Introduction

• Developed in 1957
• Available in 4% (Tolak) and 5% (Efudix) products
  • Tolak $63, Efudix $55

Mechanism of action

• 5-FU is converted into active metabolites within the cell:
  • Fluorodeoxyuridine monophosphate, fluorodeoxyuridine triphosphate, and fluorouridine triphosphate

Indications

• Actinic keratoses
• Squamous cell carcinoma in situ
• Superficial basal cell carcinoma

Dosing

• AK: apply daily or BD until inflammatory response (usually 3 - 4 weeks)
• SCC in situ: apply BD for at least 6 weeks.
• Trials have looked at daily vs weekly application; weekly is not as efficacious

Usage

• Do not apply near eyes or mouth
• Can apply with fingers; wash hands before and after application with soap and water

Efficacy

• AK
• SCC in situ: 69% clearance after 4 weeks BD

Side effects

• Generally well tolerated
• Pain, pruritus, erythema, irritation, erosion, crusting