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Fluorouracil

Fluorouracil is a crucial chemotherapy medication that treats several cancer types through intravenous injection, such as colorectal, oesophageal, stomach, pancreatic, breast, and cervical cancer.  Known as 5-FU, this treatment helps thousands of patients fight serious illnesses. The FDA has approved fluorouracil specifically to treat gastric adenocarcinoma, pancreatic adenocarcinoma, breast adenocarcinoma, and colorectal adenocarcinoma. This article explains what fluorouracil is, its uses, how the fluorouracil tablet works, and its dosage information.

What is Fluorouracil?

Fluorouracil is a cytotoxic chemotherapy medication from the antimetabolite drug class.  The medicine blocks DNA and RNA synthesis in cells (that divide at a faster rate), which stops cancer cells from growing and multiplying. The drug comes in different forms—cream, injection, and tablet formats for various medical uses.

Fluorouracil Uses

Doctors prescribe fluorouracil tablets to treat several types of cancer:

Doctors also use it to treat oesophageal cancer, cervical cancer, and bladder tumours. The cream version helps treat actinic keratosis (sun-damaged scaly skin patches) and superficial basal cell carcinoma.

How and When to Use Fluorouracil 

Your doctor will give you specific instructions to take fluorouracil. The right dose depends on your cancer type, body weight, and overall health. The treatment usually follows cycles with rest periods between doses that let your body recover. You should never change doses or adjust your treatment schedule without talking to your doctor.

Fluorouracil Side Effects 

Common side effects are:

Serious reactions are:

  • Severe stomach pain
  • Bloody diarrhoea
  • Fever and chills

Precautions

  • The drug can harm unborn babies, so pregnant women should not use fluorouracil. 
  • Patients with bone marrow suppression, severe infections, or liver/kidney problems need extra caution. 
  • Tell your doctor about all medications you take to avoid harmful drug interactions.
  • Use sun protection and avoid going out, as the drug might increase skin sensitivity.

How Fluorouracil Works

The medication makes its way into cancer cells and changes into 3 active substances that stop cell growth.  The first change synthesises fluorodeoxyuridine monophosphate (FdUMP) (which blocks an enzyme called thymidylate synthase). Cancer cells cannot make new DNA when this blocking occurs, which stops them from multiplying. The second change lets it mimic RNA and DNA building blocks, which creates errors in genetic material. These errors lead to cell death, affecting rapidly growing cancer cells.

Can I Take Fluorouracil with Other Medicines

The medication interacts with many medicines. You should be extra careful with:

Dosage Information

Your cancer type determines the dosage:

  • Breast cancer: 500 mg/m² or 600 mg/m² on days 1 and 8 every 28 days for six cycles
  • Colorectal cancer: 400 mg/m² followed by 2400-3000 mg/m² over 46 hours every two weeks
  • Pancreatic cancer: 400 mg/m² on day one, then 2400 mg/m² over 46 hours every two weeks
  • Gastric cancer: 200-1000 mg/m² as continuous infusion over 24 hours

Your doctor will customise these doses based on your body size, health condition, and response to treatment.

Conclusion

Fluorouracil is the cornerstone treatment in fighting multiple cancers. This powerful medication blocks enzymes that cancer cells need to grow and multiply, which stops them in their tracks. Doctors use it mainly for colorectal, breast, stomach and pancreatic cancers, but doctors also prescribe it for other conditions.

You need to pay close attention to dosage instructions when taking this medicine. Your doctor will create a treatment plan based on your cancer type, body weight, and overall health. Following their guidance exactly will help ensure the best possible outcome.

Fighting cancer takes courage, and treatments like fluorouracil give hope to many patients. Your doctor's guidance throughout your treatment journey keeps you safe and improves your chances of success. Understanding how this medication works helps you take an active role in your treatment plan and becomes a powerful tool on the road to your recovery.

FAQs

1. Is fluorouracil high risk?

Fluorouracil poses some of the most important risks. It can cause serious side effects such as low blood counts, severe diarrhoea, mouth ulcers, heart problems, and infections. Patients with dihydropyrimidine dehydrogenase (DPD) deficiency face greater risks because this enzyme breaks down more than 80% of fluorouracil.

2. How long does fluorouracil take to work?

You will start seeing results from topical fluorouracil within 7-10 days. Side effects like inflammation show that the medication works. Complete results usually appear 4-8 weeks after treatment ends.

3. What happens if I miss a dose?

If you missed a dose of fluorouracil, contact your doctor, as it follows a special dosage pattern. In the case of topical fluorouracil, apply it when you remember, but if it is time for your next dose, skip the missed one.

4. What happens if I overdose?

Overdose symptoms include excessive vomiting, diarrhoea, mouth sores, fever, and bleeding. Medical attention becomes necessary right away. Call emergency services immediately.

5. What not to take with fluorouracil?

Avoid taking fluorouracil with:

  • Live virus vaccines
  • Blood thinners like warfarin
  • Cimetidine
  • Methotrexate
  • Phenytoin

6. Who cannot take fluorouracil?

Pregnant or breastfeeding women should not take fluorouracil. The medication isn't safe for people with severe bone marrow suppression, serious infections, recent major surgery, or complete DPD deficiency.

7. When should I take fluorouracil?

Apply topical fluorouracil creams at night for once-daily use. Morning and evening applications work best for twice-daily doses.

8. How many days to take fluorouracil?

Your condition determines the treatment length:

  • Actinic keratosis: 2-4 weeks
  • Superficial basal cell carcinoma: 3-6 weeks, and sometimes 10-12 weeks
  • Bowen's disease: 3-4 weeks

9. When to stop fluorouracil?

The medication works properly at the time the treated area shows marked inflammation with erosion. This inflammatory response shows that the treatment works effectively. Your doctor's approval is required before stopping the treatment.

10. Is it safe to take fluorouracil daily?

Daily applications work substantially better than weekly use. Most treatment plans recommend applications once or twice daily.

11. What is the best time to take fluorouracil?

Nighttime applications work best for once-daily doses. Morning and evening applications suit twice-daily regimens perfectly.

12. What to avoid when taking fluorouracil?

The treatment requires you to avoid:

  • Sun exposure - fluorouracil makes your skin more sensitive
  • Applying near the eyes, nose or mouth
  • Early treatment stoppage