Fluorouracil (Efudix)

How does it work?

Efudix cream contains the active ingredient fluorouracil, which is a type of medicine known as a cytotoxic antimetabolite. Fluorouracil is a chemotherapy medicine used to treat cancer. Efudix cream is applied to the skin to treat skin cancer and skin conditions that can develop into cancer (pre-malignant skin lesions).

Cancers form when cells within the body multiply abnormally and uncontrollably. These cells spread, destroying nearby tissues. Fluorouracil works by stopping cancerous and pre-cancerous cells from multiplying. It does this by being incorporated into the cells' genetic material, DNA and RNA. Both DNA and RNA are needed for cells to grow, repair themselves and multiply. Fluorouracil causes problems with the production of DNA and RNA in the cancerous cells and this causes them to grow in an unbalanced way, resulting in the death of the cells.

Fluorouracil cream will cause the area of the skin being treated to become red, blotchy and inflamed. This will probably be followed by some discomfort, skin erosion and eventually, healing. Healing may not be complete until one or two months after you stop using the cream. The cream should not damage normal healthy skin. However, Efudix will treat abnormalities of the skin that were not previously visible to the naked eye, and these abnormalities may become red and inflamed.

If your skin causes you a lot of discomfort during the treatment you should tell your doctor, as this can usually be eased by using a corticosteroid cream.

What is it used for?

  • Superficial malignant skin cancers.
  • Skin conditions that are not cancerous but may eventually lead to skin cancer if left untreated (pre-malignant skin lesions).

How do I use it?

  • This medicine is for external use on the skin only, under specialist medical supervision.
  • It is important not to use too much cream. Efudix cream should not be used to treat areas of skin that are larger that 23cm x 23cm (9 x 9 inches) at one time. Larger areas should be treated in stages, one section at a time.
  • Efudix cream should be applied thinly and evenly to the affected area(s) of skin once or twice a day, as directed by your doctor.
  • The cream should not be applied to broken skin or open cuts as it may be absorbed into the bloodstream and could cause side effects.
  • Wash your hands after applying the cream to avoid inadvertently transferring it to other areas.
  • You may be advised to apply a dressing to the area of skin being treated. Follow the instructions given by your doctor.
  • The cream is usually used for three to four weeks initially. Lesions on the face usually respond more quickly than those on the trunk or lower limbs, while lesions on the hands and forearms respond more slowly. Again, follow the instructions given by your doctor.


  • Take extra care to avoid getting the cream in the eyes or mouth, particularly if you are using the medicine on your face.
  • Sunlight can increase the intensity of the skin reactions to Efudix cream. For this reason you should avoid exposing your skin to direct sunlight as much as possible while using the cream. Do not use sunbeds or sunlamps.

Use with caution in?

  • People with reduced activity or deficiency of an enzyme in the body called dihydropyrimidine dehydrogenase (DPD).

Not to be used in

  • People who are taking medicines known as antiviral nucleosides, such as brivudine or sorivudine, used for the treatment of shingles and chickenpox.
  • Pregnancy.
  • Breastfeeding.
  • This medicine is not recommended for children and adolescents under 18 years of age.

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine should not be used in pregnancy. Seek medical advice from your doctor.
  • This medicine should not be used by breastfeeding mothers. Discuss this with your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Increased sensitivity of the skin to light (photosensitivity - see warning section above).
  • Soreness of skin on the area where it is applied.
  • Skin reactions such as rash and itching.
  • Allergic skin reactions.
  • Severe skin rash (erythema multiforme).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while using this one, to make sure that the combination is safe.

Fluorouracil is broken down in the body by an enzyme called dihydropyrimidine dehydrogenase (DPD). The action of DPD is inhibited by medicines known as antiviral nucleosides, such as brivudine and sorivudine, this may increase the risk of side effects from fluorouracil. People who need to take brivudine and sorivudine for the treatment of shingles or chickenpox should not be stop using Efudix cream.

Other medicines containing the same active ingredient

There are currently no other topical medicines available in the UK that contain only fluorouracil.

Actikerall cream contains fluorouracil in combination with salicyclic acid and is used to treat actinic keratoses.

Fluorouracil is also available as an injection and is used in the chemotherapy treatment of breast and colon cancer.