Preventer inhalers used in asthma work to gradually reduce inflammation and sensitivity of the airways. If taken correctly they reduce the severity of asthma symptoms day to day and reduce the number and severity of asthma flare-ups a patient might have. They require more commitment because, if they are to work, they need to be taken regularly every day.

They are used to treat lung conditions where there is inflammation and sensitivity of the airways. This includes common conditions such as Asthma.

With regular use they work to gradually reduce the sensitivity of the airways and reduce inflammation to get a patient's asthma symptoms under control.

Preventer inhalers can have one or two types of medicine in them. In milder cases a preventer with a inhaled steroid is usually used by itself. This can then be increased to a stronger steroid or to a combination of an inhaled steroid plus a medicine that helps the airways relaxed which is a longer acting version of salbutamol.

The dose needed really depends on the patient's symptoms - both the severity and frequency of symptoms. In milder cases a preventer inhaler with a low dose of inhaled steroid may be enough, but in more severe cases patients may need a higher dose of inhaled steroid with the longer acting version of salbutamol.

The commonest side effects of preventer inhalers are sore throat or hoarse voice. The preventer inhaler can also make it more likely for a patient to develop an oral thrush infection.

It is really important to avoid a poor technique when taking your inhaler. There are lots of videos online to show you the best way to take the inhaler to maximise the amount of medicine reaching the lungs. Ensuring a good inhaler technique can also reduce some of the common side effects.

Long term use of steroids can have side effects so it is important to be on the lowest dose that controls your symptoms. Long term steroid use can contribute to problems such as cataracts and slightly reduced growth in children (but this should be closely monitored).

There are some cases where alcohol can trigger asthma symptoms. Some patients find that the preservatives in drinks such as wine can also worsen there asthma.

The decision to use in pregnancy needs to take into account the expected benefit for the mother and any possible harms to the baby.

The British National Formulary recommends that inhaled asthma medications are taken as normal during pregnancy.