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Rethinking pharmacokinetics in preterm and term neonates and infants: sex as a critical biological variable

Ilaria Campesi1,2, Andrea Montella1, Flavia Franconi2

  • 1Department of Biomedical Sciences, University of Sassari, Sassari, Italy.

Expert Opinion on Drug Metabolism & Toxicology
|May 11, 2026
PubMed

Insights

Neonates and infants are not small adults. Sex-specific differences in how drugs are processed (pharmacokinetics) are crucial for safe and effective medication in early life.

Area of Science:

  • Pharmacology
  • Pediatrics
  • Developmental Biology

Background:

  • Infants and neonates exhibit rapid physiological development impacting drug processing.
  • Sex is an underrecognized factor influencing drug disposition and response in early life.

Purpose of the Study:

  • To review the ontogeny of drug absorption, distribution, metabolism, and excretion (ADME) in neonates and infants.
  • To evaluate the influence of sex on drug pharmacokinetics (PK) in early life.

Main Methods:

  • Critical evaluation of existing evidence on pediatric ADME.
  • Analysis of factors influencing PK, including age, feeding, microbiota, and formulation.
  • Assessment of sex-specific physiological and enzymatic differences.

Main Results:

  • Significant age-dependent and sex-dependent variations in drug ADME exist.
  • Factors like feeding, microbiota, and drug formulation interact with sex to modulate PK.
  • Limited data, off-label prescribing, and ethical constraints pose challenges.

Conclusions:

  • Recognizing age and sex differences in ADME is vital for optimizing drug safety and efficacy in infants.
  • Physiologically based PK modeling and sex-stratified studies are needed for personalized dosing.
  • Improved strategies are essential for better pediatric drug outcomes.
Abstract

Keywords:
Pharmacokineticsinfantsneonatesontogenysex differences

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