A REVIEW ON GENETIC POLYMORPHISM OF CYTOCHROME P-450 2C19 AND ITS CLINICAL VALIDITY

Abstract

Enzymes responsible for the activation and metabolism of drugs and other compounds in humans show wide inter-individual variation in their protein expression or catalytic activity, resulting in unique drug metabolism phenotypes. Pharmacogenetics is the study of the linkage between an individual’s genotype and that individual’s ability to metabolize a foreign compound. Cytochrome P-450 (CYP) enzyme system is one of the most important drug metabolizing enzyme systems in humans. CYP2C19 isoenzyme metabolizes many clinically important therapeutic agents, notably proto-pump inhibitors, proguanil and benzodiazepines and is mainly found in the Caucasians, Africans, Americans and Oriental populations. Genetic polymorphism plays a vital role in determining the causes of variation in drug metabolism and studies on genetic polymorphism should be carried out by involving the correlation of phenotype- genotype data along with observations that relate them to the findings such as adverse drug reaction monitoring, drug therapy decisions like cost and duration of therapy.