2004) The structure of human microsomal cytochrome P450 3A4
determined by X-ray crystallography to 2.
Sildenafil and vardenafil both are metabolised primarily in the liver via the cytochrome P450 (CYP) pathway, mostly by CYP 3A4 and to a lesser extent by CYP 2C9, while tadalafil is metabolised almost solely by the cytochrome P450 3A4
Camptothecin attenuates cytochrome P450 3A4
induction by blocking the activation of human pregnane X receptor.
Differential inhibition of cytochrome P450 3A4
, 3A5 and 3A7 by five human immunodeficiency virus (HIV) protease inhibitors in vitro.
The 5'-hydroxymethyl metabolite of flucloxacillin, generated by cytochrome p450 3A4
, has also been shown in vitro to be directly toxic to biliary epithelium.
One possible explanation for this difference is that there is a 37% higher clearance rate of amiodarone in females than in males because of differences in cytochrome P450 3A4
activity and the percentage of body fat," the authors reported (Cancer 2013 April 8 2013 [doi.
ONMEL[TM], a potent cytochrome P450 3A4
isoenzyme system (CYP3A4) inhibitor, may increase plasma concentrations of drugs metabolized by this pathway.
There are several factors common to drugs that interact with grapefruit: they are all taken by mouth, the have low to intermediate bioavailability 6 meaning only a fraction of the drug will circulate in the bloodstream, with the rest digested 6 and all of them are broken down by an enzyme called cytochrome P450 3A4
, also known as CYP3A4.
In this particular case, busulfan is a substrate of cytochrome P450 3A4
, and therefore its pharmacokinetics will be dependent to some degree on the genetic variation in this enzyme.
Therapeutic drugs that behave as mechanism-based inhibitors of cytochrome P450 3A4
Although the precise mechanism is not known, it is related to amiodarone's inhibition of the cytochrome P450 3A4
(CYP3A4) enzyme, which also metabolizes simvastatin, a HMG-CoA reductase inhibitor, according to the FDA.
GB 2 395 718 B covering the use of the crystal structure of human cytochrome P450 3A4
granted on 19th January 2005