Pharmacogenomics and drug metabolism

Pharmacogenomics deals with the study of the variation of the DNA and RNA with the drug response. DNA polymorphisms play a vital role in the encoding of genes. Several cytochrome P450 (CYP) enzymes (e.g., CYP2D6, CYP1A2, CYP2C9, CYP2C19, and CYP3A4) are produced in the body, which has a significant influence on the metabolism of the drug in a patient when the drug is administered. For instance, two enzymes, CYP2C9 and CYP2C19, are responsible for metabolizing several crucial drugs, extremely important for clinical purposes. However, interindividual variations in drug metabolism have a huge impact and may result in a variation in drug reactions. Further, this significantly influences the efficiency and potency of drugs. This chapter provides deep insight into the effect of genetic variation in CYP enzyme metabolism and their clinical application. Further, it explains polymorphisms in the drug transporter genes.