Overview of Clinical Pharmacokinetics in Pediatrics: Possible Implications in Therapy

Rapid age-related changes in anatomic and physiologic parameters which may profoundly affect pharmacokinetic variables are characteristics of the first post-natal year and continue thereafter in childhood but to a lesser extent. Allometric methods mostly employed in dosage computation in pediatric age group which regrettably consider children as small adults; should be discarded in favour of the physiologically based pharmacokinetic approach considered far more ideal. Delayed gastric emptying resulting from prolongation in time required to achieve maximal plasma concentration (Tmax) occurs commonly in neonates and infants. Developmental changes that occur in body composition and protein binding are very crucial determinants of drug distribution in the pediatric age group. The pharmacokinetics, clinical efficacy and safety profile of administered drugs in children can be profoundly influenced by the developmental expression profile for the enzymes that support phases 1 and 2 metabolism. The lower rate of drug clearance due to impaired renal blood flow in preterm newborns as compared to normal ones necessitates the need for less frequent dosing interval and lower doses for drugs administered during the neonatal period. In conclusion, the outcome of this review emphasizes the need for understanding changes in developmental pharmacology amongst clinicians, particularly age-related variations in pharmacokinetic processes with obvious implications in enhancing clinical response and minimizing adverse effects.