Final Answer:
Zero-order kinetics means C. Drug is eliminated at a constant rate regardless of dose.
Step-by-step explanation:
Zero-order kinetics in pharmacokinetics refers to a situation where the elimination of a drug occurs at a constant rate, independent of the drug's concentration or dose administered. In this process, a fixed amount of the drug is eliminated per unit of time.
Unlike first-order kinetics, where the elimination is proportional to the drug's concentration, zero-order kinetics implies a linear elimination process. The elimination half-life remains constant, and the rate of elimination is not influenced by changes in the drug's concentration or dosage.
This phenomenon has practical implications in dosing and therapeutic monitoring. With zero-order kinetics, higher doses do not result in a proportional increase in the rate of elimination. Therefore, as the dose increases, the drug accumulates in the body, potentially leading to issues of toxicity. Understanding whether a drug follows zero-order or first-order kinetics is essential for designing appropriate dosage regimens and ensuring safe and effective drug use.
In summary, the correct answer is C, indicating that in zero-order kinetics, a drug is eliminated at a constant rate regardless of the dose administered.