Determining population and developmental pharmacokinetics of metronidazole using plasma and dried blood spot samples from premature infants

Published

Journal Article

Background: Limited pharmacokinetic (PK) data of metronidazole in premature infants have led to various dosing recommendations. Surrogate efficacy targets for metronidazole are ill-defined and therefore aimed to exceed minimum inhibitory concentration of organisms responsible for intra-abdominal infections. Methods: We evaluated the PK of metronidazole using plasma and dried blood spot samples from infants <32 weeks gestational age in an open-label, PK, multicenter (N = 3) study using population PK modeling (NONMEM). Monte Carlo simulations (N = 1000 virtual subjects) were used to evaluate the surrogate efficacy target. Metabolic ratios of parent and metabolite were calculated. Results: Twenty-four premature infants (111 plasma and 51 dried blood spot samples) were enrolled: median (range) gestational age at birth 25 (23-31) weeks, postnatal age 27 (1-82) days, postmenstrual age 31 (24-39) weeks and weight 740 (431-1466) g. Population clearance (L/h/kg) was 0.038 x (postmenstrual age/30)245 and volume of distribution (L/kg) of 0.93. PK parameter estimates and precision were similar between plasma and dried blood spot samples. Metabolic ratios correlated with clearance. Conclusion: Simulations suggested the majority of infants in the neonatal intensive care unit (>80%) would meet the surrogate efficacy target using postmenstrual age-based dosing. © 2013 by Lippincott Williams & Wilkins.

Full Text

Duke Authors

Cited Authors

  • Cohen-Wolkowiez, M; Sampson, M; Bloom, BT; Arrieta, A; Wynn, JL; Martz, K; Harper, B; Kearns, GL; Capparelli, EV; Siegel, D; Benjamin, DK; Smith, PB

Published Date

  • January 1, 2013

Published In

Volume / Issue

  • 32 / 9

Start / End Page

  • 956 - 961

Electronic International Standard Serial Number (EISSN)

  • 1532-0987

International Standard Serial Number (ISSN)

  • 0891-3668

Digital Object Identifier (DOI)

  • 10.1097/INF0b013e3182947cf8

Citation Source

  • Scopus