What is CYP3A metabolism?
CYP3A is one of the most important cytochrome P450 isoforms responsible for drug metabolism by humans because it is the major such enzyme in critical tissues such as the gastrointestinal tract and liver, and it is involved in the oxidative biotransformation of numerous clinically useful therapeutic agents.
What drug is metabolized by CYP3A4?
Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism; substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens.
How does genetics affect drug metabolism?
Genetic variability of drug metabolizing enzymes and drug transporters has been associated with interindividual differences in pharmacokinetics and pharmacodynamics. Such differences may result in variation in drug efficacy, safety and treatment outcomes in a number of frequently prescribed drugs3.
What is CYP3A4 gene?
CYP3A4 (Cytochrome P450 Family 3 Subfamily A Member 4) is a Protein Coding gene. Diseases associated with CYP3A4 include Vitamin D-Dependent Rickets, Type 3 and Acetaminophen Metabolism. Among its related pathways are 2-Naphthylamine and 2-Nitronaphtalene metabolism and Caffeine Pathway, Pharmacokinetics.
What are CYP3A drugs?
CYP3A inducers include the glucocorticoids, rifampin, carbamazepine, phenobarbital, and phenytoin. Among the many significant CYP3A inhibitors are grapefruit juice, erythromycin, ketoconazole, clarithromycin, and verapamil.
Which drugs are metabolized by CYP3A?
| Sensitive index substrates unless otherwise noted | |
|---|---|
| CYP2C9 | tolbutamide(c), S-warfarin(c) |
| CYP2C19 | lansoprazole (c,d), omeprazole |
| CYP2D6 | desipramine, dextromethorphan, nebivolol |
| CYP3A | midazolam, triazolam |
What is the role of CYP3A4?
CYP3A4 is a major cytochrome P450. It catalyses a broad range of substrates including xenobiotics such as clinically used drugs and endogenous compounds bile acids. Its function to detoxify bile acids could be used for treating cholestasis, which is a condition characterised by accumulation of bile acids.
What are pharmacokinetic genes?
Pharmacokinetic (PK) genes mediate transport of drugs into and out of cells and their metabolic processing. For example, PK genes can be activated within tumor tissues and thereby compromise the efficacy of an administered therapy independent of the target.
What are the factors affecting drug metabolism?
Physiological factors that can influence drug metabolism include age, individual variation (e.g., pharmacogenetics), enterohepatic circulation, nutrition, intestinal flora, or sex differences. In general, drugs are metabolized more slowly in fetal, neonatal and elderly humans and animals than in adults.
What is the CYP3A4 responsible for?
What does CYP3A stand for?
Cytochrome P450, family 3, subfamily A
Cytochrome P450, family 3, subfamily A, also known as CYP3A, is a human gene locus. A homologous locus is found in mice.
What is the difference between CYP3A4 and CYP3A?
CYP3A4 is the most abundantly expressed CYP and accounts for approximately 30 to 40% of the total CYPcontent in human adult liver and small intestine. CYP3A5 is 83% homologous to CYP3A4, is expressed at a much lower level than CYP3A4 in the liver, but is the main CYP3A isoform in the kidney.
What drugs are metabolized by CYP3A?
Up to 60% of the liver’s total cytochrome P-450 is CYP3A, and nearly 50% of all clinically relevant medications are metabolized by CYP3A. The presence of CYP3A in the small intestine results in decreased bioavailability of many ingested drugs. CYP3A inducers include the glucocorticoids, rifampin, carbamazepine, phenobarbital, and phenytoin.
How many studies are there on CYP3A substrates and drug-drug interactions?
Further literature searching was carried out to identify DDI investigations of other inducers (CBZ, PHY, and PHB) with the CYP3A substrates. A total of six studies were identified as summarized in Table 4. TABLE 4 Summary of the clinical drug-drug interactions studies available within the literature
What are CYP2B and CYP3A?
CYP3A and CYP2B are important members of the CYP family of enzymes, responsible for the metabolism of a large number of pharmaceutical drugs and herbal medicines. The two nuclear receptors that function in the metabolism of xenobiotics are CAR and PXR/SXR.
What are the substrates of CYP3A4?
Important substrates include immunosuppressants (cyclosporine A, tacrolimus), calcium channel blockers, macrolide antibiotics, HMG-CoA reductase inhibitors, and anti-HIV inhibitors. CYP3A4 thought to dominate in whites and CYP3A5 in African Americans.