CYP 3A

a cytochrome P450 isoform found in the gastrointestinal tract as well as hepatic and other cells; substrates include benzodiazepines, calcium channel blockers, antihistamines, steroid hormones, and protease inhibitors. Inhibited by antidepressants, azole antifungals, cimetidine, grapefruit juice, and erythromycin. Induced by phenobarbital, phenytoin, rifampin, and carbamazepine.

Farlex Partner Medical Dictionary © Farlex 2012

CYP 3A

Abbreviation for a cytochrome P450 isoform found in the gastrointestinal tract as well as hepatic and other cells; substrates include benzodiazepines, calcium channel blockers, antihistamines, steroid hormones, and protease inhibitors. Inhibited by antidepressants, azole antifungals, cimetidine, and erythromycin. Induced by phenobarbital, phenytoin, rifampin, and carbamazepine.

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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Most of CYP 3A substrates are also recognized as substrates or inhibitors of P-glycoprotein (P-gp) because of the strong overlapping substrate specificities and inhibitors between CYP 3A and P-gp.

Ritonavir and indinavir are protease inhibitors which are substrates and inhibitors of CYP 3A enzymes.

The Role of Cytochrome P450 3A5 Enzyme on the Metabolism of Tacrolimus in Rats

Pharmacokinetics of the CYP 3A substrate simvastatin following administration of delayed versus immediate release oral dosage forms.

Formulation for delivery: new concepts in colonic drug targeting

This finding and other early investigations suggested that CYP 3A had a role in risperidone metabolism, (23), (24) but these early studies and case series often involved molecules that had activity at both 3A4 and PGP.

Loss of enzyme induction: ups and downs of a hidden drug-drug interaction: patients on antipsychotics are at risk for adverse events when an inducer is removed

The members of CYP 3A are mainly found in the liver, intestine and peripheral blood cells (Shimada et al., 1994; Cholerton et al., 1992).

Reversible and irreversible inhibition of CYP 3A enzymes by tamoxifen and metabolites.