The four sequential processes of the pharmacokinetic phase of a medication are:

• A. Biotransformation, absorption, metabolism, excretion
• B. Absorption, distribution, metabolism, excretion
• C. Distribution, absorption, metabolism, excretion
• D. Absorption, Excretion, Distribution, Metabolism

Answer: (B)

The main concept being tested is how a drug moves through the body in a typical pharmacokinetic sequence: absorption, distribution, metabolism, and excretion. Absorption is how the drug enters the bloodstream, which then allows distribution to tissues. After distribution, the body commonly metabolizes the drug, often in the liver, to more water-soluble forms. Finally, excretion eliminates the drug and its metabolites from the body, primarily via the kidneys or biliary system.

This is why the best answer is the sequence: Absorption, Distribution, Metabolism, Excretion. The other options shuffle steps in a way that isn’t physiologically possible—for example, metabolism before absorption suggests the drug never enters the bloodstream to be processed, and excretion before distribution/metabolism would imply elimination before the drug has even been distributed or metabolized.