This page contains brief details about the drug , it's indication, dosage & administaration, mechanism of action, related brands with strength, warnings and common side effects.

Background and Date of Approval

Fluorouracil contains the active ingredient Fluorouracil. It belongs to a class of drugs called antimetabolites, which interfere with the genetic material (DNA and RNA) synthesis of rapidly dividing cancer cells, leading to their death. This medication is commonly used to treat breast, colorectal, stomach, esophagus, and pancreatic cancers. It can be administered in different ways, including through injection or as a cream.

Fluorouracil (5-fluorouracil or 5-FU) was first approved by the US Food and Drug Administration (FDA) in 1959 for treating colon and rectal cancer. Since then, it has been approved for treating other types of cancer, including breast, stomach, and pancreatic cancer. The drug is also approved in many other countries around the world. Over the years, many studies proved the effectiveness of fluorouracil in combination with other cancer treatments, and the drug continues to be an important chemotherapy medication for cancer patients.

Mechanism of Action of undefined

Fluorouracil work by interfering with the DNA and RNA synthesis of rapidly dividing cancer cells, leading to their death. It is an antimetabolite chemotherapy drug that mimics the structure of normal DNA and RNA building blocks. Still, its incorporation into DNA and RNA leads to errors in formation and causes damage to the DNA and RNA strands.

Uses of undefined

Fluorouracil is a chemotherapy medication commonly used to treat different types of cancer, including breast, colon, rectal, stomach, and pancreatic cancers. It works by interfering with the growth and division of cancer cells, ultimately causing them to die.

undefined Drug administaration and Dosage available

Fluorouracil is a medication typically administered under a healthcare provider's supervision, usually in a hospital or clinic setting. The method of administration can vary depending on the type of cancer and the individual patient's condition. The injection can be given in a vein (intravenous) or muscle (intramuscular) injection. If a patient misses a scheduled dose, they should contact their healthcare provider immediately to determine the next steps. Sometimes, the missed dose may be rescheduled, or a new treatment plan may be recommended. It is important to follow the healthcare provider's instructions closely and not make any changes to the treatment plan without first consulting with them. Patients should never take a double dose to make up for a missed dose, as this can increase the risk of side effects and toxicity.

Warnings, Precautions and Side Effects of undefined


Fluorouracil is a potent chemotherapy medication associated with several potential side effects, some of which can be severe or life-threatening. It can also cause damage to the heart, nervous system, and other organs in some patients, particularly at high doses or with long-term use. These can include myelosuppression (low level of blood cell counts), as well as diarrhea. In some cases this medication it results in mucositis (which is an inflammation of the mucous membranes), and cardiotoxicity, which can lead to damage to the heart. In rare cases, it can cause severe and potentially life-threatening side effects, such as chest pain, difficulty breathing, severe skin reactions, and signs of infection. Some patients may experience hand-foot syndrome, which can cause redness, swelling, and pain in the palms of the hands and soles of the feet (severe blisters, peeling, and difficulty walking or using the hands). 


When taking fluorouracil for cancer treatment, there are several precautions that patients should be aware of. First, avoiding getting pregnant or fathering a child while taking this medication is important, as it can harm a developing fetus. Women of childbearing age should use effective birth control during treatment and for some time afterward. Patients with liver or kidney disease may require lower doses or more frequent liver function monitoring during fluorouracil treatment. 
This medication can also make patients more sensitive to sunlight, so wearing protective clothing and sunscreen outdoors is important. Patients should also avoid getting waxed or using hair removal products during treatment, as it can cause skin irritation. Finally, it is important to keep all appointments with your healthcare provider and to report any new or worsening symptoms promptly. Patients should communicate openly with their healthcare provider about any concerns they have about their treatment. By following these precautions, patients can help ensure the safest and most effective treatment.

Side Effects

Side effects are unwanted symptoms caused by medicines. Even though all drugs cause side effects, not everyone gets them. Some of the most common side effects of include nausea, vomiting, diarrhea, and loss of appetite. These digestive symptoms can usually be managed with medication and dietary changes, but in some cases, they can be severe enough to require hospitalization.
Other common side effects include fatigue, weakness, and mouth sores. These symptoms can make it difficult for patients to carry out their normal activities, and they may require additional support and care from their healthcare providers. It can also cause hair loss, which can be distressing for some patients. However, hair loss is usually temporary and reversible once treatment is completed.
More serious side effects can also occur, such as low blood cell counts, which can increase the risk of infection, bleeding, or anemia. Patients may also experience nerve damage (neuropathy), which can cause tingling, numbness, or pain in the hands and feet. In rare cases, fluorouracil can cause severe allergic reactions, leading to breathing difficulties, swelling, and hives. It  can also cause skin reactions, especially when used topically to treat certain skin cancers. This reaction can cause redness, itching, burning, and peeling of the skin, lasting for several weeks.

Word Of Advice

If you have been prescribed Fluorouracil for cancer treatment, take your medication exactly as prescribed by your healthcare provider. Do not skip doses or change the dosing schedule without consulting your healthcare provider. It is also important to be aware of the potential side effects of injection, which can range from mild to severe. If you experience any new or worsening symptoms, report them to your healthcare provider immediately.

 If you are pregnant or breastfeeding, discuss the risks and benefits of medication with your healthcare provider. Additionally, patients with liver or kidney disease may require lower doses or more frequent monitoring of liver function during treatment. Finally, remember to keep all appointments with your healthcare provider, including blood tests and other monitoring tests, to evaluate the effectiveness of the treatment and detect any potential side effects. With careful monitoring and communication, your healthcare provider can help you navigate any challenges or concerns you may have during treatment.

Frequently Asked Question


  1. National Library of Medicine , Mediplus [ Revised on 2012] [ Accessed on 30 March ]
  2. US Food and Drug Administration (FDA) - Fluorouracil: [Last revised 2011], [Accessed on 30th March 2023],
  3. Goodman & Gilman's The Pharmacological Basis of Therapeutics, 13th edition, 2018, 1242-1256
  4. Pharmacology for Nurses: A Pathophysiologic Approach, 5th edition, 2020, 883-886


The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.