Pharmacodynamics primarily focuses on what?

• A. Biochemical and physiological effects of drugs and their mechanisms of action
• B. Absorption
• C. Metabolism
• D. Excretion

Answer: (A)

Pharmacodynamics focuses on what the drug does to the body: the biochemical and physiological effects and the mechanisms by which those effects are produced. This covers how drugs interact with targets like receptors or enzymes, how those interactions translate into cellular signaling and physiological responses, and how the effect changes with different concentrations (the dose–response relationship). It explains why a drug produces its therapeutic effect and potential adverse effects based on its mechanism of action, affinity, and efficacy.

Absorption, metabolism, and excretion, on the other hand, describe pharmacokinetic processes—how the body handles the drug over time to determine concentrations at the target sites. These factors influence the magnitude and duration of effects but do not define the drug’s direct actions on bodily targets.