Pharmacology · Inhaled corticosteroids
Budesonide + formoterol !
One inhaler with a corticosteroid and a fast, long-acting beta-2 agonist. Controls asthma and COPD; in some schemes it also serves as the reliever.
Updated 2026-11-01
The figure shows the budesonide side of the combination: the human glucocorticoid receptor with fluticasone furoate, an inhaled corticosteroid in the same pocket. Formoterol on the beta-2 receptor appears on the formoterol page.
Mechanism of action
The two drugs work on different targets in the same airway. Budesonide binds the glucocorticoid receptor and turns down airway inflammation over days to weeks. Formoterol activates the beta-2 receptor, raises cyclic AMP and relaxes the bronchial muscle within minutes for many hours. Giving both in one inhaler guarantees that the LABA is never used without the steroid.
- Budesonide binds the glucocorticoid receptor and calms airway inflammation
- Formoterol activates the beta-2 receptor and relaxes airway muscle
- Formoterol acts within minutes and lasts many hours
- One inhaler keeps the LABA always paired with the steroid
Pharmacokinetics
- Absorption
- Both act mainly in the lung; budesonide undergoes extensive first-pass metabolism
- Metabolism
- Budesonide by CYP3A4; formoterol by glucuronidation and O-demethylation
- Elimination
- Metabolites in urine and faeces
- Onset and duration
- Formoterol relieves bronchospasm within minutes; the steroid effect builds over days
Indications
- Treatment of asthma, as maintenance and, in some guidelines, also as reliever Asthma →
- Maintenance treatment of COPD and reduction of exacerbations Chronic obstructive pulmonary disease (COPD) →
Adverse effects
Common
- Oral thrush and hoarseness
- Nasopharyngitis and upper respiratory infection
- Headache
- Tremor and palpitations
Contraindications
- Primary treatment of status asthmaticus or acute episodes needing intensive measures
- Hypersensitivity to budesonide, formoterol or any component
- Not combined with another inhaler containing a LABA (risk of overdose)
Key interactions
- Strong CYP3A4 inhibitors (ritonavir, ketoconazole)
- Higher budesonide levels and systemic steroid effects
- Beta blockers
- Block formoterol and may cause severe bronchospasm in asthma
- Non-potassium-sparing diuretics
- Additive hypokalaemia and ECG changes
- Monoamine oxidase inhibitors or tricyclic antidepressants
- Stronger effects of formoterol on the cardiovascular system
What is monitored
- Asthma or COPD control and exacerbations
- Mouth for thrush
- Signs of pneumonia in COPD
- Potassium and glucose in high-risk patients
Administration and safety
- Oral inhalation; the pressurised inhaler is shaken and primed, and can be used with a spacer
- After each use the mouth is rinsed with water and the water spat out
- It is not combined with other LABA-containing inhalers
- Whether it is used only as maintenance or also as reliever depends on the treatment plan; the patient's written plan says which
Nursing care
- Check inhaler technique and the written asthma plan (maintenance only, or maintenance and reliever)
- Look at the mouth for thrush and ask about hoarseness
- Check heart rate and watch for tremor; in COPD, watch for fever, cough or sputum change (pneumonia)
- Teach that a sudden worsening needs urgent review, not just more puffs
Pregnancy and breastfeeding
Each component has been used in pregnancy; good asthma control matters, because poorly controlled asthma raises the risk of preeclampsia and prematurity.
Test yourself
Think of the answer, then tap the question to see it.
Why can budesonide + formoterol be used as a reliever in some asthma plans, but fluticasone + salmeterol cannot?
Formoterol acts within minutes, while salmeterol has a slow onset; so only the formoterol combination can relieve symptoms quickly.
What is the safety reason for combining a LABA and an inhaled corticosteroid in one inhaler?
LABA alone in asthma raises serious asthma-related events; the single inhaler makes sure the steroid is always taken with it.
Which infection is more frequent with this combination in COPD?
Pneumonia, from the inhaled corticosteroid.
Related drugs
Related conditions
← Back to the class: Inhaled corticosteroids
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 - BUDESONIDE AND FORMOTEROL FUMARATE DIHYDRATE aerosol, metered (DailyMed (U.S. National Library of Medicine), 2026); Budesonide inhalers: medicine to treat asthma - NHS (NHS, 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.