Efudex Topical Cream for the Treatment of Skin Cancer

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Topical (applied to the skin only) cream is a common treatment for basal cell carcinoma, the most common type of skin cancer worldwide. If your healthcare provider has prescribed Efudex (fluorouracil), one such option, it's important that you learn more about the drug so you can ensure that you are using it both safely and effectively.

Fluorouracil is available as a generic, and also goes by the brand names Tolak, Carac, and Fluoroplex.

The Phases of Fluorouracil Effects
Verywell / Cindy Chung


Efudex is a topical cream used for the treatment of superficial basal cell carcinoma when conventional methods are impractical, such as in the case of multiple lesions or difficult treatment sites on the face or scalp. It is also used to treat actinic keratosis (also called solar keratosis), which can lead to more serious invasive squamous cell carcinoma if left untreated. 

In its more potent injectable form, fluorouracil is also used to treat breast, stomach, bowel, and esophageal cancers.

How It Works

Efudex is a chemotherapy drug (an "antimetabolite") that interferes with the formation of DNA and RNA, which are essential for cell division and growth. This inhibition results in the death of quickly growing cancerous cells, which absorb more fluorouracil than healthy cells.


The success rate of treating basal cell carcinoma with fluorouracil is approximately 90 percent to 93 percent. And unlike surgery, Efudex is not likely to leave scars or permanently discolor patches of skin.

However, isolated, easily accessible basal cell carcinomas should be treated with surgery instead, since success with such lesions is almost 100 percent when this method is used.

Efudex cream achieves success rates similar to those of Aldara (imiquimod) cream. However, a 2016 review suggests that, unlike imiquimod, Efudex is best used to treat superficial lesions only, since it can improve surface appearance while allowing tumors to continue to grow beneath the skin. Notably, the same review reports that recurrence rates drop to 6 percent when its use is preceded by curettage (light scraping of the skin).

Talk to your healthcare provider about which treatment is best for you.


For basal cell carcinoma, it is recommended that 5-percent fluorouracil cream be applied two times per day in an amount sufficient to cover the lesions for at least three to six weeks. Therapy may be required for as long as 10 to 12 weeks before the lesions disappear, however.

To apply this medicine, use a cotton-tipped applicator or wear gloves. If applied with unprotected fingertips, it is important to wash your hands well after you apply the cream. Avoid the eyes, nose, and mouth.

Side Effects

In general, the treated areas may be aesthetically unpleasing during therapy and for several weeks after its cessation.

The effect of fluorouracil occurs in four phases:

  • Early Inflammatory Phase: During the first week of application, mild inflammation occurs.
  • Inflammatory Phase: During the following weeks, redness and swelling occur with some crusting and burning.
  • Tumor Disintegration Phase: Lesions resolve as the skin exfoliates.
  • Healing Phase: Over one to two weeks, new skin grows into the treatment area.

Specific side effects that usually do not require medical attention include:

  • Red or dark-colored skin
  • Erosion (loss of the upper layer of skin)
  • Eye irritation, including burning, itching, sensitivity, stinging, or watering
  • Increased sensitivity of the skin to the sun and ultraviolet light
  • Pain and burning of the affected area
  • Dryness, scaling, or swelling of the affected area
  • Skin rash or itching of the affected area
  • Tenderness

Of course, report them to your doctor or healthcare professional if they persist or are bothersome.

Inform your healthcare provider as soon as possible if you experience these more serious side effects:

  • Abdominal pain
  • Bloody diarrhea
  • Vomiting
  • Fever
  • Chills

Safety Tip

Avoid sunlight as much as possible while using Efudex since it may increase your side effects. If exposed to the sun, wear a hat and use sunscreen.


Efudex cream should not be used by women who are pregnant, considering becoming pregnant, or nursing, since it can harm the fetus.

It also should not be used if you have a dihydropyridine dehydrogenase (DPD) enzyme deficiency, since serious side effects may result. DPD is a hereditary condition that occurs in 3 percent to 5 percent of the population and requires a special genetic test to diagnose.

In addition, tell your healthcare provider if you are undergoing radiation therapy or if you have previously had an unusual or allergic reaction to fluorouracil, chemotherapy, other medicines, foods, dyes, or preservatives.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. National Library of Medicine MedlinePlus. Fluorouracil topical. Updated May 15, 2016.

  2. U.S. Food and Drug Administration. Efudex Prescribing Information. Valeant Pharmaceuticals.

  3. Lanoue J, Goldenberg G. Basal cell carcinoma: A comprehensive review of existing and emerging nonsurgical therapiesJ Clin Aesthet Dermatol. 2016;9(5):26–36.

  4. Cleveland Clinic. Fluorouracil, 5-FU skin cream or solution.

  5. American Cancer Society. Local treatments other than surgery for basal and squamous cell skin cancers.