Patient Handouts : Topical 5-FU (Efudex, Carac, etc.)

Topical 5-FU (Efudex, Carac, etc.)

Topical 5-FU is a cream that is used to treat precancerous skin lesions (actinic keratoses) and certain skin cancers. Actinic keratoses are precancerous growths that have the capacity to develop into squamous cell carcinoma, a type of skin cancer. Actinic keratoses can be treated in several ways, but they are most commonly treated with either liquid nitrogen (frozen) or topical medications: 5-FU or, sometimes, an unrelated medication called imiquimod.

  • Topical 5-FU cream is generally used once or twice daily. Use this medication sparingly; you do not need to use a lot of it.
  • You can apply the medication with your bare hands, but wash your hands after using it. Try to keep the medication away from your eyes.
  • Generally, after a week or two of application your skin will start to look red; this is expected. As the cream destroys the precancers or skin cancers they will become red, inflamed, irritated and slightly sore. Sometimes, itching may also develop. If your symptoms are severe, call and let us know.
  • The medication is used from 2 weeks to 6 weeks depending on what is being treated. For treatment of precancers (actinic keratoses), if your skin is very irritated and the symptoms are really bothering you then you can stop after two weeks. However, if it is not bothering you too much you should try to treat for a full 4 weeks. For treatment of skin cancers the medication is generally used for the full 6 weeks.
  • If you have never used the medication before, it is preferable to schedule an appointment about 3 weeks into your treatment so we can see if you are responding as expected.
  • If you have any questions during the treatment, call us or make an appointment to come in.
  • Avoid prolonged sun exposure while you are using this cream. If you do go out in the sun, use a broad spectrum sunscreen.
  • Very rarely the medication can cause systemic symptoms such as nausea or fatigue.
  • Once you finish the medication, the area of skin treated will be red and raw. It generally takes about 3-4 weeks for all of the inflammation to resolve. You may use Vaseline or Eucerin cream to soothe the skin. Alternatively, we can give you a prescription cream to help things heal a little faster if you would like.
  • Once your skin completely heals from the treatment, your skin should be smoother and many of the red spots should be gone.
  • Keep in mind that the reason you are going through all of this is to destroy precancers and early skin cancers to hopefully reduce your risk of larger and more serious skin cancers that may require surgery.
  • This medicine is extremely toxic to dogs and cats. Less than a gram can kill a small dog. DO NOT leave the tube where your dog or cat could get it.