Infants body composition changes

To better understand changes in drug disposition, the pediatric population needs to be categorized into various groups (Table 1) because children vary markedly in their absorption, distribution, metabolism, and elimination of medications. This occurs because neonates, infants, children, adolescents, and adults have different body compositions (i.e., as to their percentages of body water and fat) and have their body organs in different stages of development. 

Changes in body composition seen throughout infancy and childhood have an impact on the apparent volume of distribution (V). Newborn infants have higher total body water on a L/kg basis than older populations therefore, drugs distributed to water have higher V values in newborns when compared to older children... 

Both maternal and infant factors determine the final amount of drug present in the nursing child s body at any particular time. Variations in the daily amount of milk formed within the breast (e.g., changes in blood flow to the breast) as well as alterations in breast mUk pH wUl affect the total amount of drug found in mUk. In addition, composition of the milk will be affected by the maternal diet for example, a high-carbohydrate diet will increase the content of saturated fatty acids in milk. 

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