Genotoxicity and carcinogenicity studies of antihistamines.

This review provides a compendium of the results of genotoxicity and carcinogenicity assays performed on marketed antihistamines. Of the 70 drugs examined, 29 (41.4%) have at least one genotoxicity and/or carcinogenicity test result: 12 tested positive in at least one genotoxicity assay, six in at least one carcinogenicity assay, and four gave a positive response in both at least one genotoxicity assay and at least one carcinogenicity assay. Of 19 drugs with both genotoxicity and carcinogenicity data, eight were neither genotoxic nor carcinogenic, two were carcinogenic in at least one sex of mice or rats but tested negative in genotoxicity assays, five tested positive in at least one genotoxicity assay but were non-carcinogenic, and four gave a positive response in at least one genotoxicity assay and in at least one carcinogenicity assay. Only 12 (17.1%) of the 70 drugs examined have all data required by present guidelines for testing of pharmaceuticals, but it should be considered that a large fraction of them were developed and marketed prior the present regulatory climate.