Preventer inhalers

Taking your preventer inhaler every day even when you're feeling well cuts down asthma symptoms

How do preventer inhalers help asthma?

An asthma preventer inhaler prevents inflammation and swelling in your airways.

It helps the medicine get right into your airways so it can get to work where it’s needed.

If you use your preventer inhaler every day as prescribed, using a good inhaler technique, your airways will be less sensitive. This means you'll be less likely to react to your usual asthma triggers.

Because your preventer inhaler helps stop symptoms coming on in the first place, you may notice you don't need to use your reliever inhaler as much.   

To get the full benefits, you need to take your preventer inhaler every day as prescribed (usually morning and evening) even when you're feeling well.

This is because the protective effect of the preventer inhaler builds up over time. 

What kinds of asthma preventer inhalers are there?

There are several different types of preventer inhaler. They all contain a low dose of steroid medicine to reduce inflammation. 

The steroids used to treat asthma are called corticosteroids. These are a copy of those produced naturally in our bodies. They are completely different to the anabolic steroids associated with bodybuilders and athletes.

Preventer inhalers are often brown. They include: 

  • Metered dose inhalers (MDIs) which give the medicine in a spray form (aerosol). This is the one you often use with a spacer. 
  • Breath actuated inhalers (BAIs) which automatically release a spray of medicine when you begin to inhale (breathe in).
  • Dry powder inhalers (DPIs) which give the medicine in a dry powder instead of a spray.

Whatever inhaler you're prescribed, you need to know how to use it in the best way.  

A good inhaler technique helps get the asthma medicine into your lungs, so you can get the full benefits. 

Spacers make MDIs easier to use because you don't have to worry about getting the timing right for pressing the inhaler and breathing in. 

Does everyone with asthma need a preventer inhaler?

There are very few people who only need a reliever inhaler for when they get symptoms.

Most people with asthma benefit from a regular preventer inhaler taken every day to prevent symptoms coming on.

This is because preventer medicine, taken as prescribed, builds up your asthma protection over time and helps prevent asthma symptoms.  

Your GP will prescribe a preventer inhaler if:

  • your asthma is not in good control - one sign of this is that you need to use your reliever inhaler three times a week or more
  • you're breathless, coughing or have a tight chest during everyday activities three or more times a week
  • your sleep is disturbed by cough or a tight chest each week

Some people are prescribed a preventer inhaler for seasonal use if their symptoms are related to hay fever (seasonal allergic rhinitis).

"If you get hay fever which triggers your asthma, you should ideally start taking your preventer inhaler two weeks before the pollen you're allergic to comes into season," says our Head of Helpline, Sonia Munde. "You then need to take it regularly while that pollen is in season."

What benefits can I expect from my preventer?  

If you take your preventer inhaler as prescribed, you'll soon start to notice the benefits. For example, you might notice: 

  • you're less sensitive to your triggers, such as cigarette smoke and colds and flu, because your airways are less inflamed
  • you're able to climb stairs or walk up hills more easily
  • you're sleeping better, and not coughing at night
  • you or your child need less time off work or school
  • you're more able to take part in exercise and family activities.

You won't notice these improvements straight away. But if you keep taking your preventer inhaler as prescribed, and continue to take it even if you feel well, all these benefits could start to feel just part of every day life. 

How do preventers help with asthma triggers?

A trigger is anything that sets off your asthma symptoms or makes symptoms worse. Common triggers include dust, pollen, animals, colds and flu and cold weather.

You may sometimes be able to avoid triggers, but it's not always possible. 

Using your preventer inhaler every day as prescribed makes your airways less likely to react to any triggers you come across.  

Your preventer inhaler contains a dose of steroid medicine which you breathe in. It controls the inflammation and swelling in your airways and makes them less sensitive to your triggers. 

It’s also important to go for your regular asthma reviews. Your GP or asthma nurse can check you’re on the right dose of preventer medicine to prevent symptoms when you’re around triggers.   

When do I need to take my preventer inhaler? 

You need to take your preventer inhaler every day as prescribed, usually morning and evening. 

Take it even if you're feeling well and aren't getting any symptoms. This is because the protective effect of the medicine builds up over time. And if you stop taking your preventer inhaler for several days at a time the protection will wear off.

