CYP3A4


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CYP3A4

A gene on chromosome 7q21.1 that encodes a member of the cytochrome P450 superfamily of monooxygenases, which catalyse reactions in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP3A4 localises to the endoplasmic reticulum; its expression is induced by glucocorticoids and drugs. It metabolises roughly half of the drugs in current use today—e.g., paracetamol (acetaminophen), codeine, cyclosporin A, diazepam and erythromycin—as well as steroids and carcinogens.

CYP3A4

One isoenzyme form of the cytochrome P450 system involved in the metabolism of many drugs. Drugs that alter this enzyme system can influence the metabolism of other agents taken by patients and cause unanticipated toxic effects.
References in periodicals archive ?
Some studies demonstrated reductions in drug levels of up to 50% with strong CYP3A4 and P-glycoprotein inducers.
Although the role of CYP3A4 and CYP3A5 enzyme at the tacrolimus metabolism is reported, the fraction of CYP 3A5 involvement remains unclear.
Boceprevir, telaprevir, and simeprevir inhibit CYP3A4 to varying degrees and therefore could affect psychotropic medications metabolized by this enzyme.
CYP3A4 is one of the most abundantly expressed cytochromes in human liver contributing on average up to 30% to the microsomal pool of P450 system[2].
CYP1A2, CYP3A4, and CYP2C19, which are other isomers of cytochrome P450, selectively perform hydroxylation of R-warfarin and converts it into inactive metabolites.
As stated earlier, the concomitant use of flibanserin with alcohol or a moderate or strong CYP3A4 inhibitor Can result in severe hypotension and syncope.
The risks of hypotension and syncope, and central nervous system depression also are exacerbated by moderate or strong CYP3A4 inhibitors.
Pooled human liver microsomes and specific human CYP3A4 isoform were obtained from Corning Gentest Corporation (Woburn, MA, USA) and stored at -150[degrees]C until use.
Of less relevance in fibroids, but important for women's health, a fraction of E1 and E2 can also undergo phase 1 detoxification processes via CYP1B1, CYP1A1 and CYP3A4, resulting in 4-hydroxyestrone (4OHE1) and 4-hydroxyestradiol (4OHE2) which have been identified as having potent oestrogenic3 and tumorigenic activity due to their ability to interact with DNA.
CYP3A4 and CYP3A5 are both expressed in liver and intestine, but CYP3A5 is the predominant form expressed in extrahepatic tissues [3] and may account for up to 50% of the total CYP3A activity in liver [4].
Oral alprazolam is extensively metabolized by the human hepatic CYP3A4 to form two less active metabolites, alphahydroxy alprazolam and 4-hydroxyalprazolam.