PULMICORT FLEXHALER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PULMICORT FLEXHALER (PULMICORT FLEXHALER).
Budesonide is a corticosteroid with potent anti-inflammatory effects. It inhibits multiple inflammatory cell types and mediators such as cytokines, chemokines, and adhesion molecules, reducing airway hyperresponsiveness and inflammation.
| Metabolism | Primarily metabolized by CYP3A4 (major) and CYP3A5 (minor) to 6β-hydroxybudesonide and 16α-hydroxyprednisolone, which have negligible glucocorticoid activity. |
| Excretion | Renal: ~60% as metabolites, fecal: ~40% as metabolites. Less than 10% unchanged in urine. |
| Half-life | Terminal half-life: 2.0-3.5 hours (mean 2.5 h) in adults after inhalation. Clinically, duration of effect may persist beyond pharmacokinetic half-life due to receptor binding. |
| Protein binding | 88-90% bound to albumin. |
| Volume of Distribution | Vd = 3.1 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Inhalation: ~20-50% of delivered dose is systemically absorbed (lung deposition ~20-30% of nominal dose); oral bioavailability negligible (<1%). |
| Onset of Action | Inhalation: 24 hours for first measurable effect; peak improvement in 1-2 weeks. |
| Duration of Action | 12-24 hours after single dose; clinically, twice-daily dosing provides sustained asthma control. |
Inhalation: 1-2 inhalations (90-180 mcg) twice daily; maximum 720 mcg twice daily.
| Dosage form | POWDER, METERED |
| Renal impairment | No dose adjustment required. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic impairment due to potential increased systemic exposure. |
| Pediatric use | Children 6-15 years: 1 inhalation (90 mcg) twice daily; maximum 360 mcg twice daily. Children <6 years: not recommended. |
| Geriatric use | No specific dose adjustment; use lowest effective dose due to potential age-related renal/hepatic decline and risk of adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PULMICORT FLEXHALER (PULMICORT FLEXHALER).
| Breastfeeding | Budesonide is excreted into human breast milk in low concentrations. The estimated infant daily dose is approximately 0.3% to 1% of the maternal weight-adjusted dose (M/P ratio not established). At therapeutic doses of inhaled budesonide, no adverse effects on the breastfed infant are anticipated. Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for budesonide and any potential adverse effects on the infant. |
| Teratogenic Risk | Pulmicort Flexhaler (budesonide) is an inhaled corticosteroid. In pregnant women, inhaled budesonide is not associated with an increased risk of major congenital malformations based on data from the Swedish Medical Birth Register (over 2000 exposed pregnancies) and other studies. There is no evidence of teratogenicity or fetotoxicity at therapeutic doses. Use during pregnancy should be considered only if the potential benefit justifies the risk to the fetus. Monitor for maternal adrenal suppression if high doses are used. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Primary treatment of status asthmaticus or acute asthma exacerbation","Hypersensitivity to budesonide or any product component"]
| Precautions | ["Not indicated for relief of acute bronchospasm","Risk of adrenal insufficiency during transfer from systemic corticosteroids","Increased susceptibility to infections (e.g., varicella, measles)","Potential growth suppression in pediatric patients","Monitor for ocular effects (cataracts, glaucoma)","Hypothalamic-pituitary-adrenal (HPA) axis suppression with high doses or prolonged use"] |
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| Fetal Monitoring | Monitor maternal adrenal function if high doses are used. No specific fetal monitoring is required beyond routine prenatal care. Assess for signs of fetal growth restriction if severe maternal asthma is present. |
| Fertility Effects | Based on animal studies, no impairment of fertility was observed with budesonide at subcutaneous doses up to 0.2 mg/kg/day. There are no adequate human studies; however, inhaled corticosteroids at therapeutic doses are not expected to affect fertility. |