Get the best from your preventer inhaler by:

  • getting into a good routine. Keep your preventer inhaler somewhere that reminds you to take it. Or try a reminder app on your phone. Sticking to a good routine makes taking your inhaler an every day habit like brushing your teeth.
  • talking about it at your annual asthma review. A regular asthma review gives you the chance to talk about the medicines you're taking for your asthma. You can discuss whether you need to increase the dose of your preventer medicine. Or if you can lower the dose.
  • using your inhaler correctly. Your GP, asthma nurse or pharmacist can check your inhaler technique. And always watch your child take their preventer inhaler so you can make sure they're using it correctly.
  • taking it even when you feel well. We know people often worry about taking medicines when they don't have any asthma symptoms. But if you stop taking it, your symptoms may come back. If you do feel well and you've been taking your preventer inhaler as prescribed it's a good clue that your medicine is working and will continue to work if you keep taking it.

 “When I took myself off my preventer inhaler it's because I thought I was better, but in fact I was only better because I had been taking it. Now that I’m using my inhaler again, I am keeping myself well and managing my asthma.”  Loren, who has had asthma for twenty years.

Why you still need your reliever inhaler too 

If you're prescribed a preventer inhaler, it doesn't mean you should to stop carrying your blue reliever inhaler wherever you go.

Although they have different jobs, you need both a preventer and a reliever to control your asthma.   

  • A preventer inhaler prevents inflammation and sensitivity in your airways over time. This means if you take your preventer inhaler every day as prescribed, you're less likely to react to triggers and get asthma symptoms such as breathlessness. A good routine of taking your preventer inhaler can help cut your risk of an asthma attack.
  • A reliever inhaler relieves symptoms when they come on. It acts quickly when you have an asthma attack but it doesn't do anything about the inflammation building up in your airways. Everyone who has asthma should have a reliever inhaler and have it with them at all times.

If you find you need to take your reliever inhaler three times a week or more it may be a sign that your asthma's not well controlled. You need to book an appointment with your GP or asthma nurse so you can review your treatment. 

What are the possible side effects of preventer inhalers?

Most of us have some concerns about possible side effects from the medicines we take. But recent research shows that the chances of side effects from taking a low dose of inhaled preventer medicine are very small.  

It's worth remembering that the preventer dose will be kept as low as possible to protect you or your child against the inflammation that causes asthma symptoms.

And using your preventer inhaler every day as prescribed, means you're less likely to need your reliever inhaler, or a prescription of oral steroid tablets - with higher doses of steroids.  

Some of the more common side effects are:

  • a sore throat
  • a hoarse voice
  • a mouth infection called thrush.

You can avoid these side effects by making sure your medicine gets straight to your lungs and doesn't stay in your mouth and throat, or get absorbed into the rest of the body.

You can do this by:

  • using a spacer with your MDI inhaler
  • using good inhaler technique (you can ask your GP or asthma nurse to check your inhaler technique at your asthma reviews)
  • rinsing your mouth and spitting out 
  • brushing your teeth after using your inhaler. 

If you're worried about your child taking asthma medicines read our expert answers to your common concerns.  

Other possible side effects

It is possible that using high doses of inhaled steroids over a long period of time may cause some other side effects.

For example:

  • some studies show that older people who have used inhaled steroids for some time at quite high doses have a very slight risk of developing cataracts.
  • there's a small link between the long-term use of inhaled steroids and very slightly reduced growth - clinically described as 'insignificant'. This is why your GP or asthma nurse may suggest checking your child's height and weight at their asthma review.

In most cases your GP will try to reduce any risk by always using the lowest possible dose of medicine to control the condition.  

This is why it's so important to go for an asthma review at least once a year to make sure you're taking the right medicines for you.

It's always worth remembering that with the added protection of a preventer medicine you're less likely to need to use your reliever inhaler or to have an asthma attack needing higher dose oral steroid tablets to get your asthma back in control.

Weighing up the benefits

Whatever medicines we're taking, it's often helpful to weigh up the risks versus the benefits.

  • Asthma attacks kill three people every day in the UK. Almost half of these could have been prevented with better routine care, such as taking a regular low dose preventer inhaler every day.
  • The risk of side effects from taking your asthma preventer inhaler as prescribed is much smaller than the risk of a potentially life-threatening asthma attack. 

We don't always feel comfortable taking medicine when we feel well; it makes more sense to us to take it when we've got symptoms.

But a preventer inhaler is only effective if it is taken as prescribed and discussed with your GP or asthma nurse, even when you're feeling well.

You could be symptom-free if you stick to your preventer medicine routine.Your GP or asthma nurse will always try to keep you on the lowest dose possible to control your symptoms.

Last updated April 2018

Next review due August 2021