The AAPS Journal

, Volume 8, Issue 1, pp E101–E111 | Cite as

Cytochrome P450s and other enzymes in drug metabolism and toxicity

  • F. Peter Guengerich


The cytochrome P450 (P450) enzymes are the major catalysts involved in the metabolism of drugs. bioavailability and toxicity are 2 of the most common barriers in drug development today, and P450 and the conjugation enzymes can influence these effects. The toxicity of drugs can be considered in 5 contexts: on-target toxicity, hypersensitivity and immunological reactions, off-target pharmacology, bioactivation to reactive intermediates, and idiosyncratic drug reactions. the chemistry of bioactivation is reasonably well understood, but the mechanisms underlying biological responses are not. In the article we consider what fraction of drug toxicity actually involves metabolism, and we examine how species and human interindividual variations affect pharmacokinetics and toxicity.


Cytochrome P450 drug metabolism toxicity reactive metabolites 


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Copyright information

© American Association of Pharmaceutical Scientists 2006

Authors and Affiliations

  1. 1.Department of biochemistry and Center in Molecular ToxicologyVanderbilt University School of MedicineNashville

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