Pharmacokinetics in Pediatric Patients: Drug Excretion

The pediatric population differs in renal function and drug elimination rates from adults.

Newborns have slower renal function, which directly impacts drug clearance and necessitates longer dosing intervals compared to adults.

For instance, drugs with high fractions excreted unchanged in urine require frequent adjustments to prevent drug accumulation and maintain therapeutic concentrations.

On the other hand, aminoglycoside dosing is maturity-dependent, with term newborns requiring a 24-hour dosing interval and preterm newborns needing a 36–48 hour interval.

Meanwhile, in HIV-infected pediatric patients, antiretroviral therapy poses challenges due to diverse pharmacokinetic responses.

Adult antiretroviral fixed-dose combinations may lead to subtherapeutic or toxic concentrations in pediatric patients, requiring dosing adjustments.

For infants and children, the suggested dose of lamivudine is 4 mg/kg of body weight, administered twice daily. In contrast, this dosage is reduced by half for neonates under 28 days old to accommodate their underdeveloped kidney functions.