Respiratory
Inhaled corticosteroids
Preventer inhalers — The "preventer" inhalers that control airway inflammation in asthma.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
What it is
Inhaled corticosteroids are the cornerstone of asthma control and are also used in some COPD regimens. Delivered straight to the airways, they reduce inflammation with far less systemic effect than steroid tablets.
How it works
They damp down the inflammation in the airway lining that drives asthma, reducing swelling, mucus and twitchiness over time. Because they act on inflammation rather than acute bronchospasm, they prevent attacks rather than relieve them instantly.
In practice
In practice inhaled corticosteroids are the controller that reduces asthma attacks, taken regularly even when well — the opposite of the reliever, which is used as needed. Good inhaler technique and a spacer dramatically improve delivery, and rinsing the mouth afterwards prevents oral thrush and hoarseness. Heavy reliever use with little preventer use is a red flag for poor control.
Examples
Practical use
How to take it & use it well
- Use your preventer inhaler, such as beclometasone or budesonide, regularly every day even when you feel well, as it works by reducing inflammation over time.
- Rinse your mouth with water and spit it out after each dose to lower the chance of a sore mouth or thrush.
- Use a spacer if you have one, as it helps more of the medicine reach your lungs and reduces mouth side effects.
- Remember this is not a reliever, so it will not ease sudden breathlessness; keep your reliever for that.
- If you miss a dose, take it when you remember and carry on as usual; do not take extra to catch up.
- Check your inhaler technique with a pharmacist or nurse, as poor technique is a common reason it does not work well.
Common uses
- Asthma (preventer therapy)
- COPD (in selected combination inhalers)
Monitoring
- Asthma control and inhaler technique at review
- Reliever use as a marker of control
- Growth in children on long-term therapy
Weighing it up
Advantages & disadvantages
Advantages
- Taken regularly, it reduces airway inflammation and helps prevent asthma symptoms and flare-ups.
- Good control means fewer night-time symptoms, less breathlessness and less need for your reliever.
- It delivers medicine straight to the lungs, so doses are small and whole-body side effects are limited.
- It lowers the risk of serious asthma attacks when used consistently.
- It allows many people to stay active and sleep well with stable breathing.
Disadvantages
- It only works if used every day, and the benefit fades if you stop or use it irregularly.
- It does not give instant relief, so it cannot be relied on during an attack.
- It can cause oral thrush or a hoarse voice, which is why rinsing the mouth matters.
- Some people find correct inhaler technique difficult, which reduces how well it works.
- Very high or long-term use can have wider effects, so the aim is the lowest effective amount.
Key safety principles
What to watch for
- Local effects: oral thrush and hoarseness — rinse the mouth after use and use a spacer.
- High doses long-term can have some systemic effects; use the lowest effective dose.
- Not a reliever — does not treat an acute attack.
Key interactions
What to avoid or check alongside
- Certain antifungal and some HIV medicines can raise steroid levels in the body and should be used cautiously together.
- Some macrolide antibiotics can increase the effect of inhaled steroids when taken together.
- Combining it with steroid tablets, creams or nasal sprays adds to the overall steroid load on the body.
- Smoking reduces how well inhaled steroids work, so stopping smoking improves control.
- Mixing up your preventer and reliever inhalers can lead to poor control, so it helps to know which is which.
Patient & carer advice
- Take it every day, even when you feel well
- Rinse your mouth after inhaling
- Use a spacer if advised, and have your technique checked
Answers
Inhaled corticosteroids: frequently asked questions
Is this the same as my blue reliever inhaler?
No. A preventer steroid inhaler is usually brown, orange or another colour and is taken daily. The blue reliever is for sudden symptoms and does not replace the preventer.
Why must I rinse my mouth afterwards?
Some medicine stays in the mouth and throat, which can cause thrush or a hoarse voice. Rinsing and spitting after each dose helps prevent this.
Can I stop once I feel better?
No. The medicine keeps working by controlling inflammation. Stopping can let symptoms return, so only change your treatment on advice.
Are inhaled steroids safe long term?
At preventer doses they are generally considered safe and the local lung delivery keeps body-wide effects low. Regular reviews help keep you on the lowest effective amount.
Does a spacer really help?
Yes. A spacer helps more medicine reach your lungs, improves the effect and reduces mouth side effects, especially if your technique is not perfect.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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