Pharmacokinetics

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Pharmacokinetics (from Ancient Greek pharmakon "drug" and kinetikos "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determine the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs, pesticides, food additives, cosmetics, etc. It attempts to discover the fate of a drug from the moment that it is administered up to the point at which it is completely eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics (PD) is the study of how the drug affects the organism. Both together influence dosing, benefit, and adverse effects.

Principles of pharmacokinetics[edit | edit source]

Pharmacokinetics is divided into several areas including, but not limited to:

  • Absorption - the process of a substance entering the blood circulation.
  • Distribution - the dispersion or dissemination of substances throughout the fluids and tissues of the body.
  • Metabolism - the recognition by the organism that a foreign substance is present and the irreversible transformation of parent compounds into daughter metabolites.
  • Excretion - the removal of the substances from the body. In rare cases, some drugs irreversibly accumulate in body tissue.

The four principles of pharmacokinetics are often graphically depicted by the so-called "ADME scheme". Each principle is described by the rate of the respective process, and these rates are influenced by the physicochemical properties of the drug.

See also[edit | edit source]

References[edit | edit source]


Pharmacokinetics Resources

Contributors: Prab R. Tumpati, MD