Budesonide
Budesonide is a potent synthetic glucocorticoid engineered for high first-pass hepatic metabolism, so it delivers strong local anti-inflammatory action in the airways or gut with comparatively low systemic exposure. It is a mainstay inhaled steroid for asthma and an oral formulation targeting ileal/colonic inflammation in Crohn's disease. Lower systemic burden than oral prednisone, but not zero — HPA suppression still occurs at higher doses.
01 Overview
Budesonide's design exploits extensive first-pass metabolism: roughly 90% of an absorbed oral dose is inactivated by the liver before reaching the systemic circulation, concentrating the glucocorticoid effect at the target tissue. Inhaled budesonide controls asthma with far less systemic effect than oral steroids, and enteric-release oral budesonide treats mild-to-moderate Crohn's disease and microscopic colitis with fewer classic corticosteroid side effects.
It is not free of systemic effect: higher inhaled or oral doses still suppress the HPA axis and can affect bone and glucose over time, and inhaled use causes local oral candidiasis. Inhaled glucocorticoids are permitted under WADA rules, but oral/systemic budesonide is prohibited in-competition.
02 Mechanism
High-affinity glucocorticoid receptor agonist with extensive hepatic first-pass metabolism, maximising local (airway/gut) anti-inflammatory action while limiting systemic exposure.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Crohn's / colitis | 3–9 mg/day | Oral | Enteric-release; 9 mg/day induction for ileal Crohn's disease. |
| Asthma | 200–800 mcg/day | Inhaled | Inhaled maintenance; higher doses raise systemic exposure. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Targeted anti-inflammatory actionStrong airway or gut inflammation control with reduced systemic side effects. | high local, low systemic | Clinical | |
| Fewer systemic steroid effectsHigh first-pass metabolism limits classic corticosteroid toxicity at standard doses. | vs oral prednisone | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Oral candidiasis / dysphonia (inhaled)Oral thrush and hoarseness from local steroid deposition in the mouth/throat. | Mild | Common with inhaled use | Clinical | |
| HPA suppression (higher doses)Measurable adrenal suppression at high inhaled or prolonged oral doses. | Moderate | At higher/prolonged doses | Clinical | |
| Reduced bone density (prolonged)Small effect on bone with sustained high exposure. | Mild | With prolonged high-dose use | Clinical |