Fluorouracil belongs to the group of cancer-fighting medications known as antineoplastics, and specifically to the group of antineoplastics known as antimetabolites.

Fluorouracil interferes with genetic material (DNA and RNA), which is necessary for the growth and reproduction of cancer cells. Fluorouracil is used alone or along with other antineoplastic medications to treat many types of cancer including cancer of the bladder, colon, rectum, breast, ovary, head and neck, stomach, and pancreas.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

The recommended dose of fluorouracil varies widely according to the specific condition being treated, the response to therapy, and the other medications being used. The dose of fluorouracil is based on body size.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. Your doctor may decide on a dosage schedule different from that described here.

Fluorouracil is available as an intravenous (into the vein) injection. It is usually injected through a specially prepared site on the skin. Very careful handling of this medication is required. Fluorouracil should only be given by health care professionals familiar with the use of anticancer medications. It is always given in a hospital or similar setting with access to sterile equipment for preparation.

It is important that this medication be given exactly as recommended by your doctor. If you miss an appointment to receive fluorouracil, contact your doctor as soon as possible to reschedule your appointment.

As well as interfering with the genetic material DNA and RNA of cancer cells, fluorouracil can interfere with some of your normal cells. This can cause a number of side effects. Keep track of any side effects and report them to your doctor.

This medication is stored at room temperature and protected from light.

Each mL of sterile solution contains 50 mg of fluorouracil. Nonmedicinal ingredients: water for injection and sodium hydroxide.

Do not use this medication if you:

• are allergic to fluorouracil or any ingredients of this medication
• are in a poor nutritional state (poorly nourished)
• have a potentially serious infection
• have reduced bone marrow function (low blood counts)
• have been diagnosed with dihydropyrimidine dehydrogenase deficiency
• have taken brivudine, sorivudine, or other similar medications within the past 4 weeks

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is used in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who uses this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people using this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• dry or cracked skin
• headache
• increased sensitivity of the skin to sunlight
• increased skin pigmentation
• loss of appetite
• nausea
• redness or irritation of eyes
• skin rash and itching
• temporary hair thinning or loss (returns after treatments end)
• vomiting
• watering or tearing of eyes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• changes to fingernails or toenails
• changes to vision
• confusion or disorientation
• diarrhea
• fever
• heartburn
• severe nausea or vomiting
• signs of anemia (low red blood cells; e.g., pale skin, unusual tiredness or weakness)
• signs of bleeding (e.g., unusual bruising or bleeding, pinpoint red spots on skin, black tarry stools, bloody nose, blood in urine, coughing blood, cuts that don't stop bleeding)
• signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• sores in mouth and on lips
• trouble with balance

Stop using the medication and seek immediate medical attention if any of the following occur:

• pain or swelling at the site of injection
• signs of a serious allergic reaction (e.g., difficulty breathing, wheezing, or swelling of the face and throat)
• signs of heart problems (chest pain, abnormal heart rhythm, shortness of breath)
• signs of infection (fever or chills, sore throat, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, painful or difficult urination, or listlessness)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood clotting: This medication can reduce the number of platelet cells in the blood and increase your risk of bleeding. Platelets help the blood to clot, and a shortage could make you bleed more easily.

Tell your doctor immediately if you notice any signs that your blood is not clotting as quickly as usual (e.g., black and tarry stools, blood in the urine, easy bruising, or cuts that won't stop bleeding). Your doctor will do blood tests regularly to monitor the number of platelets in your blood.

Cardiovascular effects: Fluorouracil has been reported to cause effects on the heart and circulatory (blood vessels) system. Reports of heart attack, angina, irregular heart rhythm, and heart failure have been reported with the use of fluorouracil.

If you have heart disease or any other diseases of the heart and blood system, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Infection: In addition to killing cancer cells, this medication can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people with contagious infections.

Tell your doctor immediately if you notice signs of an infection such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Kidney function: Reduced kidney function can affect the dose of fluorouracil that a person needs. If you have kidney disease or reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: The liver helps remove fluorouracil from the body. When the liver is not working well, the risk of side effects is increased. If you have reduced liver function or liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Red blood cells: Fluorouracil may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.

Serious medical conditions, treatments, or surgery: People who have had recent major surgery, treatment with other anticancer medications that suppress bone marrow function, cancers that have spread to the bone, or high-dose radiation to the spine, ribs, or pelvis may experience more severe side effects of fluorouracil.

If you have experienced any of the above, or any other serious medical condition, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Skin sensitivity: Fluorouracil can make the skin more sensitive to sun exposure. An exaggerated sunburn reaction may occur. Avoid exposure to excessive sunlight, including sunlamps and tanning beds, and use sunblock with minimum SPF 30.

Vaccines: Before starting this medication, all your immunizations should be up to date. Live vaccines (e.g., BCG, yellow fever) are not recommended for people taking this medication. Talk to your doctor if you need any vaccinations while taking this medication.

Pregnancy: There is a possibility of birth defects if fluorouracil is being used at the time of conception, or if it is taken during pregnancy. Use effective birth control while you are being treated with this medication. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if fluorouracil passes into breast milk. Due to the potential for serious harm to the baby, women receiving fluorouracil should not breast-feed.

There may be an interaction between fluorouracil and any of the following:

• antiarrhythmics (e.g., amiodarone, disopyramide, dronedarone, quinidine, procainamide)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• baricitinb
• BCG
• cimetidine
• dapsone
• deferiprone
• denosumab
• echinacea
• fingolimod
• folic acid
• leflunomide
• leucovorin
• mesalamine
• methadone
• metronidazole
• natalizumab
• ocrelizumab
• other cancer medications (including but not limited to cytarabine, flucytosine, methotrexate, tamoxifen, temsirolimus)
• phenytoin
• pimecrolimus
• quinine
• roflumilast
• sotalol
• tacrolimus
• tetrabenazine
• tofacitinib
• vaccines
• warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.