When administering medications, a nurse must know a client's medical history and pharmacokinetics of prescribed medications because most drugs are metabolized in the:

Choice A reason: Lungs excrete volatile drugs like anesthetics; most medications aren’t metabolized here, as they lack the cytochrome enzymes needed for broad drug breakdown. Choice B reason: The liver is the primary site; cytochrome P450 enzymes metabolize most drugs, converting them into active or excretable forms, critical for pharmacokinetics. Choice C reason: Kidneys excrete metabolites; they filter, not metabolize, most drugs, relying on prior liver processing, making them secondary in the metabolic pathway. Choice D reason: The colon absorbs some drugs but doesn’t metabolize most; its role is minimal compared to the liver’s extensive enzymatic drug transformation capacity.