Overview: Evaluation of metabolism-based drug toxicity in drug development.

Drug metabolism can be a key determinant of drug toxicity. A nontoxic parent drug may be biotransformed by drug metabolizing enzymes to toxic metabolites (metabolic activation). Conversely, a toxic drug may be biotransformed to nontoxic metabolites (detoxification). The approaches to evaluate metabolism-based drug toxicity include the identification of toxic metabolites and the evaluation of toxicity in metabolically competent and metabolically compromised systems. A clear understanding of the role of drug metabolism in toxicity can aid the identification of risk factors that may potentiate drug toxicity, and may provide key information for the development of safe drugs.