What it is
Budesonide is a potent inhaled corticosteroid that acts in the airways. The part that is swallowed undergoes almost complete first-pass metabolism in the liver, so at low and moderate doses there are few effects on the rest of the body. In asthma it controls inflammation, and in COPD it reduces exacerbations in selected patients.
Current asthma guidelines (GINA) recommend that every adult or adolescent with asthma uses an inhaled corticosteroid, not just a reliever bronchodilator. The budesonide-formoterol combination can also be used as a reliever in specific regimens the doctor decides.
Mechanism of action
It acts locally:
- Agonist of glucocorticoid receptors in inflammatory cells (eosinophils, mast cells)
- It reduces the synthesis of inflammatory mediators (cytokines, leukotrienes)
- It reduces oedema and mucus hypersecretion in the airways
At the counter
When to recommend it
- Persistent asthma (control of inflammation)
- More severe asthma, combined with a long-acting bronchodilator
- COPD with frequent exacerbations, combined according to the guidelines
- Prevention of asthma exacerbations
When not to
- Allergy to budesonide
- Active pulmonary tuberculosis or untreated fungal respiratory infection (caution)
- As a reliever in an attack: on its own it does not work, it is too slow
- Stopping it suddenly once asthma is controlled, without discussing it with the doctor
Warnings
- Important Pneumonia: in COPD, inhaled corticosteroids slightly increase the risk of pneumonia. Warn about fever, productive cough or getting worse.
- Caution Oral thrush: common if the mouth is not rinsed. It is prevented by rinsing and spitting after each use.
- Caution Dysphonia (hoarseness): common, from local irritation.
- Caution At high, prolonged doses, systemic effects can appear: growth in children, cataracts, bone loss. Use the lowest effective dose.
Pharmacokinetics
- Absorption
- The fraction that reaches the lung is absorbed there; the swallowed fraction is absorbed in the gut.
- Distribution
- Its aim is local action in the lung; systemic distribution at usual doses is low.
- Metabolism
- The swallowed fraction undergoes almost complete first-pass hepatic metabolism (CYP3A4) into metabolites with no relevant activity. That is why strong CYP3A4 inhibitors (ritonavir, itraconazole) can increase its systemic effects.
- Elimination
- Renal elimination of metabolites. Systemic half-life of 2–3 hours.
Inhaled budesonide vs salbutamol
| Aspect | Inhaled budesonide | Salbutamol (SABA) |
|---|---|---|
| Mechanism | Anti-inflammatory (prevention) | Bronchodilator (quick relief) |
| Type of use | Daily, preventive | As needed, acute |
| Time to effect | Gradual (maximum in 2–4 weeks) | Fast (5–10 min) |
| Systemic effects | Minimal | Tachycardia, tremor |
| In an acute attack | No (too slow) | Yes, it is the choice |
Budesonide prevents; salbutamol relieves. They complement each other. The budesonide-formoterol combination can do both jobs in regimens the doctor decides.
Self-assessment
Three questions. When you check your answers you will see the explanation for each one.
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Inhaled budesonide acts where it is needed (the lung) and the swallowed part is inactivated in the liver, so at usual doses it has few effects on the rest of the body.
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Budesonide is a maintenance treatment. In an acute attack a fast bronchodilator (salbutamol) is needed.
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Oral thrush is common if the mouth is not rinsed. It is easily prevented by rinsing and spitting after inhaling.
Training content. It does not replace the summary of product characteristics or clinical judgement.