5-Fluorouracil (Generic Name)

Other Names: 5-FU, Adrucil®, Efudex®

About This Drug

5-fluorouracil is used to treat cancer. This drug is given intravenously (IV), orally, or on the skin.

Possible Side Effects (More Common)

  • Bone marrow depression. This is a decrease in the number of white blood cells, red blood cells, and platelets. Bone marrow depression usually occurs seven to 14 days after the drug is given and may increase your risk of infection, fatigue, and bleeding.
  • Soreness of the mouth and throat. You may have red areas, white patches, or sores that are painful.
  • Diarrhea that may last for several days
  • Nausea and vomiting. When these symptoms occur, they are usually mild. These symptoms begin within three to six hours after you receive the drug and may last up to 24 hours.
  • Hair loss or thinning. Usually hair loss is temporary; your hair should grow back when treatment is completed.
  • Darkening of the veins in which the 5-fluorouracil has been given by IV
  • Darkening of skin. This is usually temporary and will fade when the drug treatment is completed.
  • Pain, tingling or redness on the skin, especially on the palms of the hand and soles of the feet.
  • Sensitivity to light (photosensitivity). Photosensitivity means that you may become more sensitive to the effects of the sun, sun lamps, and tanning beds. Your eyes may water more, especially in bright light.
  • Decreased appetite

Possible Side Effects (Less Common)

  • Raised, red rash on your arms, legs, back, or chest
  • Darkening or partial loss of fingernail and toenail beds
  • Dry, itchy, or red eyes
  • Lung tissue changes.  Your doctor will monitor your lung function as needed.
  • Damage to the heart is rare. Your doctor will monitor your heart function as needed.

Sexual Problems and Reproductive Concerns

  • In men and women both, this drug may temporarily or permanently affect your ability to have children. This cannot be determined before your therapy. In men, this drug may interfere with your ability to make sperm, but it should not change your ability to have sexual relations. In women, menstrual bleeding may become irregular or stop while you are taking this drug. Do not assume that you cannot become pregnant if you do not have a menstrual period. Women may experience signs of menopause like vaginal dryness or itching.
    • Pregnancy warning: This drug may have harmful effects on the unborn child, so effective methods of birth control should be used during your cancer treatment.
    • Speak with your doctor or nurse if you plan to have children.  Ask for information on sperm or egg banking.
    • Genetic counseling is available to you to discuss the effect of this drug therapy on future pregnancies. In addition, a genetic counselor can review the potential risks of problems in the fetus due to this medication if an exposure during pregnancy has occurred.  
    • Breast feeding warning:  It is not known if this drug passes into breast milk. For this reason, women are advised to discuss with their doctor the risks and benefits of breast feeding during treatment with this drug because this drug may enter the breast milk and seriously harm a breast feeding infant.
    • Vaginal lubricants can be used to lessen vaginal dryness, itching, and pain during sexual relations.

Treating Side Effects

  • Drink 6-8 cups of fluids every day unless your doctor has told you to restrict your fluid intake due to another medical condition. A cup is 8 ounces of fluid. If you vomit or have diarrhea, you should drink more fluids so that you do not become dehydrated.
  • Mouth care is very important. Your mouth care should consist of regular, gentle cleaning of your teeth or dentures and rinsing your mouth with a mixture of 1/2 teaspoon of salt in 8 ounces of water or 1/2 teaspoon of sodium bicarbonate (baking soda) in 8 ounces of water. This should be done at least after every meal and at bedtime.
  • Avoid mouthwash that contains alcohol. Avoid alcohol and smoking because they can irritate your mouth and throat.
  • Do not put anything on your rash unless your doctor or nurse says you may. Keep the area around the rash clean and dry.
  • Speak with your nurse about obtaining a wig before you lose your hair.  Also, call the American Cancer Society at 800-ACS-2345 to find out information about the “Look Good...Feel Better” program close to where you live. It is a free program where women undergoing chemotherapy learn about wigs, turbans and scarves as well as makeup techniques and  skin and nail care.
  • Ask your doctor or nurse about medication that is available to help prevent or lessen nausea or vomiting.
  • Use sunscreen with SPF 30 or higher when you are outdoors even for a short time.
  • Cover up when you are out in the sun. Wear wide-brimmed hats, long-sleeved shirts, and pants. Keep your neck, chest, and back covered.

Food and Drug Interactions

There are no known interactions of 5-fluorouracil with food. This drug may interact with other medication. Tell your doctor and pharmacist about all the medication and dietary supplements (vitamins, minerals, herbs and others) that you are currently taking. The safety and effectiveness of dietary supplements and alternative diets are often unknown. Using these might unexpectedly affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's advice.

When to Call the Doctor

Call your doctor or nurse immediately if you have any of the following symptoms:

  • Fever of 100.5 F (38 C) or above
  • Chills
  • Shortness of breath
  • Rapid or irregular heartbeat
  • Unusual bleeding or bruising
  • Changes in vision
  • Diarrhea of three stools in a day or diarrhea with weakness or lightheadedness
  • Uncontrolled nausea that prevents you from eating or drinking
  • Vomiting more than twice in one day

Call your doctor or nurse as soon as possible if you have any of the following symptoms:

  • Difficulty walking or changes in the way you walk
  • Persistent headache
  • Painful mouth or throat that makes it difficult to eat or drink
  • Painful, red, or swollen areas on your hands or feet.

Revised January 2011

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