), reduce dose to one inhalation three times daily. |
| Pediatric use | Children (6–12 years): One inhalation twice daily, up to maximum two inhalations twice daily. Weight-based dosing not established; use age-based guidelines. |
| Geriatric use | No specific dose adjustment, but monitor for anticholinergic side effects (e.g., dry mouth, urinary retention). Use with caution in patients with glaucoma or prostatic hyperplasia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DUO-MEDIHALER (DUO-MEDIHALER).
| Breastfeeding | Fenoterol may be excreted in breast milk; ipratropium is poorly absorbed orally and likely not detectable. M/P ratio not available. Use with caution in breastfeeding mothers, weighing benefit vs. risk. |
| Teratogenic Risk | DUO-MEDIHALER (ipratropium bromide and fenoterol hydrobromide): No adequate human studies. In animal studies, fenoterol showed no teratogenicity at doses up to 100 mg/kg/day SC (rats) and 10 mg/kg/day SC (rabbits). Ipratropium showed no teratogenicity at doses up to 125 mg/kg/day SC (rats) and 15 mg/kg/day SC (rabbits). Risk cannot be excluded; use only if clearly needed. First trimester: theoretical risk based on beta-agonist systemic effects. Second and third trimesters: beta-agonists may cause tachycardia, hyperglycemia; ipratropium minimal absorption. |
■ FDA Black Box Warning
LABAs increase the risk of asthma-related death. DUO-MEDIHALER should only be used for asthma in patients not adequately controlled on a long-term asthma control medication or whose disease severity warrants initiation of both an inhaled corticosteroid and a LABA.
| Serious Effects |
["Hypersensitivity to any ingredient","Primary treatment of status asthmaticus or acute episodes of asthma or COPD requiring intensive measures","Use with another LABA (e.g., salmeterol, formoterol) for asthma"]
| Precautions | ["Increased risk of asthma-related death","Serious cardiovascular events and nervous system effects with beta-agonists","Candidiasis of mouth and throat","Pneumonia in COPD patients","Adrenal insufficiency","Hypercorticism and adrenal suppression with high doses","Hypersensitivity reactions including anaphylaxis","Paradoxical bronchospasm","Ketoacidosis in diabetic patients"] |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and blood glucose; fetal heart rate monitoring if used for tocolysis or in labor. Assess for maternal bronchospasm or adverse effects. |
| Fertility Effects | No specific studies. Animal studies: fenoterol and ipratropium showed no adverse effects on fertility at clinically relevant doses. Theoretical risk of beta-agonist effects on ovarian function unclear. |