Placental transfer of diazepam and its disposition in the newborn

M. Mandelli, P. L. Morselli, S. Nordio, G. Pardi, N. Principi, F. Sereni, G. Tognoni

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Diazepam (DZ) placental transfer in pregnant women at term, following single or repeated drug administration by various routes, was evaluated. DZ and its metabolite N-demethyldiazepam (NDZ) were constantly present in umbilical cord plasma at concentrations comparable to the mother's shortly after drug administration. N-methyloxazepam (MOX) was detected in cord plasma only in a limited number of cases following chronic DZ treatment. Postmortem analysis of fetal tissue concentrations showed accumulation of ND Z in heart and lungs. Differences in NDZ concentrations between venous cord (VC) and arterial cord (AC) plasma suggest metabolic degradation of DZ in the fetus. The DZ apparent plasma half-life in the newborn was found to be longer (31 ± 2 hr) than previously observed in infants and children. The low drug clearance appears to be linked to reduced urinary excretion of hydroxylated metabolites, suggesting limited capability to dispose of DZ in the newborn.

Original languageEnglish
Pages (from-to)564-572
Number of pages9
JournalClinical Pharmacology and Therapeutics
Issue number5
Publication statusPublished - May 1975

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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