Ketotifen (Oral)

Ketotifen is used for relieving symptoms of allergic conditions such as sneezing, runny nose, itchy and red eyes, skin rashes or hives. It can also be used to prevent asthma in children. Learn how to use the medication, side effects, special precautions, and more.

What is this medication for?

Ketotifen is used for relieving symptoms of allergic conditions such as sneezing, runny nose, itchy and red eyes, skin rashes or hives. It can also be used to prevent asthma in children. However, it is not effective for use in an acute asthma attack. 

Ketotifen belongs to a group of medications called antihistamines. It works by blocking the effects of histamine, a chemical that causes allergic symptoms. When used for the prevention of asthma, it may take several weeks before you can notice any improvement in symptoms. 

How should I take/use this medication?

  • Take this medication when necessary to relieve your symptoms.
  • You may take this medication with or without food.
  • When taking it regularly for prevention of asthma, do not stop taking your medication without checking with your healthcare professional.
  • For the oral solution, shake the bottle well before use.

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. 
If you are taking it only on a “as-needed” basis; there is no need to take the medication if you are not experiencing any symptoms. 

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.
  • You have epilepsy or known history of seizure.
  • You have diabetes or are taking any oral medications for diabetes such as metformin.

What are some common side-effects of this medication?

  • Drowsiness or dizziness
    • Avoid driving, operating machinery or other activities which require concentration while on this medication.
  • Dry mouth, skin and eyes
    • Drink more water or suck an ice cube to help with mouth dryness.
    • Use moisturising eye drops to resolve eye dryness.
  • Difficulty sleeping, irritability, feeling nervous, agitation, excitation
  • Increased appetite, weight gain

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

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 food or medication should I avoid when I take this medication?

Ketotifen may interact with oral blood sugar lowering medications (e.g. metformin), antihistamines (e.g. promethazine) and medications that may cause drowsiness. You should not drink alcohol while taking Ketotifen as it may worsen the drowsiness.

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 it into the rubbish chute or bin. 



Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

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. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on April 2024

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