Résumé
Pharmacokinetics (PK) describes a drug’s journey through the body, that is its absorption, distribution, metabolism and excretion over time. Pharmacodynamics (PD) is the physiological effect of a drug on the body. The relationship between the two can be used to predict how a drug will behave in a given patient. The complex, dynamic changes that affect PK and PD in the critically ill present significant challenges in treatment optimisation, especially with drugs that lack measurable parameters to determine dosing. As a patient deteriorates or improves clinically, drug regimens require regular adjustment to maximise benefit whilst minimising adverse toxic effects.