Multiexponential elimination of gentamicin. A kinetic study during development

Area of Science:

• Pharmacology
• Pediatric Medicine
• Drug Metabolism

Background:

• Gentamicin is a crucial antibiotic for treating bacterial infections in neonates and children.
• Understanding gentamicin's pharmacokinetic profile is essential for optimizing dosing and minimizing toxicity.
• Limited data exists on the long-term disposition of gentamicin in premature newborns.

Purpose of the Study:

• To investigate the long-term disposition and pharmacokinetic parameters of gentamicin in premature newborns and compare them with older infants and children.
• To elucidate age-dependent differences in gentamicin tissue distribution and excretion.

Main Methods:

• Long-term pharmacokinetic study of gentamicin (up to 100-240 hours).
• Inclusion of 13 premature newborns (mean gestational age 33 weeks) and 7 infants/children (1 month to 8 years).
• Data analysis using bi- or triexponential curve fitting to determine pharmacokinetic parameters.

Main Results:

• Gentamicin terminal half-lives averaged 51 hours in newborns and 37 hours in infants/children.
• Newborns demonstrated significantly lower body clearance, central compartment volume, and steady-state volume of distribution compared to older subjects.
• The ratio of gentamicin in tissue to total body at steady state was lower in newborns (0.4) versus older children (0.52).

Conclusions:

• This study provides pharmacokinetic evidence of age-dependent gentamicin tissue distribution and excretion.
• Significant differences in gentamicin disposition exist between premature newborns and older pediatric populations.
• Findings underscore the importance of considering developmental stage in gentamicin therapy for pediatric patients.