Cytochrome P450 enzyme CYP3A4 (CYP3A4)

Cytochrome P450 3A4 is a major monooxygenase enzyme in the cytochrome P450 superfamily, responsible for metabolizing approximately half of all clinically used drugs and many endogenous substances. It is mainly expressed in the liver and small intestine, where it oxidizes a wide variety of xenobiotics (foreign organic molecules) and endogenous compounds including steroids, bile acids, and carcinogens. CYP3A4 activity can be modulated by various drugs (inhibitors or inducers) and dietary substances, resulting in clinically relevant drug-drug interactions and safety concerns. Variability in CYP3A4 activity contributes to differences in drug bioavailability, efficacy, and toxicity among patients. Monitoring and management of CYP3A4-interacting drugs are critical in clinical pharmacology

Other names

Cytochrome P450 3A4CYP3A4P450 3A4CYP3A subfamily enzyme 4

Enzyme inhibition (co-administered inhibitors block CYP3A4 activity, increasing exposure/toxicity of substrates). Enzyme induction (co-administered inducers increase CYP3A4 activity, decreasing substrate exposure/effectiveness). Altered drug metabolism (affects pharmacokinetics, e.g., absorption, systemic exposure, bioavailability).