Cytochrome P450 family 2 subfamily C member 19 (CYP2C19) and Cytochrome P450 family 3 subfamily A member 4 (CYP3A4) (CYP2C19 and CYP3A4)

Cytochrome P450 2C19 (CYP2C19) and Cytochrome P450 3A4 (CYP3A4) are critical heme-containing enzymes primarily located in the endoplasmic reticulum of hepatocytes and enterocytes [2, 6]. They belong to the cytochrome P450 superfamily and are responsible for the Phase I metabolism of approximately 60-70% of clinically used drugs [4, 13]. CYP3A4 is the most abundant P450 enzyme in the human liver and metabolizes a vast array of substrates, including statins, immunosuppressants, and macrolide antibiotics [7, 8]. CYP2C19 is essential for the activation of prodrugs like clopidogrel and the metabolism of proton pump inhibitors and antidepressants [1, 9]. Both enzymes are major sites for drug-drug interactions, where inhibition or induction by one drug can significantly alter the plasma concentration and safety profile of co-administered medications [14, 17]. Genetic polymorphisms, particularly in CYP2C19, lead to significant inter-individual variability in drug response, necessitating pharmacogenetic testing for personalized dosing [3, 5, 10].

Other names

Cytochrome P450 family 2 subfamily C member 19Cytochrome P450 family 3 subfamily A member 4S-mephenytoin 4'-hydroxylaseNifedipine oxidaseCPCJCYP2CCYPIIC17CYPIIC19P450C2CP450IIC19CP33CP34CYP3ACYP3A3CYPIIIA3CYPIIIA4HLPNF-25P450C3P450PCN1VDDR3

These enzymes catalyze the Phase I metabolism of drugs through oxidation reactions, such as hydroxylation and dealkylation, to facilitate excretion or activate prodrugs [13, 10].