fluorouracil/salicylic acid

Action and Spectrum

Actions and Spectrum 

fluorouracil interferes with the synthesis of DNA and RNA in cancer cells, which inhibits their growth and leads to cell death. salicylic acid works involves ability to dissolve keratin, a protein found in the outer layer of the skin. By breaking down these cells, it helps to clear pores and remove dead skin.

Drug Interaction

Adverse Reaction

Frequency defined  

>10%  

Dermatitis [<1%] 

Scaling [<1%] 

Pain [25%]  

Pruritus [45%]  

Edema [<1%]  

Erosion [7%] 

Irritation [≤86%]  

Erythema [11%] 

Burning [≤86%] 

Dermal ulcer [≤1%]  

Local inflammation [73%] 

<1% 

Increased lacrimation 

Skin erosion 

Crusted skin 

Gastroenteritis 

Pruritus 

Influenza 

Dry eye syndrome 

Eye pruritus 

1-10%  

Desquamation (2%) 

Crusted skin (3%) 

Post marketing reports 

Hypersensitivity: Hypersensitivity reaction 

Dermatologic: contact dermatitis, cicatrix of skin 

Black Box Warning

Black Box Warning 

None

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Patients with a known hypersensitivity or severe allergic reaction to fluorouracil/salicylic acid should not use the drug. 

Caution: 

• Patients with pre-existing bone marrow suppression should use fluorouracil with caution. 
• Caution should be taken when using salicylic acid on broken, irritated, or inflamed skin as it may cause further irritation. 
• fluorouracil may cause harm to a developing fetus, so it is generally not recommended during pregnancy or breastfeeding.

Pregnancy / Lactation

Pregnancy consideration: 

Pregnancy category: N/A 

Lactation: Excretion into human milk is unknown  

Pregnancy Categories:         

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.  

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women. 

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits. 

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women. 

Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology  

fluorouracil is converted to active metabolites that inhibits the enzyme thymidylate synthase, leading to reduced production of thymidine, a building block of DNA.  

salicylic acid is a keratolytic agent that works by breaking down and softening the outer layer of the skin. This may be achieved by dissolving the intercellular cement substance that binds skin cells together. 

Pharmacodynamics 

fluorouracil as an antimetabolite, particularly affecting rapidly dividing cells, including cancer cells. The drug inhibits the enzyme thymidylate synthase, which is essential for the synthesis of thymidine, a building block of DNA.  

salicylic acid helps to exfoliate and remove dead skin cells, promote the elimination of the outer layer of the skin, and clear pores.  

Pharmacokinetics 

Absorption   

When applied to the skin, fluorouracil/salicylic acid are partially absorbed through the skin and can enter the bloodstream.   

Distribution 

fluorouracil/salicylic acid both are distributed throughout the body upon absorption. 

Metabolism 

fluorouracil undergoes extensive metabolism in the liver by the enzyme dihydropyrimidine dehydrogenase.  

salicylic acid is also metabolized in the liver into by including metabolites like salicyluric acid and salicyl phenolic glucuronide. 

Elimination and excretion 

fluorouracil/salicylic acid and its metabolites are excreted in the urine. 

Adminstartion

Administration 

fluorouracil is available in topical formulations for the treatment of certain skin conditions.  

salicylic acid is also available in various topical forms, including creams, lotions, patches and gels. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: fluorouracil/salicylic acid 

Why do we use fluorouracil/salicylic acid? 

fluorouracil/salicylic acid is used as a topical treatment for actinic keratosis, which results from sun damage, involves a solution combining fluorouracil, a chemotherapy drug that eliminates abnormal cells, and salicylic acid, a keratolytic agent that softens and removes the outer skin layer. This combination of medications is particularly effective in curbing the growth of actinic keratosis, especially for hyperkeratotic lesions.