pharmacokinetics
Meaning of pharmacokinetics: This field tracks a drug's journey through the body over time, covering absorption, distribution, metabolism, and excretion, and it guides how doses and schedules are chosen.
Definition of pharmacokinetics
Pharmacokinetics is the study of how a drug moves through the body over time, commonly summarized by the processes of absorption, distribution, metabolism, and excretion. Absorption describes how a drug enters the bloodstream, distribution describes how it spreads to different tissues, metabolism describes how the body chemically alters it, usually in the liver, and excretion describes how it is eventually removed, often through the kidneys.
These processes together determine how much of a drug reaches its intended site of action, how quickly it takes effect, and how long that effect lasts, information used to guide dosing and timing of a medication.
Pharmacokinetics is distinct from pharmacodynamics, which instead describes the effect a drug has on the body once it reaches its target, and factors such as age, organ function, and other medications can alter a person's pharmacokinetics, changing how a given dose behaves.
Used in a sentence
The dosing schedule was adjusted based on the patient's altered pharmacokinetics related to reduced kidney function.
Good to know
Pharmacokinetics describes what the body does to a drug, while the related term pharmacodynamics describes what the drug does to the body, a distinction that is easy to conflate but refers to two different processes.
Word origin
Where “pharmacokinetics” comes from
Formed from Greek pharmakon, meaning drug, and kinesis, meaning movement, describing the drug's movement through the body.