After reading this article, the reader should be able to 1. Realize that volume of distribution, elimination clearance, and elimination half-life are crucial parameters of pharmacokinetics that must be understood to determine clinical pharmacologic decisions.2. Know that drug disposition is a complicated process of absorption, distribution,metabolism, and excretion. 3. Understand that any abnormality in absorption, distribution, metabolism, and/or excretion can potentially affect the efficacy or toxicity of a drug. 4. Understand that the anatomical and physiologic changes during development must be considered in predicting age-dependent changes in drug disposition.