Photosensitive drug eruption induced by flutamide.

We describe a 68-year-old man who showed a photosensitive drug eruption induced by flutamide. The minimal erythema dose with ultraviolet A light was reduced to 2 J/cm2 under administration of flutamide, which recovered to over 16 J/cm2 after cessation of the medication, without changing the reactivity to ultraviolet B. The absorption spectrum of flutamide was not altered after ultraviolet A irradiation, suggesting that flutamide is photostable with regard to ultraviolet A. In addition, bovine serum albumin was not covalently photocoupled with flutamide under ultraviolet A. Thus, flutamide seems to have low potency to act as a photohapten, and it is likely that a non-photohaptenic mechanism operates in this photosensitivity or its active metabolite may work as a photosensitizer.