Effective Use of Broad-spectrum Sunscreens for the Prevention of Drug-induced Photosensitivity

Abstract

In recent years, drug-induced photosensitivity as a side effect has been an increasing problem. To examine the effectiveness of broadspectrum sunscreens in preventing the disease, we quantitatively assessed efficiency of some sunscreens in suppressing the photosensitized reactions with sparfloxacin, a fluoroquinolone antibacterial agent. Some broad-spectrum sunscreens suppressed sparfloxacin-photosensitized formation of strand-breakage in plasmid pBR322 DNA. The present findings suggest that the use of broad-spectrum sunscreens contributes to the prevention of drug-induced photosensitivity. In addition, the suppressive effects showed a linear relation with the effective UV-A quanta absorbed by the tested sunscreens independent of the product types and manufacturers. Therefore, we propose that the indication of UV-A absorption spectrum in addition to PA classification (protection grade of UV-A) as factors for assessing for the ability of sunscreens to prevent drug-induced photosensitivity. An in vitro method to assess quantitatively the effectiveness of broad-spectrum sunscreens in preventing druginduced photosensitivity was also presented.