1. What Is The 5-Fluorouracil Injection Used For?

• Diverse Cancer Targets: 5-Fluorouracil (5-FU) is a versatile warrior, combating an array of malignancies.
  
  It serves as an adjuvant or palliative therapy for breast cancer, liver cancer (both primary and metastatic), pancreatic cancer, ovarian cancer, and primary bronchopulmonary adenocarcinoma.
  
  Moreover, it plays a crucial role in treating malignant hydatidiform mole and choriocarcinoma.
  
  For those with serous cavity malignant effusion and bladder cancer, it offers hope through intracavitary chemotherapy.
  
  In the case of head and neck malignancies and liver cancer, arterial intubation chemotherapy becomes a viable option.

2. What Is The Mechanism Of Action Of 5-fluorouracil?

The chemical structure of 5-Fluorouracil is integral to its function. Comprising specific carbon, nitrogen, hydrogen, and fluorine atoms arranged in a distinct configuration, it forms a pyrimidine base analogue.

This unique structure enables it to interfere with DNA and RNA synthesis within cancer cells. By mimicking natural nucleotides, it disrupts the normal replication and transcription processes.

The fluorine substitution at a particular position on the uracil ring enhances its binding affinity to key enzymes involved in nucleic acid metabolism, thus selectively targeting rapidly proliferating cancer cells.

Understanding this 5 fluorouracil mechanism of action aids in grasping its mode of action and potential therapeutic applications more comprehensively.

3. Dosage Regimens of 5-Fluorouracil Injection

• Adult Dosage: The adult dosage is meticulously calibrated.
  
  For slow intravenous infusion, a daily dose of 0.5 - 1 g is administered with a 5-day consecutive regimen every 3 - 4 weeks.
  
  Alternatively, 0.5 - 0.75 g can be given weekly for 2 - 4 weeks, followed by a 2-week hiatus to complete a treatment cycle.
  
  Remarkably, a slower infusion rate not only enhances efficacy but also mitigates toxic side effects. In arterial catheter injection, the dosage ranges from 0.75 - 1 g per session.
• Pediatric and Special Considerations: In pediatric cases, the dosage is calculated based on body weight, approximately 10 - 12 mg/kg per intravenous infusion.
  
  For the elderly, those with hepatic or renal insufficiency, and especially those with bone marrow suppression, dosage adjustment is imperative to ensure safety and effectiveness.

4. 5-fluorouracil Side Effects, Contraindications and Warnings

• Navigating Adverse Effects Of 5-fluorouracil: While 5-fluorouracil is a powerful ally, it does present certain challenges.
  
  Common adversities include nausea, anorexia, vomiting, oral mucositis or ulcers, abdominal discomfort, and diarrhoea.
  
  Additionally, leukopenia, alopecia, venous ascending pigmentation, neurological toxicity, arterial embolism or thrombosis, local infections, abscess formation, and thrombophlebitis may occur.
  
  However, with vigilant medical supervision, these can be managed.
• Contraindications and Warnings: Those with severe hypersensitivity to the drug, pregnant or lactating women, and individuals with concurrent varicella or herpes zoster must refrain from using it.
  
  Special caution is advised for patients with abnormal liver function, low blood cell counts (below 3500), thrombocytopenia (below 50000), infections, bleeding disorders, fever exceeding 38 °C, gastrointestinal obstruction, fluid imbalance, or electrolyte disturbances.
  
  Regular blood tests before and during treatment are essential for monitoring. Importantly, this drug is not suitable for intrathecal injection and should generally not be combined with radiotherapy, except in specific circumstances as a radiosensitizer.

5. Drug Interactions of 5-Fluorouracil Injection

• Synergistic and Antagonistic Effects: When used in conjunction with methotrexate, a specific sequence must be followed.
  
  Methotrexate should be administered first, with a 4 - 6 hour interval before introducing 5-Fluorouracil, as concurrent use may undermine its effectiveness.
  
  In contrast, a prior infusion of 60 - 300 mg of calcium folate can augment the efficacy of 5-Fluorouracil.

6. Storage and Shelf Life of 5-Fluorouracil Injection

• Preserving Efficacy: To maintain its potency, 5-Fluorouracil must be stored in a light-proof and tightly sealed environment. Its shelf life is 24 months, ensuring a reasonable window for medical use.

7. Patient Empowerment

For cancer patients and their families, understanding these details is crucial. Knowledge empowers you to engage in informed discussions with healthcare providers, ensuring the best possible treatment decisions.

However, DengYueMed offers this information as a guide, not a substitute for professional medical advice. Consult your doctor before any treatment.