Medication Information Leaflet


What is this medicine used for

Montelukast prevents swelling of the airways and is used to prevent and treat asthma and allergic rhinitis. It can also be used for other conditions as determined by your doctor.

Related: Asthma

How should I take/use this medication?

  • Take exactly as how your healthcare professional has told you.
  • Do not stop taking your medication without checking with your healthcare professional.
  • You may take this medication with or without food. 
  • If you are taking montelukast granules, it can be mixed with a spoonful of cold or room temperature soft food, such as ice cream, rice or steamed carrots. The medication must be taken within 10 to 15 minutes after the medication packet is opened. You should not dissolve the granules in water, but you can drink water to help swallow down the granules.
  • If you are taking the montelukast chewable tablets, chew well before swallowing.

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if: 
  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, planning to become pregnant, or breastfeeding.
  • You are taking any other medications, including supplements, traditional medications and herbal remedies. 

What are some side-effects that I need to seek medical advice immediately?

In very rare cases, some patients might experience the following:
  • Mood and behaviour changes such as nightmares, dreams that are not normal, trouble sleeping, feeling irritated, feeling restless or anxious
  • Flu-like symptoms such as fever, cough and sore throat
  • Pins and needles or numbness in arms or legs
  • Worsening lung issues 
The symptoms of a drug allergy include one or more of the following: 
  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body
If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What are some other side-effects of this medication?

The side effects for montelukast is usually mild and generally well tolerated. They include the following: 
  • Sore throat
  • Infection of the airways
  • Stomach pain, diarrhoea, nausea
  • Headache
  • Feeling tired
  • Skin rashes
These symptoms may happen but should get better over time. Check with your doctor if any of these symptoms are serious or do not go away.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore.

Last updated on July 2019


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