Drug-induced photosensitivity: culprit drugs, potential mechanisms and clinical consequences

Drug-induced photosensitivity, the development of phototoxic or photoallergic reactions due to pharmaceuticals and subsequent exposure to ultraviolet or visible light, is an adverse effect of growing interest. This is illustrated by the broad spectrum of recent investigations on the topic, ranging from molecular mechanisms and culprit drugs through epidemiological as well as public health related issues to long-term photoaging and potential photocarcinogenic consequences. The present review summarizes the current state of knowledge on the topic while focusing on culprit drugs and long-term effects. In total, 393 different drugs or drug compounds are reported to have a photosensitizing potential, although the level of evidence regarding their ability to induce photosensitive reactions varies markedly among these agents. The pharmaceuticals of interest belong to a wide variety of drug classes. The epidemiological risk associated with the use of photosensitizers is difficult to assess due to under-reporting and geographical differences. However, the widespread use of photosensitizing drugs combined with the potential photocarcinogenic effects reported for several agents has major implications for health and safety and suggests a need for further research on the long-term effects.