Farmacokinetiek bij pediatrische patiënten: geneesmiddeldistributie

Drug distribution in children is influenced by changes in plasma protein concentration, total body fat, total body water, and extracellular fluid.

Neonates and infants have a higher total body water content and extracellular fluid than adults.

These can affect the distribution of hydrophilic drugs, resulting in lower plasma concentrations in the pediatric population compared to adults.

In contrast, their total body fat is lower at birth, peaks within a year, and then gradually decreases to match the adult levels. However, the distribution volume of lipophilic drugs is less affected.

They also have lower concentrations of plasma proteins, impacting the distribution of drugs that are highly bound to these proteins.

For instance, in neonates and infants, phenytoin has a higher unbound fraction, increasing its plasma concentration and enabling it to exert better activity.

Additionally, in neonates, bilirubin competes with drugs for albumin-binding sites, displacing drugs and increasing the unbound drug fractions.