Drug metabolism
（重定向自Xenobiotic metabolism）
![Cytochrome P450 oxidases are important enzymes in xenobiotic metabolism.](/Images/godic/202502/21/CYP2C9_1OG25859.png")
![Phases I and II of the metabolism of a lipophilic xenobiotic.](/Images/godic/202502/21/Xenobiotic_metabolism5859.png")
Drug metabolism also known as xenobiotic metabolism is the biochemical modification of pharmaceutical substances or xenobiotics respectively by living organisms, usually through specialized enzymatic systems. Drug metabolism often converts lipophilic chemical compounds into more readily excreted hydrophilic products. The rate of metabolism determines the duration and intensity of a drug's pharmacological action.