Interaction of morphine, fentanyl, sufentanil, alfentanil, and loperamide with the efflux drug transporter P-glycoprotein.

BackgroundThe efflux transporter P-glycoprotein, a member of the adenosine triphosphate–binding cassette superfamily, is a major determinant of the pharmacokinetics and pharmacodynamics of the opioid loperamide, a well-recognized antidiarrheal agent. Animal studies indicate that P-glycoprotein limit