Instructions for 5-Fluorouracil (5-FU) Cream (Efudix) application

What is 5-FU?

5-FU cream is a treatment that selectively destroys abnormal cells, in your case abnormal cells in the anogenital region, whilst retaining the normal healthy skin cells.

5-FU is prescribed for the treatment of pre-cancerous lesions, in this case anogenital high-grade squamous intraepithelial lesions (HSIL). Treatment with 5-FU is considered to be “off-label.” This means that it is being prescribed for a condition or in a manner not included in the original studies used for regulatory approval, but studies have shown this to be an effective treatment for patients with HSIL.

After a course of 5-FU cream, the affected area will become inflamed. Side effects include redness, soreness, oozing, crusts and scabbing. These side effects will settle over a few weeks.

5-FU cream may cure or improve your condition, but it does not work for everybody. If this does not work, we will offer you alternative treatments such as topical trichloroacetic acid (TCA) or laser ablation.

How should I apply 5-FU?

5-FU cream can be applied with a clean fingertip. Wash the affected area and dry it before applying. Apply a thin layer of the cream to the entire treatment area.

Please see diagrams below for more detail.

You should wash your hands thoroughly after applying 5-FU cream.

How often should I use 5-FU?

Apply twice a day (morning and evening) for 5 days a week, then stop for 9 days. Repeat this 2- week cycle for 16 weeks.

How do I manage side-effects

The affected area will become inflamed. To help with these symptoms, bathe the area with water, dab the skin dry and apply petroleum jelly daily (Vaseline). Keeping stools soft, sitz baths and lidocaine 5% ointment can help.

Rarely you can have an allergic reaction. 5-FU can cause scarring, ulceration and the area can become infected.

Please let us know if:
• you are planning on getting pregnant
• you are breast feeding
• you have a known dihydropyrimidine dehydrogenase (DPD) deficiency. DPD is an enzyme made by the liver. It helps break down certain chemotherapy drugs)

Instructions for applying Efudex (5-flououracil) cream

References:
1) Brogden, Danielle RL, et al. "Evaluating the e=icacy of treatment options for anal intraepithelial neoplasia: a systematic review." International Journal of Colorectal Disease 36 (2021): 213-226.