Pharmacokinetics

Pharmacokinetics (in Greek: "pharmacon" meaning drug, and "kinetikos" meaning putting in motion) is a branch of pharmacology dedicated to the determination of the fate of substances administered externally to a living organism. In practice, this discipline is applied mainly to drug substances, though in principle it concerns itself with all manner of compounds ingested or otherwise delivered externally to an organism, such as nutrients, metabolites, hormones, toxins, etc. Pharmacokinetics is often divided into several areas including, but not limited to, the extent and rate of Absorption, Distribution, Metabolism and Excretion. This sometimes is referred to as the ADME scheme.

Absorption is the process of a substance entering the body. Distribution is the dispersion or dissemination of substances throughout the fluids and tissues of the body. Metabolism is the transformation of the substances and its daughter metabolites. Excretion is the elimination of the substances from the body. In rare cases, some drugs irreversibly accumulate in a tissue in the body.

Pharmacokinetics is often studied in conjunction with pharmacodynamics. So while pharmacodynamics explores what a drug does to the body, pharmacokinetics explores what the body does to the drug.

Pharmacokinetics is sometimes abbreviated as "PK".