Effect of rifampicin pretreatment on the oral bioavailability of domperidone in healthy human volunteers.

Background: Increased exsorption of domperidone was observed from different parts of the small intestine of the rat after pretreatment with rifampicin by the everted sac method. Based on the in vitro studies the effect of rifampicin pretreatment on the pharmacokinetics of domperidone was investigated in eight healthy male volunteers.

Methods: After an overnight fast, 20 mg domperidone was administered to the volunteers, either alone or after 6 days pretreatment with a once daily dose of 600 mg rifampicin.

P-Glycoprotein- and cytochrome P-450-mediated herbal drug interactions.

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. Drug efflux pumps such as P-gp play a functional role in determining the pharmacokinetics of drugs administered by oral and parenteral routes. Determining the activity of drug efflux transport proteins has important implications in the identification of substrates and/or inhibitors.