There are significant contrasts among the preterm neonate, term neonate, and young infant child in drug disposition (absorption, distribution, metabolism, and elimination). Factors, for example, gestational age, body composition, postnatal age, concomitant drug therapy, acidemia/hypoxemia, and end-organ perfusion may influence and convolute drug therapy. Also, developmental issues relate to drug-receptor connections, receptor number, receptor partiality, and receptor guideline and tweak. The neonate is in a fast and persistent condition of maturation, which can impact essentially the restorative and harmful impacts of drug therapy. Our comprehension of the age-and disease- related contrasts in the preterm neonate continues to advance through detailed clinical pharmacokinetic or pharmacodynamic evaluations.