Final answer:
The metabolism of a drug as it passes through the liver is referred to as a pharmacokinetic action. This consists of Phase I and Phase II reactions, such as oxidation, reduction, hydrolysis, and conjugation, and is crucial to the drug's pharmacokinetic profile.
Step-by-step explanation:
The change that occurs in a drug as it passes through the liver is referred to as metabolism. This is a pharmacokinetic action and consists of both Phase I reactions (such as oxidation, reduction, and hydrolysis) and Phase II reactions (such as conjugation). Metabolizing enzymes in the liver, like the cytochrome P450 enzymes (CYP), play a crucial role in this process.
Drugs are converted through these metabolic reactions to substances that are easier for the body to excrete. This mechanism is part of the detoxification process of the body. It's important to account for this during the drug discovery and development process as it can influence the drug's pharmacokinetic profile, which includes its absorption, distribution, metabolism, and excretion (ADME).