Metronidazole

Metronidazole exposure-response and safety in infants

Posted on by Jeannine Sato

Antimicrobial Agents and Chemotherapy, November 2025

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Randell RL, Balevic SJ, Greenberg RG, Cohen-Wolkowiez M, Smith MJ, Benjamin DK Jr, Bendel C, Bliss JM, Chaaban H, Chhabra R, Dammann CEL, Downey LC, Hornik CD, Hussain N, Laughon MM, Lavery A, Moya F, Saxonhouse M, Sokol GM, Trembath A, Weitkamp J-H, Hornik CP; Best Pharmaceuticals for Children Act—Pediatric Trials Network Steering Committee.

The nitroimidazole antibiotic, metronidazole, is frequently prescribed to infants with serious intra-abdominal infections, and multiple dosing recommendations exist. We sought to evaluate the extent to which metronidazole doses and associated exposures achieved desired efficacy and safety in infants enrolled in the Antibiotic Safety in Infants with Complicated Intra-abdominal Infections (SCAMP) trial (NCT01994993). SCAMP participants received intravenous metronidazole as part of multimodal antimicrobial therapy.

Opportunistic dried blood spot sampling validates and optimizes a pediatric population pharmacokinetic model of metronidazole

Posted on by Kayla Korzekwinski

Antimicrobial Agents and Chemotherapy • April 2024

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Randell RL, Balevic SJ, Greenberg RG, Cohen-Wolkowiez M, Thompson EJ, Venkatachalam S, Smith MJ, Bendel C, Bliss JM, Chaaban H, Chhabra R, Dammann CEL, Downey LC, Hornik C, Hussain N, Laughon MM, Lavery A, Moya F, Saxonhouse M, Sokol GM, Trembath A, Weitk

Pharmacokinetic models rarely undergo external validation in vulnerable populations such as critically ill infants, thereby limiting the accuracy, efficacy, and safety of model-informed dosing in real-world settings. Here, we describe an opportunistic approach using dried blood spots (DBS) to evaluate a population pharmacokinetic model of metronidazole in critically ill preterm infants of gestational age (GA) ≤31 weeks from the Metronidazole Pharmacokinetics in Premature Infants study.

Safety of Metronidazole in Late Preterm and Term Infants With Complicated Intraabdominal Infections

Posted on by Kayla Korzekwinski

Pediatric Infectious Disease Journal • September 2020

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Commander SJ, Gao J, Zinkhan EK, Heresi G, Courtney SE, Lavery AP, Delmore P, Sokol GM, Moya F, Benjamin DK Jr, Bumpass TG, Debski J, Erinjeri J, Sharma G, Tracy ET, Cohen-Wolkowiez M, Hornik CP; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee

Metronidazole is frequently used off-label in infants with complicated intra-abdominal infections (cIAI) to provide coverage against anaerobic organisms, but its safety and efficacy in this indication are unknown. Metronidazole safety was evaluated by reporting of adverse events (AEs) and safety events of special interest. In a cohort of late pre-term and term infants with cIAIs, combination antibiotic therapy that included metronidazole was safe, and therapeutic success was high.

Antibiotic Safety and Effectiveness in Premature Infants With Complicated Intraabdominal Infections

Posted on by Kayla Korzekwinski

The Pediatric Infectious Disease Journal • June 2021

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Smith MJ, Boutzoukas A, Autmizguine J, Hudak M, Zinkhan E, Bloom BT, Heresi G, Lavery A, Courtney S, Sokol GR, Cotton CM, Bliss J, Mendley S, Bendel C, Dammann C, Weitkamp JH, Saxonhouse MA, Mundakel GT, Debski J, Lewandowski A, Erinjeri J, Gao J, Benjamin DK, Hornik C, Smith PB, Cohen-Wolkowiez M, on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network
In premature infants, complicated intraabdominal infections (cIAIs) are a leading cause of morbidity and mortality. Although universally prescribed, the safety and effectiveness of commonly used antibiotic regimens have not been established in this population. One hundred eighty infants ≤33 weeks gestational age and <121 days postnatal age with cIAI were randomized to ≤10 days of ampicillin, gentamicin, and metronidazole (group 1); ampicillin, gentamicin, and clindamycin (group 2); or piperacillin-tazobactam and gentamicin (group 3). There were no differences in safety outcomes between antibiotic regimens. Each of the antibiotic regimens are safe in premature infants with cIAI.

