5-fluorouracil
Trade Names:
5-FU, Adrucil, Efudex (topical), Fluorouracil
Type of Drug:
5-fluorouracil belongs to the general group of chemotherapy drugs known as antimetabolites. It is used to treat several types of cancer including colon and head and neck cancers.

How Drug Works:
5-fluorouracil prevents cells from making DNA and RNA by interfering with the synthesis of nucleic acids, thus disrupting the growth of cancer cells.
How Drug Is Given:
5-fluorouracil is given as a shot in the vein (intravenously) over 5 to 10 minutes, over 20 to 60 minutes, or as a continuous infusion over 22 to 24 hours for 1 to 4 days, or longer. The treatment can be repeated weekly, every other week, or every 3 weeks, depending on the treatment regimen. 5-fluorouracil is usually given after a special vitamin, called leucovorin, which increases the effect of the 5-fluorouracil on the cancer cells. The dose depends upon your size. The dose may need to be decreased if you have problems taking the drug (severe diarrhea, or low white blood cell or platelet count).
Read the following information. If you do not understand it or if any of it causes you special concern, check with your doctor.

Before taking this drug, tell your doctor:

  • If you are trying to become pregnant, are pregnant, or breastfeeding. This drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Men and women who are taking this drug need to use some kind of birth control. However, do not use oral contraceptives (“the pill”) without checking with your doctor.

  • If you think you may want to have children in the future. Many chemotherapy drugs can cause sterility.

  • If you have any of the following medical problems: chickenpox or exposure to chickenpox, gout, heart disease, congestive heart failure, shingles, kidney stones, liver disease, or other forms of cancer.

  • If you are taking any other prescription or over-the-counter drugs, including vitamins and herbals.
Should I avoid any other medicines, foods, alcohol, and/or activities?
Your prescription and nonprescription medicines may interact with other drugs, causing harm. Certain foods or alcohol can also interact with drug products. Never begin taking a new medicine—prescription or nonprescription—without asking your doctor or nurse if it will interact with alcohol, food, or other medicines. Some drug products can cause drowsiness and affect activities such as driving.
Precautions:
While you are being treated with 5-fluorouracil, and after you stop treatment, do not have any immunizations (vaccinations) without your doctor’s okay. Try to avoid contact with people who have recently taken the oral polio vaccine. Check with your doctor about this.
5-fluorouracil can lower your blood counts (white blood cells, red blood cells, platelets). Your doctor will check your blood counts before and after each treatment to see how it affects your blood counts. Your doctor or nurse will give you specific instructions if your blood counts are low.
5-fluorouracil can decrease your white blood cell count, especially 10 to 14 days after the drug is given. This can increase your chance of getting an infection. Report fever of 100.5°F or higher, or signs of infection such as pain in passing your urine, coughing and bringing up sputum.
5-fluorouracil can cause a decrease in the platelet count. This can increase your risk of bleeding. DO NOT take any aspirin or aspirin-containing medicines. Report unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.
Tell all the doctors, dentists, and pharmacists you visit that you are taking this drug.
  • Most of the following side effects probably will not occur.
  • Your doctor or nurse will want to discuss specific care instructions with you.
  • They can help you understand these side effects and help you deal with them.
Side Effects:
More Common Side Effects
  • Decreased white blood cell count with increased risk of infection
  • Decreased platelet count with increased risk of bleeding
  • Darkening of skin and nail beds
  • Nausea
  • Vomiting
  • Sores in mouth or on lips
  • Thinning hair
  • Diarrhea
  • Brittle nails
  • Increased sensitivity to sun
  • Dry, flaky skin
Less Common Side Effects
  • Darkening and hardening of vein used for giving the drug
  • Decreased appetite
  • Headache
  • Weakness
  • Muscle aches
Rare Side Effects
  • Difficulty walking
  • Irritation of eyes
  • Increased tearing of eyes
  • Blurred vision
Other side effects not listed above can also occur in some patients. Tell your doctor or nurse if you develop any problems.
FDA Approval: This drug is approved for cancer treatment.