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. |
| Molecular Weight | 430.53 |
| Action Class | Inhaled Corticosteroid |
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 | Insufficient human data; based on animal studies, budesonide is not associated with major malformations. Use only if benefit justifies risk. |
| 2nd trimester | Inhaled budesonide is considered safe; no increased risk of adverse fetal outcomes observed. Monitor for maternal asthma control. |
| 3rd trimester | Safe for use; maintain asthma control to prevent maternal hypoxia. No known risk of fetal harm. |
Clinical note
Comprehensive clinical and safety monograph for PULMICORT FLEXHALER (PULMICORT FLEXHALER).
| Placental transfer | Budesonide crosses the placenta, but systemic bioavailability after inhalation is low (10-50%). Fetal exposure is minimal at inhaled doses. |
| Breastfeeding | Inhaled budesonide at recommended doses results in negligible systemic exposure; concentrations in breast milk are too low to cause adverse effects in infants. Considered compatible with breastfeeding. |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | Headache, Throat irritation, Cough, Hoarseness (dysphonia), Sinusitis, Upper respiratory tract infection |
| Serious Effects | Adrenal insufficiency (with prolonged use or high doses), Increased risk of pneumonia in patients with COPD, Oropharyngeal candidiasis, Paradoxical bronchospasm, Reduced bone mineral density with long-term use, Growth suppression in children, Glaucoma and cataracts |
Hypersensitivity to budesonide or any ingredientUntreated fungal, bacterial, or viral infections of the respiratory tract
| 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 |
Loading safety data…
| Lactation Rating | L1 (Safe) |
| 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. |
| 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. |
| Food/Dietary |
| No specific food interactions; avoid grapefruit juice only if taking certain drugs that interact with budesonide (e.g., ketoconazole) - but generally not a concern with inhaled budesonide. No dietary restrictions required. |
| Clinical Pearls | Pulmicort Flexhaler (budesonide) is an inhaled corticosteroid for asthma maintenance. Not for acute bronchospasm. Rinse mouth after use to prevent oral candidiasis. Titrate to lowest effective dose. May need to wean oral corticosteroids slowly. Monitor for adrenal insufficiency during stress or surgery. Discard after labeled number of actuations; dose counter shows remaining doses. |
| Patient Advice | Use exactly as prescribed; do not use for sudden breathing problems. · Prime the inhaler before first use or if not used for 2+ weeks: twist the brown grip to the right then left until it clicks. · Breathe out fully, place mouthpiece in mouth, close lips, and inhale deeply and forcefully through the mouth. · Hold breath for 10 seconds (or as long as comfortable), then exhale slowly. · Rinse mouth with water (do not swallow) after each dose to prevent thrush. · Clean mouthpiece weekly with dry cloth; do not wash or put in water. · Keep track of doses using the dose indicator window; discard when it reaches 0 (even if it feels like some left). · Do not stop taking this medication suddenly; consult your doctor before stopping. · Carry a rescue inhaler (e.g., albuterol) for acute symptoms. |