Topical 5-FU: Understanding Side Effects & Uses

Topical 5-FU, or fluorouracil, is available in concentrations of 0.5, 1 and 5 percent. It is used to treat skin lesions such as actinic or solar keratoses and some forms of superficial basal cell carcinomas. The cream is applied directly to the lesions and is typically used up to four weeks. Topical 5-FU may be used for up to 12 weeks to treat basal cell carcinoma.

Significance

• Topical 5-FU is an anti-cancer substance that has a direct effect on cells. The cream must be applied with care to prevent adverse effects to healthy skin.

Effects

• Redness, swelling and tenderness are common side effects associated with topical 5-FU and generally occur within the first week of use. There may also be blistering, ulceration, itching, darkening and drying of the skin at the site of treatment with continued use.

Treatment

• Antihistamines and over-the-counter pain medications may be recommended by the physician to treat redness, swelling and tenderness.

Warning

• Topical 5-FU can cause inflammation and ulceration if it comes in contact with the eyes, nostrils or the inside of the mouth. Thorough hand washing should follow the application to prevent inadvertently applying the cream to any of these sites.

Considerations

• Using sunscreen and shading or covering the treatment sites with hats and long sleeves when outside will help to prevent worsening side effects.