It has been said that we now live in a new era of "personalized medicine," "individualized medicine," or "precision medicine." As genetic testing becomes ubiquitous and more genetic risk and therapeutic response markers are discovered, we move closer to realizing the personalized medicine approach. Personalized medicine tests a patient's genotype (or a tumor's genotype) to customize the patient's clinical care. Pharmacogenomics (PGx) has begun to play a role in advancing personalized medicine. PGx studies how individual variations in the human genome affect medication responses.
The term "pharmacogenetics" has also been used as a synonym for PGx.
The primary reason that individuals respond to drugs differently is because there are often changes within the genes of receptor proteins and in the enzymes that metabolize drugs. These changes can affect the pharmacokinetics and pharmacodynamics of drugs. Such mutations (or polymorphisms) contribute to the differences we see between patients and the efficacy or toxicity of a given drug. In PGx, these mutations are referred to as variants. PGx offers the ability to test patients for genetic variants that can, or will, affect the disposition of drugs in the body.
