What is pharmacokinetics?

• A. The study of how drugs interact with each other.
• B. The chemical composition of a drug.
• C. The cost of medications.
• D. How the body absorbs, distributes, metabolizes, and eliminates a drug.

Answer: (D)

Pharmacokinetics is how the body handles a drug as it moves through four processes: absorption, distribution, metabolism, and elimination. Absorption is how the drug enters the bloodstream after administration. Distribution describes how the drug travels through the body to reach tissues and organs. Metabolism, largely in the liver, converts the drug into forms that may be active or inactive. Elimination is the removal of the drug and its metabolites from the body, mainly via the kidneys, but also through the liver, lungs, or bowel. The combination and pace of these steps determine when the drug starts to work, how strong its effect will be, and how long it lasts. This is about the body's handling of the drug, not about interactions, the drug’s chemical makeup, or cost.