The effects of indomethacin on long-wave ultraviolet-induced delayed erythema.

Indomethacin, a known inhibitor of prostaglandin synthesis, administered topically as a 2.5% solution, intradermally in 10 mug doses, and orally in a dose of 150 mg/day for 2 days did not diminish the delayed erythema produced a long-wave ultraviolet light (320-400 nm). The delayed phototoxic erythema produced by 8-methoxypsoralen and subsequent exposure the long-wave ultraviolet light was similarly unaffected. By comparison, topical and intradermal indomethacin treatment produced sustained decrease in the erythemal response to ultraviolet radiation in the UVB ranges (290-320 nm).