An update on the genotoxicity and carcinogenicity of marketed pharmaceuticals with reference to in silico predictivity.

Information from the 1999 through 2008 Physicians' Desk Reference (PDR) was used to evaluate the genotoxicity of marketed drugs. Where available, data regarding the rodent carcinogenicity results were included (PDR and Gold potency database). In addition, computational predictivity of genotoxicity (DEREK, MC4PC) is included and expanded upon from two previous reviews. The present paper contains genotoxicity data on 545 marketed drugs. Excluded from analysis were most cytotoxic anti-cancer and antiviral drugs, nucleosides (all with known mechanistic genotoxicity), steroids with class-specific genotoxicity and biologicals or peptide-based drugs. Per assay type, the percentage of positive drugs was: Bacterial mutagenesis assay: 38/525 (7.1%), in vitro chromosome aberrations: 88/380 (26.1%); mouse lymphoma assays (MLA): 32/163 (19.1%), in vivo cytogenetics: 49/438 (11.1%). The relationship among positive genetic toxicity findings, rodent carcinogenicity, and in silico prediction is discussed. Finally, supporting evidence is presented for the idea that the presence of an N-dialkyl group or piperidine aryl ketone may somehow be associated with genotoxicity, perhaps through DNA intercalation and consequent DNA topoisomerase II inhibition.