Pharmacology · Class
Inhaled corticosteroids !
Steroids breathed into the lungs to calm airway inflammation. The most effective controller medicines for asthma; they do not relieve an attack.
Updated 2026-11-01
What they are
Glucocorticoids delivered by inhaler or nebuliser (budesonide, beclometasone, fluticasone, ciclesonide, mometasone). They are the basis of long-term asthma control and, in COPD, are added for patients with frequent exacerbations. They are often combined with a long-acting beta-2 agonist in one inhaler.
Mechanism of action
The steroid crosses the cell membrane and binds the cytoplasmic glucocorticoid receptor, which moves to the nucleus. There it switches off inflammatory genes (cytokines, chemokines, adhesion molecules) by blocking transcription factors such as NF-kB and AP-1, and switches on anti-inflammatory genes. Eosinophils, mast cells and T cells in the airway fall and airway hyperresponsiveness decreases. Delivery to the lung and extensive first-pass liver metabolism of the swallowed part keep systemic effects low.
Target: Glucocorticoid receptor (NR3C1), a nuclear receptor
Drugs in this class
- BudesonideAn inhaled corticosteroid that controls asthma by calming airway inflammation. Used daily as a preventer, by inhaler…Glucocorticoid receptor
- Budesonide + formoterolOne inhaler with a corticosteroid and a fast, long-acting beta-2 agonist. Controls asthma and COPD; in some schemes it…Glucocorticoid receptor (budesonide) and beta-2 adrenergic receptor (formoterol)
- BeclometasoneOne of the oldest inhaled corticosteroids, a daily asthma preventer. It is a prodrug activated in the lung.Glucocorticoid receptor
- FluticasoneA potent inhaled corticosteroid for asthma and, in combinations, COPD. Almost none of the swallowed drug reaches the…Glucocorticoid receptor
Others in the class
- Ciclesonide
- Mometasone
Test yourself
Think of the answer, then tap the question to see it.
How do inhaled corticosteroids reduce airway inflammation at the gene level?
The activated glucocorticoid receptor blocks transcription factors such as NF-kB and AP-1, switching off inflammatory genes, and switches on anti-inflammatory ones.
What two measures reduce oral thrush from an inhaled corticosteroid?
Rinsing the mouth with water and spitting it out after each use, and using a spacer with a pressurised inhaler.
Which antiretroviral booster causes Cushing syndrome with inhaled fluticasone?
Ritonavir, a strong CYP3A4 inhibitor that greatly raises systemic fluticasone levels.
Which respiratory infection is more frequent with inhaled corticosteroids in COPD?
Pneumonia.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - FLUTICASONE PROPIONATE HFA- fluticasone propionate aerosol, metered (DailyMed (U.S. National Library of Medicine), 2023); DailyMed - BUDESONIDE AND FORMOTEROL FUMARATE DIHYDRATE aerosol, metered (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 44 (McGraw Hill, 2023).
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Representative model, for educational purposes only.