Pharmacokinetics is the study of what four processes?

• A. Absorption, distribution, metabolism, excretion
• B. Absorption, distribution, production, excretion
• C. Absorption, distribution, parasite, excretion
• D. Absorption, maturation, metabolism, excretion

Answer: (A)

Pharmacokinetics describes how the body handles a drug through four stages: absorption, distribution, metabolism, and excretion. Absorption is how the drug enters the bloodstream after administration; distribution is the movement of the drug to tissues and organs; metabolism is the chemical change the body makes to the drug (mostly in the liver); excretion is how the drug and its metabolites are eliminated from the body (primarily by the kidneys). These steps together determine the drug’s concentration in the blood over time and its ultimate effect. The other options mix in processes that aren’t part of drug handling by the body, such as production, maturation, or parasite.