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Drug Class: Commonly Known As: Category:
Antimetabolite Cancer-related

5-Fluorouracil - Side Effects, Precautions, and Contraindications

What side effects can 5-Fluorouracil cause?

Early side effects

  • Mild nausea, vomiting or appetite loss may be experienced.
    There are medications available, which may prevent or decrease these side effects. If you are given these medications, take them as directed.

Delayed side effects

  • A drop in blood cell counts may occur a few days after treatment
  • Mouth ulcers may occur within several days of treatment
  • Mild hair loss or thinning may begin several weeks after treatment
  • Diarrhea may occur
  • Skin and nail changes such as dryness, fissuring, darkening (may affect the veins as well) and nail ridging may occur
  • Hand-foot skin reactions with continuous infusion of fluorouracil may occur after 8 to 9 weeks or earlier. Symptoms may include tingling, redness, swelling, tenderness, skin thickening and peeling.

   Please seek medical attention if any of the following occurs:

  • Fever of 38°C or higher, chills or sore throat
  • Diarrhea lasting longer than 24 hours
  • Soreness in the mouth for more than 3 days
  • Unusual bleeding, bruising or black tarry stools

Before taking 5-Fluorouracil, what precautions must I follow?

  • Increased sensitivity to sunlight may occur
    Avoid prolonged exposure to sunlight. The use of a sunscreen and/or protective clothing may be helpful.
  • ​Minimise skin contact with harsh detergents or chemicals - use protective gloves.  

What food or medicine must I avoid when I take 5-Fluorouracil?

  • Updated on Friday, August 17, 2018
  • Article contributed by Department of Pharmacy National Cancer Centre Singapore

    The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth


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