Topical Fluorouracil

Medication Information Leaflet

What is this medication for?

Topical fluorouracil is used on the skin to treat skin cancer and skin conditions that could become cancerous. Fluorouracil interferes with the growth of abnormal cells which are eventually destroyed.

This medication is also used for other skin conditions as determined by your doctor.

How should I take/use this medication?

  • Before you apply this medication to the skin, clean the affected area and dry well.

  • Wait for 10 minutes, then apply a small amount of medication to the affected skin.

  • The medication should be applied in a thin layer to the affected area and its surrounding (determined by the doctor) once or twice daily or as advised by your doctor.

  • The total area of skin treated at any one time should not be more than 23x23 cm (500 cm2) or 9x9 inches.

  • Do not cover the area with a bandage unless directed by your doctor.

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

If you miss a dose of this medication, apply it as soon as possible. However, if it is almost time for your next application, skip the missed application and carry on as before. Do not apply a double dose.

What precautions should I take?

  • Be careful if you are applying the medication around your eyelids, nose and lips and avoid any contact with the eyes or mouth. Wash your hands thoroughly after use.

  • Do not apply the medication on open wounds.

  • If somebody else is helping you to apply the medication, they should take precautions to avoid the medication being absorbed through their skin. It is recommended that they should wear disposable surgical gloves, remove them after use and wash their hands thoroughly.

  • Inform your healthcare professional if:

    • You are allergic to this medication or any of the other ingredients of this medication.

    • You have any red/irritated/open sores on your skin.

    • You are pregnant, planning to become pregnant, or breastfeeding.

What are some common side-effects of this medication?

Certain side effects of this medication are not unusual and may even disappear during treatment. If any of the following effects persist or are severe, consult your doctor.

  • Redness, soreness, scaling and peeling of affected skin

    • This is to be expected. It happens within 1 or 2 weeks of use and may last for several weeks even after you have stopped using the medication. Sometimes a pink, smooth area is left when the treated skin heals. This area will usually fade after 1 to 2 months. Do not stop using this medication without first checking with your doctor.
  • Skin irritation, burning, pain and swelling at the site of application

  • Enlarged lymph nodes may appear transiently

  • This medication may make you more sensitive to the sun

    • Avoid prolonged sun exposure, tanning booths, and sunlamps. Use a sunscreen and wear protective clothing when outdoors.

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

  • Stomach pain
  • Severe or bloody diarrhoea
  • Vomiting
  • Vision changes, eye pain or severe eye irritation
  • Mouth sores
  • Fever, chills, or sore throat; unexplained bruising or bleeding; feeling very tired or weak
  • Symptoms of a drug allergy: 
    • 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?

Do check with your healthcare professional if you are taking any other medications or applying any other medications on the skin being treated.

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 the medication into a bag and bring it back to the pharmacy where you received the medication from.


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 March 2021

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