budesonide/formoterol
Symbicort combines budesonide and formoterol in a single inhaler from AstraZeneca for the regular treatment of asthma and chronic obstructive pulmonary disease (COPD). Budesonide calms inflammation in the airways, while formoterol keeps the muscles around the airways relaxed for up to 12 hours.
This page is based on EMA assessment information for budesonide/formoterol (DuoResp Spiromax) and FDA prescribing information for budesonide inhalation suspension; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
The airways are like pipes that can get swollen on the inside and tight on the outside. Budesonide reduces the swelling from within by calming the immune response, and formoterol relaxes the muscle band around the outside so the pipe stays open. Together they make breathing easier and keep it that way.
In simple terms
Budesonide and formoterol are two medicines in one inhaler that work together on the airways. Budesonide is an inhaled corticosteroid that reduces swelling, redness and irritation inside the lungs, treating the underlying inflammation of asthma and COPD. Formoterol is a long-acting beta-2 agonist that relaxes the band of muscle around the airways, keeping them open for up to 12 hours. Used regularly every day, the combination helps prevent symptoms such as wheezing, breathlessness and chest tightness. It is not meant to relieve a sudden attack of breathlessness — a separate fast-acting inhaler is used for that.
In depth
Budesonide is an inhaled corticosteroid that binds to cytoplasmic glucocorticoid receptors, translocates to the nucleus and modulates gene transcription — up-regulating anti-inflammatory proteins such as lipocortin-1 and down-regulating pro-inflammatory cytokines, chemokines and adhesion molecules — reducing airway oedema, mucus secretion and inflammatory cell infiltration. Formoterol fumarate is a long-acting selective beta-2 adrenergic receptor agonist; binding to beta-2 receptors on airway smooth muscle activates adenylyl cyclase, raising intracellular cyclic AMP and producing sustained bronchodilation with a rapid onset of action (within minutes). The combination provides complementary mechanisms: budesonide treats the underlying inflammation while formoterol maintains airway calibre, and budesonide also up-regulates beta-2 receptor expression, reducing the risk of tachyphylaxis to formoterol.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How formoterol keeps the airways open as a long-acting beta-2 agonist
- Formoterol is a long-acting beta-2 agonist that relaxes the band of muscle around the airways, keeping them open for up to 12 hours.
- Formoterol fumarate is a long-acting selective beta-2 adrenergic receptor agonist; binding to beta-2 receptors on airway smooth muscle activates adenylyl cyclase, raising intracellular cyclic AMP and producing sustained bronchodilation
- budesonide also up-regulates beta-2 receptor expression, reducing the risk of tachyphylaxis to formoterol.
- It is not meant to relieve a sudden attack of breathlessness — a separate fast-acting inhaler is used for that.
Target: Glucocorticoid receptor and beta-2 adrenergic receptor
The glucocorticoid receptor mediates the anti-inflammatory effects of budesonide in airway cells; the beta-2 adrenergic receptor mediates bronchodilation when formoterol binds to smooth muscle surrounding the airways.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMA- Asthma: regular treatment of asthma in adults and adolescents (12 years and older), where use of a combination (inhaled corticosteroid and long-acting beta-2 adrenoceptor agonist) is appropriate — in patients not adequately controlled with inhaled corticosteroids and "as needed" inhaled short-acting beta-2 adrenoceptor agonists, or in patients already adequately controlled on both inhaled corticosteroids and long-acting beta-2 adrenoceptor agonists
- COPD: symptomatic treatment of adults with COPD with FEV1 less than 70% predicted normal (post bronchodilator) and a history of repeated exacerbations, who have significant symptoms despite regular therapy with long-acting bronchodilators
Approved uses in United States
FDA- Budesonide inhalation suspension is indicated for the maintenance treatment of asthma and as prophylactic therapy in children 12 months to 8 years of age
Official sources
The statements on this page trace back to these records.
- U.S. Food and Drug Administration: budesonide inhalation suspension prescribing information
U.S. Food and Drug Administration
- Emc SmPC: Budesonide (UK licensed product)
Medicines and Healthcare products Regulatory Agency (EMC)
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.