Physiology, Zero and First Order Kinetics

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan.


As the human body ingests substances and medications, it utilizes a variety of metabolism and elimination processes. The second focus in this article will be zero and first-order kinetic elimination, which are clinically useful in achieving a therapeutic level of medication and prognostically assessing toxicity levels and implementing treatment. For simplicity, the following discussion will be specific to a one-compartment model, which views the human body as a homogeneous unit. Lastly, while the vast majority of drugs undergo elimination via first-order kinetics, a firm understanding of both zero and first-order kinetics is crucial in a clinical setting, as there can be fluidity between the two types of elimination with the same specific substance.

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