Preventer inhalers

Find out how preventer inhalers help reduce your chances of having asthma symptoms.

Preventer inhalers in brief:

  • Some people with asthma are prescribed a preventer inhaler. They help prevent asthma symptoms by reducing swelling and inflammation in the airways.
  • There are several kinds of preventers. They usually contain a low dose of steroid medicine called corticosteroids.
  • Taking your preventer inhaler regularly, usually twice a day, means you're less likely to have asthma symptoms, or asthma attacks.
  • You should use it even if you're feeling well because the protective effect builds up over time.
  • Your GP, asthma nurse or pharmacist should show you how to use your inhaler properly so that every dose is effective.
  • Your preventer inhaler will not help during an asthma attack. Keep your fast-acting reliever inhaler (usually blue) with you at all times so you can use it if you have any asthma symptoms, such as coughing, wheezing, shortness of breath and tightness in the chest.

How do preventer inhalers help asthma?

A preventer inhaler is a device that helps the medicine get right into your lungs so it can work where it's needed to prevent and reduce the swelling and inflammation in your airways.

The protective effect of the preventer inhaler builds up over a period of time so preventers need to be taken every day (usually morning and evening) even when you're feeling well.

Try keeping a symptom diary to help you notice any changes or improvements.

What kinds of preventers are there?

There are several kinds of preventers, but they all work in a similar way and usually 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.

  • Metered dose inhalers (MDIs) give the medicine in a spray form (aerosol).
  • Breath actuated inhalers (BAIs), such as Easi-breathe and Autohaler, automatically release a spray of medicine when you begin to inhale.
  • Dry powder inhalers (DPIs), such as Turbohaler and Accuhaler, 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. Good inhaler technique helps get as much of the asthma medicine into the lungs as possible. To make it easier to get the best from your asthma medicine, aerosol inhalers can be used with a spacer.

Not everyone with asthma will be prescribed a preventer inhaler

Sometimes when you're diagnosed with asthma you start off with just a reliever inhaler but you may be prescribed a preventer inhaler later on. If you or your child has asthma symptoms regularly, your GP or asthma nurse may decide that the best form of treatment is a preventer inhaler because this builds up your asthma protection over time.

Preventer inhalers are usually prescribed when:

  • 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 occasional use if their symptoms are related to hay fever (seasonal allergic rhinitis). "If you get hay fever which triggers your asthma, you should start taking your preventer inhaler ideally 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 kind of benefits can you expect?

If you take your preventer inhaler regularly as prescribed, one thing you'll notice is that you'll be less sensitive to your triggers, such as cigarette smoke and viral infections, because your airways are less inflamed.

You might notice you're able to climb stairs or walk up hills more easily, that you're sleeping better, and not coughing at night. You might also notice that you or your child need less time off work or school and that 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, these improvements will just become part of your everyday life and you or your child could be symptom-free.

How does my preventer inhaler help me manage my 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 – for example, by exercising indoors when it’s very cold, or by staying away from houses that have pets, if you react to them. But in reality, it’s often impossible to keep away from all your triggers. What you can do instead is reduce the risk of triggers setting off your symptoms.

Using your preventer inhaler as directed is one of the most important ways of doing this. Your preventer inhaler contains a dose of steroid medicine that controls the inflammation and swelling in your airways.

This medicine makes your airways less likely to react to any triggers you do come across. It’s also important to go for your regular asthma reviews, where your GP or asthma nurse will make sure you’re on the right dose of preventer medicine to help stop symptoms when you’re around triggers.   

When to take your preventer inhaler

You need to take your preventer inhaler every day as prescribed, usually morning and evening, even if you're feeling well. This is because the protective effect of the medicine builds up over time.

Once this protection is working, occasionally forgetting to take your inhaler won't usually cause a problem. But if you forget or stop for several days at a time this will mean your protection begins to disappear. If you stop using your preventer inhaler, being exposed to any of your asthma triggers is more likely to bring on an asthma attack.

Get the best from your preventer inhaler

  1. Help yourself get into a good routine by keeping your preventer inhaler somewhere to help you remember to take it - on your bedside table so it's there in the morning and at night, for example. Put a note up somewhere to remind you or programme a reminder app on your smartphone. Eventually taking your inhaler will become as much as a habit as brushing your teeth every morning and evening.
  2. Use your inhaler in the best way - your GP, asthma nurse or pharmacist should explain how to use your inhaler so that every dose you take gives you the most benefit and make sure the device you're using is the right one for you. Always watch your child take their preventer inhaler so you can make sure they're doing it in the right way and not getting into bad habits, such as taking their inhaler in a rush as they get ready for school or not taking it at all.
  3. Take it even when you feel well. We know that people often worry about taking medicines when they don't have any asthma symptoms. But your preventer medicine is designed to help you stay well rather than give you on-the-spot relief. It works in a different way to your reliever and can help improve your asthma over the long term. 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.
  4. Discuss it at your annual asthma review. As your symptoms improve, your GP or asthma nurse might suggest you take fewer daily puffs or move you to a lower strength inhaler. A regular asthma review gives you the chance to look at what medicines you need for your asthma and discuss with your GP or asthma nurse if you can lower the dose.

Possible side effects of preventer inhalers

Many of us are worried about side effects from the medicines we take. But recent research has shown that the chance of side effects from taking a low dose of inhaled preventer medicine is 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 that you're less likely to need your reliever inhaler or a prescription of oral steroid tablets which will mean 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
  • finding out if your medicine is available to take in a Breath Actuated Inhaler which can reduce side effects without the need of a spacer
  • using good inhaler technique
  • rinsing your mouth out and brushing your teeth after using your inhaler - try keeping your preventer inhaler in the bathroom so you get into a routine of taking it before you brush your teeth.

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 people over the age of 49 who have used inhaled steroids for some time at quite high doses have a very slight risk of developing cataracts.

In most cases any risk can be reduced by always using the lowest possible dose of medicine to control the condition. Your GP or asthma nurse will always try to keep you on the lowest dose possible to control your symptoms.

Your child will always have their height and weight checked at their asthma review. This is because there's a small link between the long-term use of inhaled steroids and slightly reduced growth.

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 regular preventer medicine is much smaller than the risk of a potentially life-threatening asthma attack if you're not taking the right medicines.

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 only works if it is taken regularly, as prescribed, even when you're feeling well. You could be symptom-free if you stick to your preventer medicine routine.

Last reviewed March 2016