Steroid inhalers, also called corticosteroid inhalers, are anti-inflammatory sprays or powders that you breathe in.
Steroid inhalers are only available on prescription. Common types include beclometasone, budesonide, fluticasone and mometasone.
They're sometimes called "preventer inhalers" because they can help prevent your symptoms.
This page covers:
Who can use them – including pregnancy advice
There are several types of steroid inhaler, which are used in slightly different ways.
A doctor or nurse will show you how to use your inhaler. Make sure you use it exactly as advised. The Asthma UK website has videos explaining how to use the different types of inhaler.
You'll usually need to take one or two puffs from your inhaler in the morning and one or two puffs in the evening.
It's important to keep using your inhaler, even if you feel better. It will only stop your symptoms if it's used every day.
If you forget to take a dose, take it as soon as you remember. If it's nearly time for your next dose, skip the one you missed.
Don't take a double dose to make up for a forgotten one.
Accidentally taking too many puffs from a steroid inhaler is unlikely to be harmful if it's a one-off. Speak to your doctor, nurse or a pharmacist if you're worried.
Using a steroid inhaler too much over a long period can make you more likely to get side effects.
Don't stop using your inhaler unless advised to by your doctor.
When you stop your treatment, you usually need to reduce your dose gradually.
Steroid inhalers usually cause few or no side effects if used correctly and at normal doses.
Some people get:
If you're taking a high dose for a long time, there's also a small chance you could get some of the side effects associated with steroid tablets, such as an increased appetite, mood changes and difficulty sleeping.
You can report any suspected side effect to a UK safety scheme.
The following tips may help reduce the side effects of steroid inhalers:
If you're taking a high dose for a long period of time, you may be given a special steroid treatment card that explains how you can reduce the risk of side effects.
Some medicines can interfere with the way steroid inhalers work, but this is uncommon if you're only taking low doses for a short period.
Tell your doctor if you take any other medicines, including herbal remedies and supplements, before starting to use a steroid inhaler.
If you're already using an inhaler, ask your doctor or a pharmacist for advice before taking any other medicines, remedies or supplements.
You can usually drink alcohol while using a steroid inhaler and you should be able to eat most foods. Don't smoke, though, as this can make your medicine less effective.
Most people can use steroid inhalers.
Tell your doctor before starting treatment if you:
Steroid inhalers are normally safe to use while breastfeeding and during pregnancy, but it's a good idea to get medical advice first.
If you need to take a high dose during pregnancy, you may need regular check-ups to check for any side effects.
Steroids are a man-made version of hormones normally produced by the adrenal glands, two small glands found above the kidneys.
When they're inhaled, steroids reduce swelling (inflammation) in your airways.
This can help reduce symptoms of asthma and COPD, such as wheezing and shortness of breath.
Steroid inhalers are different to the anabolic steroids used by athletes and body builders to improve their performance.