Cytochrome P450 2C9, 2C8, 2C19, 2E1, and 3A Enzymes (CYP2C9, CYP2C8, CYP2C19, CYP2E1, CYP3A4)

The cytochrome P450 enzymes CYP2C9, CYP2C8, CYP2C19, CYP2E1, and CYP3A4 are endoplasmic reticulum-bound oxidoreductases predominantly expressed in the human liver and involved in the Phase I metabolism of a vast array of drugs and endogenous molecules. They function by catalyzing the oxidation of substrates, thereby increasing solubility and facilitating excretion. Collectively, these five isoforms metabolize more than 80% of all clinically used drugs susceptible to CYP-mediated transformation. Inter-individual differences in their expression and genetic polymorphisms can dramatically influence drug response, safety, and efficacy. Their function is regulated by genetics, environmental factors, disease states, and co-administered medications. Note: For structured data and clinical decision making, it is recommended to separate each CYP isoform, as each has unique substrate specificity, pharmacogenomic profile, and clinical implications.

Other names

Cytochrome P450 family 2 subfamily C member 9 (CYP2C9)family 2 subfamily C member 8 (CYP2C8)family 2 subfamily C member 19 (CYP2C19)family 2 subfamily E member 1 (CYP2E1)family 3 subfamily A (CYP3A4)Drug-metabolizing CYP enzymeshepatic P450s

Most drugs listed are substrates and are metabolized to active, inactive, or toxic metabolites. Some drugs inhibit CYP activity, leading to increased substrate concentration. Some drugs induce CYP expression, decreasing substrate concentration.