Fluorouracil 5% and 0.5% creams for the treatment of actinic keratosis: equivalent efficacy with a lower concentration and more convenient dosing schedule.

Several formulations and concentrations of topical fluorouracil have received US Food and Drug Administration (FDA) approval for the treatment of actinic keratosis (AK). The most commonly used are the fluorouracil 5% and 0.5% creams. In clinical trials, these formulations have demonstrated a marked ability to partially and completely eradicate AK lesions. Application site irritation, erythema, and burning are common side effects of both formulations, but comparative data suggest that the fluorouracil 0.5% cream is more cost-effective and may be safer, more tolerable, and as efficacious as fluorouracil 5% cream.