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. |
| Molecular Weight | Fenoterol HBr: 348.3 Da; Ipratropium Br: 412.4 Da |
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 | No adequate data; risk cannot be excluded. Avoid unless essential. |
| 2nd trimester | No adequate data; risk cannot be excluded. Avoid unless essential. |
| 3rd trimester | May inhibit uterine contractions and cause fetal bradycardia. Avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for DUO-MEDIHALER (DUO-MEDIHALER).
| Placental transfer | Fenoterol and ipratropium cross placenta; minimal systemic absorption limits fetal exposure. |
| Breastfeeding | Inhaled dose is low; unlikely to affect infant. Use caution with high doses or prolonged therapy. |
| Lactation Rating |
■ 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 fenoterol, ipratropium, or atropine derivativesTachyarrhythmiaHypertrophic obstructive cardiomyopathy
| 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 |
| Food/Dietary | Avoid excessive caffeine (coffee, tea, cola) as it may increase cardiac side effects. No specific food restrictions, but hypokalemia risk increases with potassium-lowering diets. |
Loading safety data…
| L2: Limited data - probably compatible |
| 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. |
| 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. |
| Clinical Pearls | DUO-MEDIHALER (ipratropium bromide and fenoterol hydrobromide) is a fixed-dose combination for COPD and asthma. Fenoterol is a β2-agonist with a faster onset than salbutamol but higher cardiac stimulation risk. Ipratropium is an anticholinergic that dries secretions; combine with fenoterol for additive bronchodilation. Use with caution in patients with tachyarrhythmias, hypertrophic obstructive cardiomyopathy, or thyrotoxicosis. Monitor serum potassium; fenoterol can cause hypokalemia. Do not exceed 12 inhalations daily. |
| Patient Advice | Shake the inhaler well before each use. · Exhale fully, then place mouthpiece in mouth and seal lips around it. · Press the canister while inhaling deeply and slowly; hold breath for 10 seconds. · Rinse mouth with water after use to prevent oral thrush and dryness. · Do not use more than 12 inhalations in 24 hours; overuse can cause heart problems. · If you have chest pain, fast irregular heartbeat, or worsening breathing, seek medical help. · Avoid getting the spray in eyes; it may cause eye pain or blurred vision. · Store at room temperature away from heat and open flames. |