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How and when to take montelukast - Brand name: Singulair

Always follow your doctor's instructions about how and when to take montelukast.


Montelukast comes as 10mg non-chewable tablets, chewable tablets in strengths of 5mg or 4mg, and granules in sachets of 4mg.

The usual dose for adults and children aged 15 years old and over is one 10mg tablet once a day.

The usual dose for children aged 6 to 14 years old is one 5mg chewable tablet once a day.

The usual dose for children from 6 months to 5 years old is 4mg once a day. This can be taken as granules, or a chewable tablet for children over 2 years old.

How to take it

Most people take montelukast once a day in the evening to prevent symptoms of asthma or allergies. However, if exercise makes your asthma worse, your doctor might tell you to take montelukast 2 hours before you exercise.

Never take more than 1 dose a day.

How to take non-chewable tablets

You can take montelukast non-chewable tablets with or without food.

Swallow the tablets whole with water, juice or milk. Do not chew these tablets.

How to take chewable tablets

It's important to take chewable tablets at least 1 hour before food, or 2 hours after food. This is so the medicine is absorbed into your body properly.

Chewable tablets can be chewed or sucked. You or your child can have a drink of water or squash afterwards.

How to give granules to a child

Montelukast granules come in a sachet with 4mg of granules inside (one dose). You can put them directly on your child's tongue. You can also mix the granules with a spoonful of cold, soft food, such as yoghurt or ice-cream.

Make sure your child takes the whole dose immediately (or within 15 minutes).

It's important not to dissolve the granules in a drink. You can give your child a drink afterwards.

How long to take it for

Take montelukast for as long as your doctor recommends it. It will only keep working while you're taking it.

Do not stop taking montelukast without speaking to your doctor first, because your symptoms may get worse.

If you forget to take it

If you or your child miss a dose of montelukast, skip the missed dose and take your next dose the following day at the usual time.

Do not take 2 doses to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you. You could also ask a pharmacist for advice on other ways to help you remember to take your medicine.

If you take too much

Urgent advice: Contact 111 for advice if:

  • you take more than your prescribed dose of montelukast

Go to or call 111. Call 111 if you're asking about a child under the age of 5 years.

If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.

Take the montelukast packet or leaflet inside it, plus any remaining medicine with you.

Page last reviewed: 14 March 2023
Next review due: 14 March 2026