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First-Order Kinetics

Meaning

First-order kinetics, in the field of pharmacokinetics, describes the process where the rate of drug elimination from the body is directly proportional to the drug concentration currently present in the plasma. This means that a constant fraction or percentage of the drug is eliminated per unit of time, regardless of the total amount. Most hormones and pharmaceutical agents follow this linear kinetic model within their typical therapeutic dose range. This principle is fundamental for determining appropriate dosing regimens and predicting steady-state concentrations.