The pharmacology dictionary, in two languages.

The rate at which a drug is removed from the body, primarily by the liver and kidneys, representing the volume of plasma cleared of the drug per unit time.

The component of total clearance due to hepatic metabolism and biliary excretion; the volume of blood cleared of drug by the liver per unit time.

The component of total clearance attributable to the kidneys: the volume of plasma cleared of drug by urinary excretion per unit time.

Pharmacokinetic behaviour in which parameters such as clearance, volume of distribution and half-life do not change with dose or time, so that plasma concentrations and AUC increase in direct proportion to dose.

The integral of the plasma drug concentration–time curve, measuring total systemic exposure to a drug over a specified interval or from zero to infinity; expressed in concentration × time units (e.g. mg·h/L).

The irreversible removal of a drug from the body, comprising its metabolism (biotransformation) to other chemical species and the excretion of unchanged drug or its metabolites.

The time required for the plasma concentration of a drug to decrease by 50% during the elimination phase, reflecting how long the drug remains active in the body.

A first-order rate constant (Ke or Kel) that quantifies the fraction of drug eliminated from the body per unit time, used to calculate half-life.

A pharmacokinetic process where the rate of drug elimination (or absorption) is proportional to the drug's concentration, leading to exponential decline over time.

The fraction of drug entering the liver in the blood that is irreversibly removed during a single pass through the organ, ranging from 0 (no extraction) to 1 (complete extraction).

An initial dose, or series of doses, larger than the maintenance dose, given to reach the target plasma concentration rapidly instead of waiting 4–5 half-lives for accumulation.

The dose given at regular intervals, or the rate of a continuous infusion, that replaces the amount of drug eliminated and keeps the concentration at the desired steady-state level.

A nonlinear pharmacokinetic model describing drug elimination that transitions from first-order at low concentrations to zero-order at high concentrations due to enzyme saturation.

The branch of pharmacology that describes what the body does to a drug: the time course of its absorption, distribution, metabolism and excretion (ADME) and the resulting concentrations in plasma and tissues.

The study of the sources and magnitude of variability in drug concentrations among individuals in a target patient population, using data pooled from many patients, often with only a few samples each.

The constant plasma drug concentration achieved when the rate of drug administration equals the rate of elimination during repeated dosing.

The proportion of the total plasma drug concentration that is not bound to plasma proteins, expressed as a fraction (0–1) or percentage; only this free drug can cross membranes and interact with receptors.

A theoretical volume that describes the extent to which a drug is distributed throughout the body tissues relative to the plasma, indicating how much the drug leaves the bloodstream to enter tissues.