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 cancer chemotherapy                                                             


5-FU (5-fluorouracil)  


Brand name: Efudex, Carac, Fluoroplex 


Generic name: Fluorouracil topical 

Other names: 5-fluorouracil, 5-FU 

Therapeutic Class: antimetabolite  

Availability:  5-FU is available by prescription only   

Dosage form: 5-FU comes as a solution and cream to apply to the skin 

Indications: 5-FU is used to treat certain skin affections such as: 

  • basal cell cancer of the skin  
  • actinic keratosis, a skin condition that can lead to skin cancer  
  • Bowen's disease  
  • Genital warts. 

5-FU can be used to treat other medical conditions that are not mentioned in this article; talk to your doctor or pharmacist for more details on 5-FU. 

Dosage: Apply 5-FU to the affected area of your skin using a non-metal applicator or by wearing a glove. The entire affected area of the skin must be covered with the cream. The medication must be applied twice daily after washing/cleaning the diseased skin. After the application, wash your hands thoroughly with soap and water. Avoid the cream in contact with your eyes, eyelids, the corners of nostrils, mouth, easily irritated areas such as genitals. If the lesion is closed to your eyes, nose or mouth, you must carefully apply the medication to avoid penetration of the drug in these organs.   

In some people, 5-FU can cause inflammation and irritation of the skin. If this is your case and the inflammation is not too severe, do not discontinue the treatment; complete the therapy as recommended by your doctor. A treatment with 5-FU usually lasts 2 to 4 weeks.   

Your doctor will base on your weight, health, and the severity/extent of the tumor to prescribe you an appropriate dose of 5-FU. If you are taking other chemotherapy drugs, you may receive lower disease. Whatever the dosage recommended, it is important that you adhere to it.  Misusing 5-FU can reduce its healing power.  

Overdose:  since it is a tropical treatment, the risk of overdose is almost inexistent. However, 5-FU may cause irritation and/or inflammation even at normal. If irritation is such that you cannot continue the treatment, contact your health care provider before taking any decision.  

Missing dose: It is important that you use 5-FU exactly as indicated by your physician or pharmacist; in case you forgot to apply the medication, apply the missed dose as soon as you remember it; if it is almost time for the next dose, skip the missed dose and continue your regular dosing. Double dose is not recommended.  

Storage: Store 5-FU at room temperature and out of reach of children. The drug should not be kept in the light or moisture. After use, do not throw the container in the garbage. For more information on proper disposal of 5-FU, talk to your physician or pharmacist.    

Contraindication: While you are treated with 5-FU , you need to take the following precautions: 

·         avoid the treated area to prolonged sun exposure  

·         tell your doctor if you have a history of other skin problems or acne rosacea  

·         Tell your physician if you are taking prescription or nonprescription medications including aspiring, vitamins and nutritional supplements.   

  Mechanism of action (MOA):  5-FU acts by inhibiting DNA synthesis and thus slows or stops the division of cancer cells.  


Interactions : 5-FU is contraindicated or should be used with precaution in the following conditions:  


  • allergy to fluorouracil or any of its components  
  • Pregnancy 
  • Breastfeeding 
  • 5-FU can be applied to the skin of infants and children, but under the strict supervision of a physician.  

 Side effects: in some patients, 5-FU can cause skin reactions. Common 5-FU side effects include:  

·         rash 

·         soreness 

·         burning 

·         crusting 

·         redness 

·         discoloration 

·         irritation 

·          Itching.  

If the side effects above persist for days or weeks, contact your oncologist. In addition, contact your doctor immediately if you experience any of these symptoms:  

  • fever 
  • chills 
  • vomiting 
  • bloody diarrhea 
  • severe red skin rash 
  • Severe stomach pain.