Which statement best defines pharmacokinetics?

• A. What the drug does to the body
• B. How the body processes the drug
• C. The ratio of absorption to dose administered
• D. The mechanism of drug action

Answer: (B)

Pharmacokinetics describes how the body processes a drug—how it is absorbed into the bloodstream, distributed to tissues, metabolized (often by the liver), and eliminated (primarily by the kidneys). This focus on the fate of the drug in the body explains concentration over time, onset and duration of effect, and how dosing changes impact those factors. The other ideas describe what the drug does to the body (pharmacodynamics), or a specific ratio related to absorption and dose, which doesn’t capture the full processes of absorption, distribution, metabolism, and excretion.