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Adv Drug Deliv Rev. 2003 Jan 21;55(1):53-81.

Drug-drug interaction mediated by inhibition and induction of P-glycoprotein.

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Department of Drug Metabolism, Merck Research Laboratories, WP75A-203, West Point, PA 19486, USA.


P-glycoprotein (P-gp), the most extensively studied ATP-binding cassette transporter, functions as a biological barrier by extruding toxic substances and xenobiotics out of cells. In vitro and in vivo studies have demonstrated that P-gp plays a significant role in drug absorption and disposition. Like cytochrome P450 enzymes, inhibition and induction of P-gp have been reported as the causes of drug-drug interactions. Because many prototypic inhibitors and inducers affect both CYP3A4 and P-gp, many drug interactions caused by these inhibitors and inducers involve these two systems. Clinically, it is very difficult to quantitatively differentiate P-gp-mediated drug interactions versus CYP3A4-mediated drug interactions, unless their relative contributions can be accurately estimated. Therefore, care should be exercised when interpreting drug interaction data and exploring the underlying mechanisms of drug interactions.

[Indexed for MEDLINE]

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