Which term refers to the therapeutic or adverse effect on the body?

• A. Interaction
• B. Pharmacology
• C. Pharmacodynamics
• D. Pharmacokinetics

Answer: (A)

The effect a drug has on the body—whether it improves a condition or causes a side effect—is described by pharmacodynamics. This area looks at how the drug interacts with its target, such as receptors, and how those interactions translate into measurable effects as the drug concentration changes. It explains why a medication might lower blood pressure at a certain dose or produce dizziness at another.

Pharmacokinetics, on the other hand, is about what the body does to the drug: how it is absorbed, distributed, metabolized, and excreted, which determines the drug’s concentration at the site of action and the duration of its effect. Pharmacology is the overarching field that encompasses both pharmacodynamics and pharmacokinetics. An interaction refers to how two or more drugs influence each other’s effects, which can modify therapeutic or adverse outcomes but isn’t the term for the body’s direct response to a single drug.