Fluorouracil is generally used in combination with other medications to treat colon cancer or rectal cancer (cancer that begins in the large intestine) that has gotten worse or spread to other parts of the body. Fluorouracil is used in combination with other medications to treat certain types of breast cancer after surgery to remove the tumor or radiation therapy. Fluorouracil is also used to treat cancer of the pancreas and stomach cancer. Fluorouracil is in a class of medications called antimetabolites. It works by slowing or stopping the growth of cancer cells in your body.

Fluorouracil injection should be given in a hospital or medical facility under the supervision of a doctor who is experienced in giving chemotherapy medications for cancer. Treatment with fluorouracil injection may cause serious side effects.

Fluorouracil injection comes as a solution (liquid) to be given intravenously (into a vein) by a doctor or nurse in a medical facility. The length of treatment depends on the types of drugs you are taking, how well your body responds to them, and the type of cancer you have.

Your doctor may need to delay your treatment or change your dose if you experience certain side effects. It is important for you to tell your doctor how you are feeling during your treatment with fluorouracil injection.

Before receiving fluorouracil,

• tell your doctor and pharmacist if you are allergic to fluorouracil or any of the ingredients in fluorouracil injection. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: certain chemotherapy medications such as bendamustine (Treanda), busulfan (Myerlan, Busulfex), carmustine (BiCNU, Gliadel Wafer), cyclophosphamide (Cytoxan), chlorambucil (Leukeran), ifosfamide (Ifex), lomustine (CeeNU), melphalan (Alkeran), procarbazine (Mutalane), or temozolomide (Temodar); medications that suppress the immune system such as azathioprine (Imuran), cyclosporine (Neoral, Sandimmune), methotrexate (Rheumatrex), sirolimus (Rapamune), and tacrolimus (Prograf). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have an infection. Your doctor may not want you to receive fluorouracil injection.
• tell your doctor if you have previously received radiation (x-ray) therapy or treatment with other chemotherapy medications or if you have or have ever had kidney or liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. You should not become pregnant or breast-feed while you are receiving fluorouracil injection. If you become pregnant while receiving fluorouracil injection, call your doctor. Fluorouracil may harm the fetus.
• plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Fluorouracil may make your skin sensitive to sunlight.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• nausea
• diarrhea
• vomiting
• fever, chills, sore throat, or other signs of an infection
• unusual bleeding or bruising
• bloody or black, tarry stools
• coughing up or vomiting blood or material that looks like coffee grounds

Unless your doctor tells you otherwise, continue your normal diet.

Fluorouracil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• loss of appetite
• nausea
• unusual tiredness or weakness
• dizziness
• headache
• hair loss
• dry and cracked skin
• vision changes
• eye that are teary or sensitive to light
• redness, pain, swelling, or burning at the site where the injection was given
• confusion

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• sores in the mouth and throat
• diarrhea
• vomiting
• swelling, pain, redness, or peeling of skin on the palms and soles of the feet
• fever, chills, sore throat, or other signs of an infection
• hives
• rash
• itching
• difficulty breathing or swallowing
• nosebleeds
• coughing up or vomiting blood or material that looks like coffee grounds
• unusual bleeding or bruising
• pink, red, or dark brown urine
• red or tarry black bowel movements
• chest pain

Fluorouracil may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Fluorouracil is also sometimes used to treat cancer of the cervix (opening of the uterus) and esophagus, head and neck cancer (including cancer of the mouth, lip, cheek, tongue, palate, throat, tonsils, and sinuses), ovarian cancer (cancer that begins in the female reproductive organs where eggs are formed), and renal cell cancer (RCC, a type of cancer that begins in the kidney). Talk to your doctor about the risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory.Your doctor will/may order certain lab tests to check your body's response to fluorouracil.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.