Fluorouracil (often called 5-FU) is an antineoplastic (anti-cancer) medication that's available in several forms. When used as a topical treatment, it's commonly prescribed to treat actinic keratosis and superficial basal cell carcinoma, which are pre-cancerous and cancerous skin growths

Fluorouracil Cream (Efudex) inhibits the synthesis of DNA of rapidly dividing cells. It is used in the treatment of superficial basal cell carcinoma where surgical resection is not possible.

Fluorouracil Cream Uses:

• Actinic or solar keratosis:
  • It is indicated for the treatment of multiple actinic or solar keratoses
• Basal cell carcinoma (5%):
  • It is indicated for the treatment of superficial basal cell carcinomas when conventional methods of treatment are not possible such as in patients with multiple lesions or those with difficult-to-treat sites.
• Limitations of use:
  • The diagnosis of superficial basal cell carcinoma should be established before treatment initiation. It has not been proven to be effective in other types of basal cell carcinomas.
  • The success rate of topical fluorouracil is close to 93% in the treatment of superficial basal cell carcinoma while the success rate of surgery in lesions that can be easily accessed is 100%. Surgical resection is therefore preferred where possible.

Fluorouracil Cream Dose in Adults

Fluorouracil Cream Dose in the treatment of Actinic or solar keratosis: 

0.5% Cream:

• Put a thin layer on the spots once a day, for up to 4 weeks.
• Only if it feels okay on your skin.

1% Cream:

• Put on the spots 2 times a day, for 2 to 6 weeks.

4% Cream:

• Put on the spots once a day, for 4 weeks.
• Only if it feels okay on your skin.

5% Cream or 2% & 5% Solution:

• Put on the spots 2 times a day, for 2 to 4 weeks.
• You might only see the full healing 1 to 2 months after using it.

Fluorouracil Cream Dose in the treatment of Superficial basal cell carcinoma:

5% Cream or 5% Solution:

• Put on the affected spots 2 times a day, for 3 to 6 weeks.
• If needed, you can keep using it for up to 10 to 12 weeks.

Fluorouracil Cream Use in Children:

Not indicated.

Pregnancy Risk Factor X

• Tests on animals haven't been done using skin-applied Fluorouracil.
• However, harmful effects were seen in animals when given the drug differently.
• There have been bad reactions in people using the skin products.
• Pregnant women shouldn't use it.
• Women who can get pregnant should use birth control while using the cream and for a month after stopping.

Use fluorouracil while breastfeeding

• We don't know if skin-applied fluorouracil gets into breast milk.
• Because it might harm a breastfeeding baby, you should decide to either stop breastfeeding or stop using the medicine.
• Consider what's more important: the treatment for the mother or breastfeeding the baby.

Dose in Kidney disease:

There are no dosage adjustments provided in the manufacturer’s labeling.

Dose in Liver disease:

There are no dosage adjustments provided in the manufacturer’s labeling.

Common Side Effects of Fluorouracil Cream:

• Dermatologic:
  • Application Site Scaling
  • Application Site Dryness
  • Stinging Of The Skin
  • Skin Erosion
• Local:
  • Application Site Erythema
  • Application Site Reaction
  • Application Site Burning
  • Application Site Pruritus
  • Application Site Edema
  • Application Site Pain

Less Common Side Effects of Fluorouracil Cream:

• Central nervous system:
  • Headache
• Dermatologic:
  • Skin irritation
• Infection:
  • Common cold
• Ophthalmic:
  • Eye irritation
    • Burning
    • Watering
    • Sensitivity
    • Stinging
    • Itching
• Respiratory:
  • Sinusitis

Contraindications to Fluorouracil Cream (Efudex):

Don't use fluorouracil if:

• You're allergic to it or any part of the cream.
• You lack the DPD enzyme in your body.
• You're pregnant or might become pregnant.

Warnings and precautions

Hypersensitivity

• Allergic reactions can happen when using fluorouracil.
• This includes itchy skin or a rash where you applied it, or even away from that spot.
• If you get very itchy skin or a rash that looks like eczema, it might mean you're allergic.
• Skin tests to check for allergies might not help in this case.
• If you show signs of an allergy, stop using it right away.

Local skin reactions

When you put fluorouracil on a spot:

• The skin turns red.
• Then, it might blister, peel, get sore, and then heal.
• These skin changes can last for weeks even after you stop using it.
• Side effects can include bruising, burning, scabs, dryness, swelling, irritation, pain, itching, scaling, scars, soreness, stinging, and open sores.
• If you have open or irritated skin, the medicine might get absorbed more.

Photosensitivity

• Using fluorouracil cream can make your skin super sensitive to sunlight, leading to severe sunburn.
• Don't stay long in the sun or near UV lights while using it.
• The reaction can be strong.

Deficiency of dihydropyrimidine hydrogenase enzyme:

• People who don't have enough of a certain enzyme, called DPD, can have severe reactions to topical fluorouracil.
• There was a case where someone without enough DPD had very bad side effects, like bleeding from the gut, painful mouth sores, stomach problems, high fever, red skin rash, and low blood cell counts, after using the cream.
• It's not clear if using a weaker cream would still cause these problems for these individuals.
• If someone shows signs of this deficiency, they should stop using the cream immediately.

Fluorouracil (topical): Drug Interaction

How to administer Fluorouracil Cream?

• Wash the problem skin area and dry it.
• Wait 10 minutes.
• Put enough cream on to cover the bad spots. Use a non-metal tool or wear gloves if possible.
  • For the 4% cream: Especially for face, ears, or scalp, spread a thin layer and gently rub it in with your fingertips.
• If you use your finger, wash your hands right away.
• Don't cover the treated skin with a tight bandage.
• Only use the cream on your skin. Don't put it in your eyes, mouth, on sensitive skin areas, or inside the body.

Mechanism of action of Fluorouracil Cream:

• This is a drug that messes with the building blocks of DNA.
• It stops cells from making a specific part of DNA, which prevents fast-growing cells from multiplying and causes them to die.

Absorption:

• When you use the 5% cream, about 6% of it goes into your body.

Time to Peak:

• For the 4% cream, the highest amount in your body is reached about 1 hour after putting it on.

International Brand Names of Fluorouracil:

• Carac
• Efudex
• Fluoroplex
• Tolak
• Acler
• Efurix
• Neoflur

Fluorouracil Brand Names in Pakistan:

Not Available in Pakistan.