A novel 0.5% fluorouracil cream is minimally absorbed into the systemic circulation yet is as effective as 5% fluorouracil cream.

Recent in vitro and in vivo studies compared the absorption of a 0.5% fluorouracil cream with that of a 5% fluorouracil cream, following topical application to the skin. Both studies demonstrated that fluorouracil is minimally absorbed into the systemic circulation. Despite a one-tenth concentration difference between formulations, the cumulative amount of fluorouracil excreted in the urine of patients treated with the 0.5% cream was one fortieth that of patients treated with the 5% cream. Interestingly, higher percentages of fluorouracil were retained in the skin following application of the 0.5% cream compared with the 5% cream, suggesting that delivery of the 0.5% cream may be more targeted to the affected area. Other studies have demonstrated that the 0.5% cream is as effective as the 5% cream for the treatment of actinic keratoses (AKs) and has a more favorable tolerability profile. Therefore, this new 0.5% fluorouracil cream may be a safer, yet equally effective treatment alternative.