Elimination kinetics

The elimination kinetics describes the change in the excretion of a substance ( drug ) in the body over time.

0 order elimination kinetics

Syn. Non-linear kinetics , dose-independent kinetics, capacity-limited kinetics, non-usual kinetics

A constant amount of an active ingredient is eliminated per unit of time . This means that the decrease in concentration over time is constant and therefore independent of the plasma concentration present at the moment. This relationship is not linear in a logarithmic representation. A classic example is the elimination of ethanol in the human body.

1st order elimination kinetics

Syn. Linear kinetics, dose-dependent kinetics, non-capacity-limited kinetics, usual kinetics

The decrease in concentration over time is not constant, but is proportional to the plasma concentration present at the moment, so it is a linear function of the plasma concentration in a logarithmic representation. Because a constant proportion of the plasma concentration is excreted per unit of time , the plasma concentration initially decreases rapidly and more and more slowly as the concentration decreases. This is described in a non-logarithmic representation with an exponential function . The decrease in concentration of most pharmaceuticals follows first-order elimination kinetics.

swell

• Klaus Aktories, Ulrich Förstermann, Franz Hofmann, Wolfgang Forth: General and special pharmacology and toxicology . Urban & Fischer bei Elsevier, November 2004, ISBN 3-437-42521-8