QUINOLONE ANTIBACTERIALS - A NEW CLASS OF PHOTOCHEMICAL CARCINOGENS

Hairless mice were exposed orally to antibiotics of the fluoroquinolon e group alone and in combination with irradiation with UVA over an ext ended period of time to determine the possible skin carcinogenicity in comparison with that with 8-methoxypsoralen, i.e. a known photochemic al skin carcinogen. Animals exposed to UVA and fleroxacin, ciprofloxac in, nalidixic acid and ofloxacin exhibited an increase in the number o f benign skin tumors when compared with animals exposed to UVA alone. Animals exposed to lomefloxacin and UVA exhibited a specific type of n eoplastic progression. In addition to benign papillomas and solar kera toses, a number of cystic squamous cell carcinomas were observed. In t he positive control group, which was given 8-methoxypsoralen and UVA, a number of papillomas and superficial squamous cell carcinomas were f ound. In animals exposed to UVA alone, only a few benign tumors were s een; in unexposed animals, no cutaneous neoplasms were observed. It is concluded that fluoroquinolones warrant further study, because they h ave potential photocarcinogenic properties. (C) 1997 Elsevier Science S.A.