Clearance is balanced against which process as subsequent doses are introduced?

Clearance is balanced against which process as subsequent doses are introduced?

• A. Distribution
• B. Metabolism
• C. Excretion
• D. Absorption

Answer: (D)

Absorption. In multiple dosing, steady-state is reached when the rate at which drug enters the body from each dose matches the rate at which it is eliminated. Clearance defines the elimination rate, so the ongoing balance is between the input from absorption and the output by elimination. Metabolism and excretion contribute to how elimination occurs, but the ongoing balance that determines steady-state with successive doses is absorption providing the input.

Absorption. In multiple dosing, steady-state is reached when the rate at which drug enters the body from each dose matches the rate at which it is eliminated. Clearance defines the elimination rate, so the ongoing balance is between the input from absorption and the output by elimination. Metabolism and excretion contribute to how elimination occurs, but the ongoing balance that determines steady-state with successive doses is absorption providing the input.