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Brand names:


Other names:

5-Fluorouracil, 5-Fluracil, 5-FU

Often used for:

Hepatoblastoma, Colorectal cancer

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What is Fluorouracil?

Fluorouracil is a type of chemotherapy. It works by slowing or stopping the growth of cells. Depending on the type of cancer, the doctor may also prescribe leucovorin to help with the anticancer effects of fluorouracil.

Patients will have regular blood draws to check blood counts and monitor liver and kidney function.

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May be given as a liquid into a vein by IV

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Possible Side Effects

  • Low blood counts (may cause increased risk of infection, bleeding, anemia and/or fatigue)
  • Nausea or vomiting
  • Loss of appetite
  • Diarrhea
  • Mouth sores
  • Changes in taste 
  • Darkening of skin color
  • Changes in nails
  • Hand-foot syndrome (tingling of the hands and feet, redness and flaking of the skin)
  • Skin irritation at the IV site
  • Stomach ulcers or bleeding
  • Hair loss
  • Headache
  • Skin irritation, rash, dry skin
  • Increased sensitivity to sun
  • Watery eyes, sensitivity to light, changes in vision
  • Infertility (may be temporary)
  • Liver problems
  • Heart problems

Symptoms of an allergic reaction may include: hives, rash, itching, difficulty breathing and/or swallowing, low blood pressure

Not all patients who take fluorouracil will experience these side effects. Common side effects are in bold, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

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Tips for Families

Be sure to discuss these and other recommendations with your doctor or pharmacist.

  • Patients should protect their skin from the sun while taking this medicine.
  • Wearing sunglasses may help with sensitivity to light.
  • If fluorouracil is given after radiation therapy, the skin area that was exposed to radiation therapy may become red again.
  • Sexually active patients should take steps to prevent pregnancy during treatment and for 3 months after completion of therapy.
  • Patients should tell their doctor if they are pregnant or breastfeeding.
  • Caregivers should follow instructions to avoid contact with patient body fluids, which can contain the drug for 48 hours after it is given.