Which term covers the mechanisms of drug action and physiological effects?

• A. Biotransformation
• B. Medication absorption
• C. Pharmacodynamics
• D. Mechanism of action

Answer: (C)

Pharmacodynamics is the study of how drugs affect the body, including the mechanisms by which drugs produce their effects and the resulting physiological changes. It covers how a drug interacts with targets like receptors or enzymes, the resulting responses, and how those responses vary with dose. While “mechanism of action” refers to the specific molecular interaction, pharmacodynamics includes that mechanism plus the broader physiological effects and dose–response relationships. In contrast, biotransformation describes metabolism, and absorption concerns how a drug enters the bloodstream—both pharmacokinetic aspects that don’t address the effects produced. So pharmacodynamics best covers both the mechanisms of action and the physiological effects.