Metronidazole Metabolism in Neonates and the Interplay Between Ontogeny and Genetic Variation

Posted on by Kayla Korzekwinski

The Journal of Clinical Pharmacology • February 2017

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Wang LA, Gonzalez D, Leeder JS, Tyndale RF, Pearce RE, Benjamin DK Jr, Kearns GL, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act-Pediatric Trials Network Steering Committee.

Metronidazole is commonly used to treat intra-abdominal infections in neonates. The parent drug is converted to 5 metabolites, with 2-hydroxy-metronidazole being the most clinically significant, as it possesses 30–65% of the antimicrobial activity of the parent compound. In vitro studies have demonstrated that cytochrome P450 2A6 (CYP2A6) is the primary catalyst responsible for metronidazole hydroxylation. This enzyme is initially expressed at low levels at birth, with expression increasing over the course of the first year of life to reach adult levels. CYP2A6 is known to be a highly polymorphic gene with more than 45 variant alleles that result in inactive to ultra-rapid metabolizer phenotypes. Additionally, certain allelic variants such as CYP2A6*17 have amino acid changes that alter metabolism for some but not other substrates, resulting in different metabolizing phenotypes for the same genotype. The role of genetic variation on variable metronidazole metabolism in neonates has not been previously described, nor has the effect of CYP2A6*17 on metronidazole been characterized. As such, the objective of this study was to evaluate the effect of CYP2A6 genetic variation on the pharmacokinetics of metronidazole in a small cohort of preterm neonates.

Anaerobic antimicrobial therapy after necrotizing enterocolitis in VLBW infants

Posted on by Kayla Korzekwinski

Pediatrics • January 2015

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Autmizguine J, Hornik CP, Benjamin DK Jr, Laughon MM, Clark RH, Cotten CM, Cohen-Wolkowiez M, Benjamin DK, Smith PB; Best Pharmaceuticals for Children Act—Pediatric Trials Network Administrative Core Committee.

To evaluate the effect of anaerobic antimicrobial therapy for necrotizing enterocolitis (NEC) on clinical outcomes in very low birth weight (≤1500 g) infants. We identified very low birth weight infants with NEC from 348 US NICUs from 1997 to 2012. Anaerobic antimicrobial therapy was defined by antibiotic exposure on the first day of NEC. We matched (1:1) infants exposed to anaerobic antimicrobial therapy with infants who were not exposed by using a propensity score stratified by NEC severity (medical and surgical).

Intestinal Fatty-Acid Binding Protein and Metronidazole Response in Premature Infants

Posted on by Kayla Korzekwinski

Journal of Neonatal and Perinatal Medicine • November 2014

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Sampson MR, Bloom BT, Arrieta A, Capparelli E, Benjamin DK Jr, Smith PB, Kearns GL, van den Anker J, Cohen-Wolkowiez M.

In premature infants with suspected intra-abdominal infection, biomarkers for treatment response to antimicrobial therapy are lacking. Intestinal fatty acid-binding protein (I-FABP) is specific to the enterocyte and is released in response to intestinal mucosal injury. I-FABP has not been evaluated as a surrogate marker of disease response to antimicrobial therapy. We examined the relationship between metronidazole exposure and urinary I-FABP concentrations in premature infants with suspected intra-abdominal infection.

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

Posted on by Kayla Korzekwinski

The Pediatric Infectious Disease Journal • July 2013

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Cohen-Wolkowiez M, Sampson M, Bloom BT, Arrieta A, Wynn JL, Martz K, Harper B, Kearns GL, Capparelli EV, Siegel D, Benjamin DK Jr, Smith PB; Best Pharmaceuticals for Children Act–Pediatric Trials Network.

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. 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).