Distribution describes which of the following?

• A. Transport of the drug from the bloodstream to body tissues and site of action
• B. Absorption into the bloodstream
• C. Metabolic transformation
• D. Elimination in urine

Answer: (A)

Distribution is the movement of a drug from the bloodstream into body tissues and to the site where it has its effect. After absorption, the circulating drug must reach its targets through the blood, and how quickly and how much gets to those tissues depends on blood flow, tissue permeability, and how the drug binds to proteins in the blood. This phase helps determine how fast a drug acts and how long its effects last. The other processes—absorption, metabolism, and elimination—describe different steps: absorption is entry into the bloodstream, metabolism is chemical changes the body makes to the drug, and elimination is removal from the body.