Fluorouracil is used to treat various types of cancer. It is a chemotherapy drug that is used to slow or stop cancer cell growth.

This medication is usually given by injection into a vein by a health care professional. It may also be given by other methods of injection depending upon your medical condition. The dosage is based on your medical condition, body size, and response to treatment.

Nausea, vomiting, loss of appetite, dry/itchy skin, or skin darkening may occur. Nausea and vomiting can be severe. In some cases, drug therapy may be necessary to prevent or relieve nausea and vomiting. Not eating before your treatment may help relieve vomiting. Changes in diet such as eating several small meals or limiting activity may help lessen some of these effects. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Mild diarrhea is also a common side effect. However, diarrhea can rarely become severe, causing very serious problems due to dehydration. Tell your doctor right away if you develop: diarrhea that is severe or doesn't stop, abdominal or stomach pain/cramping, or blood/mucus in your stool.

Temporary hair loss may occur. Normal hair growth should return after treatment has ended.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Hand and foot problems sometimes occur with fluorouracil use. You can prevent or reduce these problems by protecting your hands and feet from a great deal of heat or pressure. For example, avoid taking hot baths/showers, handwashing dishes with hot water, taking long walks, and rubbing your hands/feet. Tell your doctor right away if you develop the following symptoms on your hands/feet: redness, peeling skin, blisters, pain, numbness, tingling, or swelling. If you develop these symptoms, consult your doctor for treatment options (such as reducing your dose or stopping fluorouracil therapy, applying ice packs to the hands/feet).

Tell your doctor right away if you have any serious side effects, including:

• headache
• mental/mood changes (such as confusion)
• vision changes
• unusual eye movements
• loss of coordination
• unusual tiredness

Get medical help right away if you have any very serious side effects, including:

• easy bruising/bleeding
• blood in the urine
• black/bloody stools
• vomit that looks like coffee grounds
• stomach/abdominal pain
• chest pain
• jaw/left arm pain
• fast/slow/irregular heartbeat
• mouth sores
• sore throat
• painful swallowing
• heartburn
• pain/redness/swelling of the arms/legs

This medication can lower the body's ability to fight an infection. Tell your doctor right away if you develop any signs of an infection (such as sore throat that doesn't go away, fever, chills).

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

Fluorouracil can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Get medical help right away if you develop a rash.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

See also Warning section.

Before using fluorouracil, tell your doctor or pharmacist if you are allergic to it; or to flucytosine; or to capecitabine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• poor nutrition
• decreased bone marrow function/blood cell disorders (such as anemia, leukopenia, thrombocytopenia)
• a serious infection
• liver problems
• kidney problems

Tell your health care professional that you are using fluorouracil before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using fluorouracil. Fluorouracil may harm an unborn baby. Men and women using this medication should ask about reliable forms of birth control during treatment and for some time after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

A product that may interact with this drug is:

• warfarin

Fluorouracil is very similar to flucytosine and capecitabine. Do not use medications containing flucytosine or capecitabine while using fluorouracil.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as complete blood counts, genetic testing, kidney/liver function) may be done before you start using this medication and while you are using it. Keep all medical and lab appointments. Consult your doctor for more details.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).