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 ?
In part, the effects are due to a down-regulation of ABC-transporter proteins (P-gp, MRP1, and BCRP), metabolic genes (GST, CYP3A4, and PXR) and an up-regulation of caspase family genes.
We therefore set out to assess the relative contributions of CYP3A5 and CYP3A4 to the formation of the main tacrolimus metabolite (13-O-demethyltacrolimus), using cDNA-expressed enzymes and a bank of human liver microsomes derived from low and high CYP3A5 expressers.
This substance inhibits CYP3A4 and CYP1A2, and--if it is taken concurrently with clozapine or olanzapine--the drug's side effects may appear at a lower dosage.
The inhibitory effects of miltirone on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 were investigated with individual probe substrates in pooled HLMs via four reactions including phenacetin 0-deethylation, tolbutamide hydroxylation, dextromethorphan 0-demethylation and testosterone 6[beta]-hydroxylation, respectively.
In particular, the NNRTIs metabolised by CYP3A4 have shown to interact with PIs, which are inhibitors of CYP3A4, especially ritonavir, a potent inhibitor.
It is reported that xanthone derivatives from mangosteen extract inhibited the metabolism of CYP2C9 and CYP3A4 substrates in both competitive and linear-mixed inhibition manners, while the inhibition mode of CYP1A2 was linear-mixed (Foti et al.
We investigated CYP3A4 mRNA expression in 31 human blood samples from healthy volunteers (20 males and 11 females; mean age, 29 years; range, 20-64 years) and in three human liver samples obtained from the International Institute for the Advancement of Medicine (Exton, PA).
Coadministration of strong CYP3A4 inducers, such as rifampin, carbamazepine, St.
Consider the potential effects of increased plasma concentrations of midazolam or other benzodiazepines metabolized via CYP3A4 (alprazolam, triazolam) when administering with AKYNZEO.
Assurance that prescribers would be fully apprised of the serious risks of hypotension and syncope associated with the drug, exacerbation of those side effects when combined with alcohol or a CYP3A4 inhibitor--and the modest effects over placebo --was cited by several of the panelists who voted in favor of approval.
Oral contraceptives, weak CYP3A4 inhibitors, were allowed in the three studies, but other CYP3A4 inhibitors, including fluticasone and grapefruit, were among the exclusion criteria.
In humans, MA only weakly inhibited CYP3A4 activity in human liver microsomes and specific CYP3A4 isoform with [IC.