Drug Metabolism

Living systems have developed elimination mechanisms to dispose of waste products and protect themselves from exposure to potentially harmful chemical compounds. Protective strategies to limit such exposure include the existence of biological barriers with selective permeability, chemical disposal of xenobiotics by chemical biotransformation, and physical disposal of xenobiotics (or its biotransformation products) through excretion routes. This chapter discusses the enzymatic systems involved in drug metabolism, and the strong integration of these systems with excretion mechanisms. The main factors that produce variability in drug metabolism are also reviewed.