What is the primary site of drug metabolism in the body?

The liver is known as the primary site of drug metabolism in the body due to its unique vascular and biochemical capabilities. Hepatocytes, the main functional cells in the liver, contain a variety of enzymes that facilitate the biotransformation of drugs and other substances. This process can convert lipid-soluble compounds into more water-soluble forms, which are easier for the body to excrete through urine or bile. The liver's extensive blood supply from both the hepatic artery and the portal vein allows it to efficiently process substances absorbed from the gastrointestinal tract, making it the central hub for drug metabolism.

Additionally, the liver plays a crucial role in various metabolic pathways, including phase I (functionalization reactions) and phase II (conjugation reactions) reactions, further enhancing its ability to metabolize different compounds. This specialization is critical for detoxifying substances and regulating the pharmacological effects of medications, thereby making the liver the key organ in the metabolism of drugs in the body.