Children are not small adults! This phrase has been used by many when referring to use of medications in pediatric patients. It is well recognized that pediatric patients handle medications very differently compared with adults. According to a survey supported by the National Institutes of Health (NIH), there are millions of children who are prescribed medications that don’t have any data on pediatric efficacy or safety.

Drugs are administered in a variety of therapeutic areas using extrapolated dosing data from adult dosing in studies. Recent AAPS Blog posts on pediatric population by Andrew Porterfield, Varsha Bhatt-Mehta, and Prathap Shastri and Jaydeep Yadav emphasize this fact. In the past three decades, much attention has been focused across the globe on the need for expanding pediatric pharmaceutical research. Here we highlight some of the key issues related to development of drug dosing in pediatric patients, including physiologic changes and how they affect the absorption, distribution, metabolism, and excretion (ADME) of drugs. ADME parameters, which are determinants of pharmacokinetics, pharmacodynamics, safety, and efficacy of a drug, are often reported in the literature without any consideration for the influence of simultaneous, ongoing physiologic changes due to growth in children.