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Montelukast: uses, benefits and side effects

January 20th, 2019 by Joe Lofts

Quick facts

What is montelukast?

Montelukast (mon-te-LU-kast) is a medicine that can be prescribed as an ‘add-on’ treatment for asthma if your condition isn't fully controlled by using a regular corticosteroid inhaler. It is used to prevent wheezing, chest tightness, coughing and shortness of breath caused by asthma, and to reduce the frequency of asthma attacks.

The medicine can also be used to relieve symptoms of hay fever (allergic rhinitis), such as sneezing and an itchy or runny nose.

Montelukast is available on prescription and comes in the form of film-coated tablets.


How does montelukast work?

Montelukast belongs to a class of drugs called leukotriene receptor antagonists (LTRAs). It works by blocking the action of substances in the body that cause the symptoms of asthma and allergic rhinitis.

Montelukast blocks the effect of chemicals called leukotrienes, which are released during an allergic or inflammatory reaction and can cause the airways to become inflamed. For people with asthma, leukotrienes are released in the lungs, causing inflammation, narrowing in the airways and increased mucus production. Montelukast blocks the action of these leukotrienes, which, in turn, reduces the symptoms of asthma. 

Echo 's Social Media Manager, Manpreet, has had asthma since the age of 2 and takes montelukast to help control her condition. She said:

"I was given this as part of my treatment alongside my Relvar preventer inhaler. It was given to me to control my asthma, and I take one tablet in the evening before I go to bed. Not only does it help control my asthma during the nighttime, when it normally gets worse, but it has also controlled my asthma until the early morning. Though I didn't notice an immediate effect when it started taking it, I did realise that in the long run it reduced the number of asthma attacks I was having at night and allowed me to be able to control my breathing."

Montelukast does not work straight away, so should not be used to treat sudden asthma attacks or other breathing problems that come on rapidly. Unlike an inhaler, LTRAs such as montelukast are not steroid based.

Montelukast dosage information

Montelukast tablets come in three different strengths: 4mg, 5mg or 10mg. The dose will depend on your symptoms, your age, and any other factors your GP may take into consideration.

Montelukast for asthma

For children aged 6 months to 5 years, the recommended daily dose is 4mg taken once in the evening. For children aged 6 to 14 years, the usual dose is 5mg taken once in the evening. For children aged 15 to 17 years and adults, the usual dose is 10mg, again to be taken once in the evening.

Montelukast for hay fever (allergic rhinitis)

Montelukast is only prescribed to those aged 15 and over for hay fever relief. The recommended daily dose is 10mg to be taken once in the evening.

You can find instructions in your medicine’s Patient Information Leaflet if you are uncertain about your montelukast dosage. Alternatively, your GP and pharmacist are on hand to provide advice.


How to take montelukast

Montelukast can be taken with or without food. Do not crush, break or chew the tablets - take them whole with a glass of water.

If you accidentally miss a dose, do not take two tablets to make up for the forgotten dose. Instead, wait for the next dose. Using Echo can help you keep on top of your doses.

You should take the tablets every day, even if your symptoms have started to clear up. If you want to stop treatment, do not abandon the medication suddenly. Speak to your GP about gradually decreasing your dose, as this will reduce the risk of developing rebound allergy symptoms.

Montelukast should never be taken to treat an asthma attack because it won’t work. Asthma attacks need to be treated with reliever inhalers (e.g. Ventolin/salbutamol) that quickly open up the airways. If you have asthma, make sure you always have your reliever inhaler at hand.

Montelukast side effects

As with any medicine, it’s possible that montelukast may cause side effects in some people. Common side effects affect less than 1 in 100 people and include:

These side effects are usually mild and will go away after a couple of days. If they are severe or continue to persist for a week or more, contact your GP or pharmacist.


Serious side effects are rare. Contact a doctor immediately if you start to experience any of the following:

For a full list of montelukast side effects, check your Patient Information Leaflet.

Montelukast interactions

Before you start taking montelukast, it’s important to tell your GP or pharmacist about any other medications, herbal remedies or supplements you are taking. You should also check with your GP before taking any other medicines while you’re on montelukast to make sure the combination is safe.

Check out the NICE website for a comprehensive list of interactions with montelukast. If you’d like more information on possible montelukast interactions, speak with your GP or pharmacist.

Montelukast contraindications

If you’re concerned about your suitability to montelukast, speak with your GP or pharmacist.

Taking montelukast during pregnancy or while breastfeeding

Follow up with your GP for further advice if you become pregnant or are breastfeeding while taking this medication.

What’s the easiest way to get montelukast?

If you have been approved to take montelukast on repeat prescription by your GP, there's no need to find the time to run to a pharmacy. When you request through the Echo app, you can have your medication delivered to an address of your choice via Royal Mail, free of charge. We'll even remind you when to take it and when to reorder.


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Clinically reviewed by Pooja Raichura MRPharmS: 9/1/18

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