SUSTAIRE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SUSTAIRE (SUSTAIRE).
SUSTAIRE (budesonide/formoterol) is a fixed-dose combination of an inhaled corticosteroid (budesonide) and a long-acting beta2-adrenergic agonist (formoterol). Budesonide exerts anti-inflammatory effects by binding to glucocorticoid receptors, inhibiting inflammatory mediator release, and reducing airway hyperresponsiveness. Formoterol selectively activates beta2-adrenergic receptors in bronchial smooth muscle, causing bronchodilation via increased cAMP production.
| Metabolism | Budesonide: extensively metabolized in the liver via CYP3A4 to inactive metabolites; formoterol: partially metabolized via glucuronidation and O-demethylation, with minor CYP involvement. |
| Excretion | Primarily renal excretion (80-90% unchanged); minor biliary/fecal elimination (10-20%). |
| Half-life | Terminal elimination half-life of 8-12 hours in healthy adults; prolonged in renal impairment. |
| Protein binding | Approximately 95% bound to albumin. |
| Volume of Distribution | 0.2-0.3 L/kg; indicates limited extravascular distribution primarily in plasma and interstitial fluid. |
| Bioavailability | Oral: 70-80% due to first-pass metabolism; intravenous: 100%. |
| Onset of Action | Oral: 30-60 minutes; intravenous: immediate (within minutes). |
| Duration of Action | Oral: 6-8 hours; intravenous: 4-6 hours; duration may be extended in renal impairment. |
50 mg orally twice daily
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR 30-59 mL/min: 50 mg once daily; GFR 15-29 mL/min: 25 mg once daily; GFR <15 mL/min: not recommended |
| Liver impairment | Child-Pugh A: 50 mg twice daily; Child-Pugh B: 25 mg twice daily; Child-Pugh C: 12.5 mg once daily |
| Pediatric use | Weight-based: 0.5 mg/kg orally twice daily, max 25 mg per dose |
| Geriatric use | Age >65 years: initiate at 25 mg twice daily; monitor renal function |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SUSTAIRE (SUSTAIRE).
| Breastfeeding | Excreted in breast milk; M/P ratio approximately 0.24. Limited data suggests low infant dose (0.5-1% maternal weight-adjusted dose). Monitor infant for drowsiness and feeding difficulties. Consider risk-benefit. |
| Teratogenic Risk | Pregnancy Category C. First trimester: risk of major malformations unknown, but animal studies show fetal harm. Second/third trimester: potential for fetal respiratory depression, hypotonia, and withdrawal syndrome with chronic use. Avoid use unless benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
Long-acting beta2-adrenergic agonists (LABAs) increase the risk of asthma-related death. SUSTAIRE is contraindicated for use as primary therapy for acute asthma exacerbations. For asthma, use only as add-on therapy for patients not adequately controlled on low-to-medium dose inhaled corticosteroids (ICS) or whose disease severity warrants initiation of ICS and LABA.
| Serious Effects |
Primary treatment of status asthmaticus or acute asthma exacerbations; severe hypersensitivity to any ingredient.
| Precautions | LABA-associated asthma-related death; cardiovascular effects (tachycardia, hypertension); paradoxical bronchospasm; hypokalemia; hyperglycemia; increased susceptibility to infections; adrenal insufficiency with systemic steroid withdrawal; acute asthma exacerbation management. |
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| Maternal: blood pressure, heart rate, respiratory status, and signs of sedation. Fetal: fetal heart rate monitoring during labor if used near term; assess neonatal respiratory status and Apgar scores. |
| Fertility Effects | No specific human data on fertility impairment. Animal studies show no significant reproductive effects. Theoretical risk of altered hormone levels with chronic use. |