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How do inhalers work?

Millions of us use inhalers in the UK. For some, they're a lifesaver. For others, they provide welcome relief. For others still, they're more of a security blanket to be carried around in the bottom of the handbag just in case.

Inhalers deliver medicine you need straight to your lungs. It goes without saying then, that they're used for conditions which affect your lungs, of which by far the most common are asthma and chronic obstructive pulmonary disease (COPD).

Because the medicine goes straight to where it's needed, you only need tiny amounts compared to the dose you'd need to take of the same medicine in tablet form. That means fewer side effects and more effective treatment - as long as you take them properly.


The wheeze and cough of asthma affect one in 20 adults and one in 10 children. Which inhalers you'll get depends on how severe, and how frequent, your symptoms are - but the aim is to keep you pretty much wheeze-free, so you only need to take a dose of 'reliever' medicine every few days at most to live a completely normal life.


In the early stages, you may only need an occasional dose of reliever medicine. As time goes on - especially if you keep smoking - you may find your ability to exercise becomes more limited. Once this happens you'll need to start taking regular inhalers. However, inhaled medicine will still help, even if your lungs aren't as young as they were.

Reliever inhalers

Reliever inhalers open up the airways in asthma and COPD . This means air can flow more freely into your lungs, relieving wheeze and breathlessness. They start to work within minutes but their effect usually only lasts a few hours.

If your asthma is well controlled, you should only need your reliever inhaler occasionally - perhaps when you're exercising or when you have a cold. The inhalers are often blue and common ones include Ventolin® (salbutamol) and Bricanyl® (terbutaline).

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Preventer inhalers

Preventer inhalers don't work as fast as relievers, but they're just as important. If your symptoms aren't controlled by using occasional puffs of your reliever medicine, you'll be advised to take a preventer inhaler to stop symptoms happening in the first place. Different ones work in different ways, but their roles include reducing inflammation in the airways and opening the airways up.

They need to be taken every day for full effect, and can both prevent wheeze and improve your ability to get around and exercise. They can also reduce your risk of a severe attack needing hospital admission. In asthma, the most common preventer inhalers contain small doses of steroid. You may also get a long-acting version of a reliever medicine to take to relieve your symptoms over 12 or even 24 hours.

Types of inhaler device

As if treatment with relievers and preventers weren't complicated enough, there are different devices to deliver the medicine into your lungs, and sometimes the same medicine comes in several different devices. Some devices involve pressing down and breathing in at the same time.

These are called 'metered dose inhalers' and are among the most common type of inhaler used to deliver reliever medication in particular. Sometimes with these metered dose inhalers, your doctor or nurse will recommend that you pump a dose of medicine into a plastic bubble and breathe it in from here.

Others still are 'breath-actuated' - as you breathe in, the medicine is delivered automatically into your lungs. Fortunately your practice nurse or GP can help you find the right one for you.

Even if you've had asthma or COPD for a long time and have used the same inhaler for years, it's still worth reminding yourself regularly how they work. You might be surprised how different the 'optimal' inhaler technique is from your own!

The right inhaler technique

If your inhaler technique isn't good, you may not be getting much of the medicine into your lungs at all. Problems often arise with the metered dose inhalers, where you have to co-ordinate pressing down to get the dose at the same time as you breathe it in.

If you press before you breathe, most of the dose ends up on the back of your throat rather than in your lungs. Press after you breathe in and you'll leave it all in your mouth where it will promptly get breathed out again!

If you've been given a spacer to use with your metered dose inhaler and don't use it, you'll get up to 30% less medicine going into your lungs but more going into your body because it's deposited in your mouth and throat. That makes you more prone to side effects, such as trembling and palpitations from large doses of reliever medication.

If you're in any doubt, take your inhaler with you when you get your next check-up with the doctor or nurse and get them to look at how you take it. Alternatively, many pharmacists now have training in checking inhaler technique.

Nebulisers - a better option?

Although nebulisers are sometimes used in hospital to get high doses of inhaled medicine into your lungs in severe asthma attacks, the British Thoracic Society (BTS) says there's not enough evidence to recommend them for routine use.

What's more, the BTS now recommends using a metered dose inhaler with a spacer rather than a nebuliser in mild to moderate asthma attacks. That means that for children in particular, you may find the doctor gives them a spacer and not a nebuliser when they're acutely wheezy. Don't worry - there is good evidence the spacer will work just as well in these cases.

With thanks to 'My Weekly' magazine where this article was originally published.

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