The phototoxic effects of benoxaprofen and their management and prevention.

During clinical trials with benoxaprofen, some patients noted burning and stinging in the skin when exposed to light and some developed onycholysis. A four-part prospective study was undertaken. During the first part of the study it was demonstrated that (1) benoxaprofen is associated with a hypersensitivity to long wave-length ultraviolet light (UVA). During the remaining three parts of the study, patients were exposed to very high doses of UVA light in order to try to induce a photosensitivity response. These studies demonstrated that (2) the symptoms of burning and stinging in the skin and signs of erythema and induration after very high-dose UVA exposure (30 Joule) may be prevented by the prophylactic application of a factor 15 sunscreen; (3) exposure to sunlight is required for the development of onycholysis in patients on benoxaprofen; and (4) the development of onycholysis was prevented by the regular use of a nail polish containing sunscreen. A commercially available, colored, opaque nail polish also would be expected to provide protection from onycholysis.