What does pharmacokinetics study in relation to drugs?

Pharmacokinetics is a branch of pharmacology that specifically focuses on the processes that determine the fate of a drug within the body after administration. This includes the four key phases: absorption, distribution, metabolism, and excretion (often abbreviated as ADME).

Absorption refers to how a drug enters the bloodstream after administration. Distribution involves how the drug disperses throughout the body and reaches target tissues. Metabolism consists of the biochemical modifications made by the body to the drug, often occurring in the liver, which can activate or deactivate the drug. Finally, excretion is the process through which the drug and its metabolites are eliminated from the body, primarily through the kidneys.

Understanding pharmacokinetics is crucial in determining appropriate dosing regimens, predicting drug interactions, and assessing how the drug will perform in different populations (e.g., those with organ impairment, or in the elderly). Thus, it provides a comprehensive framework for understanding how a drug behaves within the system, which is essential for ensuring safe and effective therapeutic use.