RLO: The Liver and Drug Metabolism


Stages of Metabolism

The liver hepatocytes contain all the necessary enzymes for the metabolism of drugs. The main enzymes involved in metabolism belong to the cytochrome P450 group. These are a large family of related enzymes housed in the smooth endoplasmic reticulum of the cell.

Metabolism is often divided into two phases of biochemical reaction - phase 1 and phase 2. Some drugs may undergo just phase 1 or just phase 2 metabolism, but more often, the drug will undergo phase 1 and then phase 2 sequentially.