Which processes are part of pharmacokinetics?

• A. Bioavailability.
• B. Pharmacodynamics.
• C. Therapeutic effect.
• D. Absorption, distribution, metabolism, excretion.

Answer: (D)

Pharmacokinetics describes what the body does to a drug, focusing on absorption, distribution, metabolism, and excretion. These four processes—absorption into the bloodstream, distribution to tissues, metabolism (often in the liver), and excretion (via kidneys or bile)—together determine how quickly a drug acts, how much reaches its site of action, and how long it stays in the body. Bioavailability is a pharmacokinetic parameter that tells you the fraction of the dose that reaches systemic circulation, but it’s not a process itself. Pharmacodynamics focuses on the drug’s effects on the body, and the therapeutic effect is the clinical outcome, not a movement or processing step.