Reduction of UV-induced erythema in normal subjects by applying methimazole.

Since free radicals are probably involved in the induction of erythema following ultraviolet (UV) irradiation, a study was conducted to investigate the influence of a topical application of methimazole (a free radical scavenger), before and at different times up to 2 h, after exposure to UV radiation. Seven subjects took part and erythema was assessed 6 h after exposure by a quantitative reflectance technique. Erythema was reduced at the sites that received methimazole 15 min prior to exposure and, although the trend was towards a decrease in erythema at the sites where methimazole was applied after exposure, the mean differences in these cases were not significant. It is believed that methimazole may have a useful role in the reduction of erythema following UV irradiation.