Which term describes the movement of a drug through the body?

• A. Pharmacokinetics
• B. Pharmacodynamics
• C. Toxicology
• D. Pharmacoeconomics

Answer: (A)

Pharmacokinetics is the movement of a drug through the body, covering absorption, distribution, metabolism, and excretion. These processes determine how quickly a drug enters the bloodstream, reaches target tissues, is transformed, and is eliminated, shaping onset, duration, and intensity of effect. Understanding pharmacokinetics explains why routes of administration matter, how organ function influences drug levels, and why dosing regimens are structured the way they are. Pharmacodynamics, by contrast, describes what the drug does to the body—the mechanism of action and the relationship between dose and effect. Toxicology focuses on harmful effects and safety thresholds, while pharmacoeconomics examines cost-related aspects of drug therapy.