Meropenem pharmacokinetics in the newborn

Area of Science:

• Pharmacology
• Neonatal Medicine
• Clinical Pharmacy

Background:

• Neonates, particularly preterm infants, exhibit unique pharmacokinetic profiles for antibiotics.
• Optimizing meropenem dosing is crucial for effective treatment of bacterial infections in neonates.
• Limited data exists on meropenem pharmacokinetics and optimal dosing strategies in diverse neonatal populations.

Purpose of the Study:

• To characterize the population pharmacokinetics of meropenem in preterm and full-term neonates.
• To determine optimal meropenem dosing regimens for achieving therapeutic targets in these populations.
• To evaluate the impact of gestational age and weight on meropenem clearance.

Main Methods:

• Population pharmacokinetic analysis using BigNPAG software.
• Inclusion of estimated creatinine clearance (Schwartz formula) and weight in the pharmacokinetic model.
• Monte Carlo simulations to evaluate various dosing scenarios (20 and 40 mg/kg, 8- and 12-h intervals, 0.5-h and 4-h infusions).

Main Results:

• Meropenem clearance was significantly higher in full-term neonates compared to preterm neonates.
• An 8-hour dosing interval demonstrated robust target attainment for both preterm and full-term neonates.
• Higher doses (40 mg/kg) and prolonged infusions were favored for treating more resistant organisms (MIC 4-8 mg/liter).

Conclusions:

• Meropenem dosing requires careful consideration of patient weight and renal function (creatinine clearance).
• An 8-hour dosing interval appears effective for typical neonatal bacterial infections.
• Higher doses and prolonged infusions may be necessary for challenging infections, balancing efficacy with potential toxicity.