DNA polymorphisms have an important role in the genes encoding. A number of
cytochrome P450 (CYP) enzymes are leading to drug metabolism variation in different subjects.
CYP2C9 and CYP2C19 metabolize many clinically important drugs. Inter-individual
variability in drug metabolism may change drug reactions and variability in drug efficiency.
Cytochrome P450 (CYPs) polymorphisms may show an important effect on drug metabolism,
toxicity and hepatotoxicity. The most common clinical effects are associated with
CYP2C19 and CYP2C9 mutants. Differences in genetic polymorphism of these cytochromic
enzymes in inter-individual still remain unknown.
This review article summarizes the most important polymorphisms of 2C9 and 2C19 diversity
which is important for metabolism of some drugs and treatment of several diseases.
Determining the pharmacokinetic effects of CYP2C19 and CYP2C9 genotypes may help
physicians choose the optimal dosage of some drugs for the treatment and prevention of
their side effects. Since different ethnic groups from all over the world use medications, it
seems necessary to investigate the pharmacokinetic effects of CYP2C19 and CYP2C9 genotypes
in different populations, due to drug consumption with optimal dosage in different