Hepatic clearance

Hepatic clearance (Cl_H) is the irreversible removal of a drug either through drug metabolism in the liver (the most important mechanism), or through secretion of a drug in the bile so that it appears in the faeces. Hepatic clearance is the product of hepatic blood flow (Q_H; relatively constant in most people, at around 90 litres/hour) and the hepatic extraction ratio (E_H). So CL_H = Q_H x E_H. Thus, the major determinant of variations in hepatic clearance between drugs or between individual patients is the hepatic extraction ratio.

Click here to watch a short vodcast demonstrating the possible fates of a drug passing through the liver.