Efudex Cream for the Treatment of Skin Cancer

Patient's Guide to the Use and Side Effects of Topical Fluorouracil

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Woman Applying Skin Cream
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A common treatment for basal cell carcinoma, the most common type of skin cancer worldwide, is a topical (applied to skin only) cream, such as Efudex (fluorouracil). If your doctor has prescribed Efudex, this introduction will arm you with the information you need to use it effectively and safely.

Note that this information may not cover all possible precautions, interactions or adverse effects for this drug. If you have any questions about any drug you are taking, be sure to check with your healthcare professional.


Efudex (other brand names include Carac and Fluoroplex) 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. 

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


The success rate of treating basal cell carcinoma with fluorouracil is approximately 93 percent, based on a study of 113 lesions in 54 patients. However, isolated, easily accessible basal cell carcinomas should be treated with surgery since success with such lesions is almost 100 percent. Unlike surgery, Efudex is not likely to leave scars or permanently discolor patches of skin.

Other studies are now looking at how effective Efudex cream is on non-facial regions of the body, and how fluorouracil compares with imiquimod (Aldara) cream and cryosurgery. For example, in one German study of patients with actinic keratosis, imiquimod treatment resulted in the better clearing of the lesions and better cosmetic outcomes compared with cryosurgery and fluorouracil. Talk to your doctor 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 3 to 6 weeks. Therapy may be required for as long as 10 to 12 weeks before the lesions disappear, however. To apply for this medicine, use a cotton-tipped applicator, or use gloves if applying it with your fingertips. If applied with unprotected fingertips, it is important to wash your hands well after you apply for this medicine. Avoid applying to the eyes, nose, or mouth.

Side Effects

In general, the treated areas may be unsightly during therapy, and usually for several weeks following cessation of therapy. 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 1 to 2 weeks, new skin grows into the treatment area.

Specific side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome) 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 sun and ultraviolet light
  • Pain and burning of the affected area
  • Dryness, scaling or swelling of the affected area
  • Skin rash, itching of the affected area
  • Tenderness

More serious side effects that you should report to your doctor or healthcare professional as soon as possible include:

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

Cautions and Interactions

The 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 doctor if you:

  • Are undergoing radiation therapy
  • Have previously had an unusual or allergic reaction to fluorouracil, other chemotherapy, other medicines, foods, dyes, or preservatives

Avoid sunlight as much as possible while using Efudex since it may increase your side effects. If exposed to sunlight, wear a hat and use sunscreen. As always, also avoid tanning booths, which have been clearly linked to squamous cell carcinoma and melanoma.

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    Article Sources
    • "Carac Prescribing Information." sanofi- aventis U.S. LLC.
    • "Efudex Prescribing Information." Valeant Pharmaceuticals.
    • Krawtchenko N, Roewert-Huber J, Ulrich M, Mann I, Sterry W, Stockfleth E. "A randomized study of topical 5% imiquimod vs. topical 5-fluorouracil vs. cryosurgery in immunocompetent patients with actinic keratoses: a comparison of clinical and histological outcomes including 1-year follow-up." Br J Dermatol. 157 Suppl 2:34-40.
    • Newman MD, Weinberg JM. Topical therapy in the treatment of actinic keratosis and basal cell carcinoma. Cutis. 79(4 Suppl):18-28.