AIRDUO DIGIHALER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AIRDUO DIGIHALER (AIRDUO DIGIHALER).
Salmeterol is a long-acting beta2-adrenergic agonist (LABA) that relaxes bronchial smooth muscle by increasing cyclic AMP. Fluticasone propionate is a corticosteroid with anti-inflammatory activity that inhibits inflammatory mediators and cells.
| Metabolism | Fluticasone propionate is metabolized primarily by CYP3A4. Salmeterol is metabolized by CYP3A4 to alpha-hydroxysalmeterol. |
| Excretion | Fluticasone furoate and vilanterol are primarily eliminated via biliary/fecal routes. For fluticasone furoate, approximately 90% of an oral dose is excreted in feces as parent drug and metabolites, with <1% in urine. Vilanterol is predominantly excreted via feces (∼70%) as metabolites, with ∼20% in urine. |
| Half-life | Fluticasone furoate: terminal elimination half-life is approximately 24 hours. Vilanterol: terminal elimination half-life is approximately 11 hours. The long half-life of fluticasone furoate supports once-daily dosing, while vilanterol's half-life allows for sustained bronchodilation over 24 hours. |
| Protein binding | Fluticasone furoate: >99% bound to plasma proteins (primarily albumin). Vilanterol: approximately 94% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Fluticasone furoate: mean Vd is approximately 4.2 L/kg (range 1.2-9.5 L/kg), indicating extensive tissue distribution. Vilanterol: mean Vd is approximately 7.5 L/kg, indicating extensive distribution into tissues. |
| Bioavailability | Inhalation: The absolute bioavailability of fluticasone furoate is approximately 15.2% (due to lung deposition and swallowed portion undergoing first-pass metabolism). Vilanterol absolute bioavailability is approximately 27.3% (primarily from lung absorption, with low oral bioavailability due to extensive first-pass metabolism). Oral bioavailability of both is <2%. |
| Onset of Action | Inhalation: Onset of bronchodilation (vilanterol component) occurs within 15 minutes, with clinically meaningful improvement in FEV1 observed at 15-30 minutes post-dose. |
| Duration of Action | Inhalation: Duration of bronchodilation (vilanterol component) is at least 24 hours, allowing once-daily dosing. The anti-inflammatory effect of fluticasone furoate persists for the dosing interval. |
Two inhalations (umeclidinium 62.5 mcg and vilanterol 25 mcg per inhalation) orally once daily.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl <30 mL/min) or end-stage renal disease, use with caution. |
| Liver impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh A). Not studied in moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment, use with caution. |
| Pediatric use | Not indicated for pediatric patients under 18 years of age. |
| Geriatric use | No dose adjustment required based on age alone; monitor for anticholinergic effects and reduced renal function in patients 65 years and older. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AIRDUO DIGIHALER (AIRDUO DIGIHALER).
| Breastfeeding | Budesonide and formoterol are excreted in human breast milk in low concentrations. M/P ratios: budesonide approximately 0.4; formoterol data limited. No adverse effects reported in infants at therapeutic maternal doses. Caution is advised, particularly with high doses or prolonged use. Monitor infant for signs of adrenal suppression or beta-adrenergic effects. |
| Teratogenic Risk | No adequate and well-controlled studies in pregnant women. In animal studies, corticosteroids have been shown to be teratogenic. Budesonide (an ICS) is associated with increased risk of orofacial clefts and other malformations at high doses; however, inhaled doses at therapeutic levels have not shown consistent human teratogenicity. Formoterol (a LABA) has been associated with fetal harm in animal studies. Risk is not clearly defined; use only if potential benefit justifies risk. First trimester: potential association with orofacial clefts from ICS; second/third trimester: risk of fetal growth restriction and adrenal suppression from chronic high-dose corticosteroids. |
■ FDA Black Box Warning
LABA increase the risk of asthma-related death. AIRDUO DIGIHALER should only be used in patients with asthma not adequately controlled on a long-term asthma control medication, or whose disease severity warrants initiation of both an inhaled corticosteroid and a LABA. Once asthma control is achieved, assess and possibly step down therapy.
| Serious Effects |
["Status asthmaticus or acute episodes of asthma or COPD requiring intensive therapy","Primary treatment of acute bronchospasm","Severe hypersensitivity to salmeterol, fluticasone propionate, or any ingredient"]
| Precautions | ["Serious asthma-related events including death","Increased risk of pneumonia in COPD patients","Cardiovascular effects (e.g., increased blood pressure, tachycardia) with beta-agonists","Hypersensitivity reactions","Systemic corticosteroid effects (e.g., adrenal insufficiency, growth suppression) with high doses or prolonged use","Paradoxical bronchospasm","Reduced bone mineral density with long-term use"] |
| Food/Dietary | No clinically significant food interactions. Avoid grapefruit juice if taking strong CYP3A4 inhibitors, though not required for AIRDUO alone. |
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| Fetal Monitoring | Monitor maternal asthma control and pulmonary function tests (PFTs) regularly. Assess fetal growth and well-being via ultrasonography, especially if high-dose ICS used. Monitor for maternal hyperglycemia and blood pressure. In neonates, monitor for signs of adrenal insufficiency, especially if maternal high-dose corticosteroids used near term. |
| Fertility Effects | No specific human data on fertility. In animal studies, high doses of corticosteroids may impair fertility; formoterol did not affect fertility at clinically relevant doses. Inhaled beta-agonists are not expected to significantly impact fertility. |
| Clinical Pearls | AIRDUO DIGIHALER (fluticasone propionate/salmeterol) is a combination ICS/LABA for maintenance treatment of asthma or COPD. Not for acute bronchospasm. Rinse mouth after use to prevent oral candidiasis. Monitor for adrenal insufficiency during stress or dose reduction. Do not use with strong CYP3A4 inhibitors (e.g., ritonavir) due to increased fluticasone systemic effects. |
| Patient Advice | Use exactly as prescribed; not for sudden breathing problems. · Prime the inhaler before first use and if not used for ≥7 days. · Rinse mouth with water (do not swallow) after each use to reduce thrush risk. · Know the difference between maintenance and rescue inhaler. · Seek medical attention if bronchodilator use increases or symptoms worsen. · Store at room temperature; do not puncture or burn the canister. |