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Lopinavir/ritonavir population pharmacokinetics in neonates and infants

Saik Urien1, Ghislaine Firtion, Suzanne T Anderson

  • 1EA 3620, Université Paris Descartes, Paris, France. saik.urien@svp.aphp.fr

British Journal of Clinical Pharmacology
|May 14, 2011
PubMed

Insights

Lopinavir/ritonavir dosing in neonates and infants is weight and post-menstrual age dependent. This study provides optimal dosing regimens for infants from birth to two years to ensure therapeutic drug levels.

Area of Science:

  • Pharmacology
  • Pediatric Medicine
  • Drug Metabolism

Background:

  • Lopinavir/ritonavir pharmacokinetics are well-established in adults and older children.
  • Immature hepatic metabolism in neonates may alter lopinavir pharmacokinetics, necessitating specific dosing considerations.

Purpose of the Study:

  • To determine optimal lopinavir/ritonavir dosing regimens for neonates and infants weighing 1 to 10.5 kg.
  • To investigate the influence of immature hepatic metabolism on lopinavir pharmacokinetics in early life.

Main Methods:

  • Population pharmacokinetic analysis of lopinavir/ritonavir in 96 infants.
  • Utilized a one-compartment model to describe drug pharmacokinetics.
  • Applied allometric scaling to normalize clearance (CL/F) and volume of distribution (V/F) to adult values.

Main Results:

  • Lopinavir/ritonavir clearance and volume of distribution were dependent on body weight and post-menstrual age (PMA).
  • Relative bioavailability increased with PMA, reaching 50% of adult values at 39.7 weeks.
  • Weight and PMA explained variability in CL/F and V/F.

Conclusions:

  • Established weight-based dosing regimens for lopinavir/ritonavir in neonates and infants.
  • Recommended dosages of 40 mg every 12 hours for 1-2 kg, 80 mg every 12 hours for 2-6 kg, and 120 mg every 12 hours for 6-10 kg infants.
  • These regimens aim to achieve adequate trough concentrations based on established limitations.
Abstract

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