When two or three drugs are sustrates of the same enzyme, adverse reactions are expected if they are used simultaneously. This information helps the physician to be aware and anticipate the adverse reactions of the drugs described aboye. The tumescent liposuction can be deadly, because of the toxicity of the lidocaine or because of its interaction with different drugs. The dosage of different drugs that are metabolized or inhibited by CYPA4 can also change the lidocaine. There is a significant variability of the patients related to the enzymatic activity of the citochrome P4S0. This makes it hard to prediet the possibility of any specific drug interaction. This artiele is focused on the importance of the enzyme CYP, its activities and the most important clinic interactions.