Photosensitizing medications and photocarcinogenesis.

Photosensitivity is an exaggerated or abnormal response to ultraviolet (UV) or visible light exposure. Many current medications are known photosensitizers; however, the effects of the sensitization can be subclinical and go unnoticed by the person affected. While some of these drugs are used for short and defined periods, others are used indefinitely for the treatment of chronic disease. The question of whether either of these practices translates into an increased risk of skin cancer is an important one. Numerous medications have real, distinct and well-elucidated mechanisms that potentiate the development of skin cancer, while with some medications the mechanism for the observed carcinogenesis remains unclear. In this article we will discuss the clinical, mechanistic and epidemiological evidence supporting photochemical genotoxicity and carcinogenesis.