Drug · Topical · Antimetabolite
Topical 5-Fluorouracil
5-FU; Efudix 5%; fluorouracil cream
Topical 5-fluorouracil 5% is a thymidylate synthase inhibitor that selectively kills proliferating cells. The mainstay topical agent for actinic keratosis (field treatment), Bowen's disease and superficial BCC. Cheap, effective and accessible — but produces brisk inflammatory response that limits patient adherence.
CurrentLast reviewed 25 March 2026
Indications
- Actinic keratosis — field or lesion-directed; gold-standard topical for AK with highest clearance.
- Bowen's disease — large or multifocal lesions, lower limb where surgery is challenging.
- Superficial BCC — cure rates ~70%; counsel about lower cure than surgery.
- OTR field treatment.
Dosing & protocols
- Actinic keratosis: apply twice daily for 2–4 weeks. Stop when brisk erythema / erosion develops.
- Bowen's disease: twice daily for 4–6 weeks.
- Superficial BCC: twice daily for 6–12 weeks.
- Apply with cotton bud or fingertip to affected area; wash hands afterwards.
Counselling points
- Expect erythema, oedema, crusting, erosion — these indicate the drug is working.
- Healing takes 2–6 weeks after stopping.
- Sun protection during and after treatment.
- Avoid mucosal sites and periocular skin.
- Pregnancy: avoid (teratogenicity unclear; theoretical risk).
Adverse events
- Inflammation as above.
- Pain, pruritus.
- Photosensitivity at treated site (months after).
- Hypo- or hyperpigmentation.
- Allergic contact dermatitis (rare).
References
- Jansen MHE et al. Randomized trial of four treatment approaches for actinic keratosis. N Engl J Med; 2019.
- de Berker D, McGregor JM, Hughes BR. British Association of Dermatologists' guidelines for the care of patients with actinic keratosis 2017. Br J Dermatol. 2017;176(1):20-43.
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