Rifampin Pharmacokinetics and Safety in Preterm and Term Infants

Antimicrobial Agents and Chemotherapy • May 2019.

Smith PB, Cotten CM, Hudak ML, Sullivan JE, Poindexter BB, Cohen-Wolkowiez M, Boakye-Agyeman F, Lewandowski A, Anand R, Benjamin DK Jr, Laughon MM; Best Pharmaceuticals for Children Act—Pediatric Trials Network Steering Committee.

Rifampin is active against methicillin-resistant staphylococcal species and tuberculosis (TB). We performed a multicenter, prospective pharmacokinetic (PK) and safety study of intravenous rifampin in infants of <121 days postnatal age (PNA). We enrolled 27 infants; the median (range) gestational age was 26 weeks (23 to 41 weeks), and the median PNA was 10 days (0 to 84 days). We collected 102 plasma PK samples from 22 of the infants and analyzed safety data from all 27 infants. We analyzed the data using a population PK approach.

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Comparative Analysis of Ampicillin Plasma and Dried Blood Spot Pharmacokinetics in Neonates

Therapeutic Drug Monitoring • February 2018.

Le J, Poindexter B, Sullivan JE, Laughon M, Delmore P, Blackford M, Yogev R, James LP, Melloni C, Harper B, Mitchell J, Benjamin DK Jr, Boakye-Agyeman F, Cohen-Wolkowiez M.

Dried blood spot (DBS) is a practical sampling strategy for pharmacokinetic studies in neonates. The utility of DBS to determine the population pharmacokinetics (pop-PK) of ampicillin, as well as accuracy versus plasma samples, was evaluated. An open-label, multicenter, opportunistic, prospective study was conducted in neonates.

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Population Pharmacokinetics of Trimethoprim-Sulfamethoxazole in Infants and Children

Antimicrobial Agents and Chemotherapy • December 2017.

Autmizguine J, Melloni C, Hornik CP, Dallefeld S, Harper B, Yogev R, Sullivan JE, Atz AM, Al-Uzri A, Mendley S, Poindexter B, Mitchell J, Lewandowski A, Delmore P, Cohen-Wolkowiez M, Gonzalez D; the Pediatric Trials Network Steering Committee.

Trimethoprim (TMP)-sulfamethoxazole (SMX) is used to treat various types of infections, including community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and Pneumocystis jirovecii infections in children. Pharmacokinetic (PK) data for infants and children are limited, and the optimal dosing is not known. We performed a multicenter, prospective PK study of TMP-SMX in infants and children.

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Use of Population Pharmacokinetics and Electronic Health Records to Assess Piperacillin-Tazobactam Safety in Infants

The Pediatric Infectious Disease Journal • September 2017.

Salerno S, Hornik CP, Cohen-Wolkowiez M, Smith PB, Ku LC, Kelly MS, Clark R, Gonzalez D; Best Pharmaceuticals for Children Act–Pediatric Trials Network Steering Committee.

Piperacillin, in combination with tazobactam, is frequently used in infants for treating nosocomial infections, although safety data in this population are limited. Electronic health record (EHR) data can be used to evaluate drug safety in infants, but measures of drug exposure are lacking. To relate simulated piperacillin exposure with adverse events (AEs) in infants using EHR data, we identified infants discharged from 333 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012.

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Pharmacokinetics of Clindamycin in Obese and Nonobese Children

Antimicrobial Agents and Chemotherapy • March 2017.

Smith MJ, Gonzalez D, Goldman JL, Yogev R, Sullivan JE, Reed MD, Anand R, Martz K, Berezny K, Benjamin DK Jr, Smith PB, Cohen-Wolkowiez M, Watt K; Best Pharmaceuticals for Children Act—Pediatric Trials Network Steering Committee.

Although obesity is prevalent among children in the United States, pharmacokinetic (PK) data for obese children are limited. Clindamycin is a commonly used antibiotic that may require dose adjustment in obese children due to its lipophilic properties. We performed a clindamycin population PK analysis using data from three separate trials. A total of 420 samples from 220 children, 76 of whom had a body mass index greater than or equal to the 95th percentile for age, were included in the analysis. Compared to other metrics, total body weight (TBW) was the most robust measure of body size.

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

The Journal of Clinical Pharmacology • February 2017.

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.

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Electronic Health Records and Pharmacokinetic Modeling to Assess the Relationship between Ampicillin Exposure and Seizure Risk in Neonates

Journal of Pediatrics • August 2016.

Hornik CP, Benjamin DK Jr, Smith PB, Pencina MJ, Tremoulet AH, Capparelli EV, Ericson JE, Clark RH, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act—Pediatric Trials Network.

This was a retrospective observational cohort study of electronic health record (EHR) data combined with pharmacokinetic model derived drug exposure predictions. We used the EHR from 348 Pediatrix Medical Group neonatal intensive care units from 1997 to 2012. We included all infants 24-41 weeks gestational age, 500-5400 g birth weight, first exposed to ampicillin prior to 25 days postnatal age. In this cohort of hospitalized infants, higher ampicillin exposure was associated with seizures as documented in the EHR.

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Clindamycin Pharmacokinetics and Safety in Preterm and Term Infants

Antimicrobial Agents and Chemotherapy • April 2016.

Gonzalez D, Delmore P, Bloom BT, Cotten CM, Poindexter BB, McGowan E, Shattuck K, Bradford KK, Smith PB, Cohen-Wolkowiez M, Morris M, Yin W, Benjamin DK Jr, Laughon MM.

Clindamycin may be active against methicillin-resistant Staphylococcus aureus, a common pathogen causing sepsis in infants, but optimal dosing in this population is unknown. We performed a multicenter, prospective pharmacokinetic (PK) and safety study of clindamycin in infants. We analyzed the data using a population PK analysis approach and included samples from two additional pediatric trials.

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Cefepime and Ceftazidime Safety in Hospitalized Infants

The Pediatric Infectious Disease Journal • August 2015.

Arnold CJ, Ericson J, Cho N, Tian J, Wilson S, Chu VH, Hornik CP, Clark RH, Benjamin DK Jr, Smith PB; Best Pharmaceuticals for Children Act–Pediatric Trials Network Administrative Core Committee.

Cefepime and ceftazidime are cephalosporins used for the treatment of serious Gram-negative infections. These cephalosporins are used off-label in the setting of minimal safety data for young infants. We identified all infants discharged from 348 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012 who were exposed to either cefepime or ceftazidime in the first 120 days of life. We reported clinical and laboratory adverse events occurring in infants exposed to cefepime or ceftazidime and used multivariable logistic regression to compare the odds of seizures and death between the 2 groups.

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Use and Safety of Erythromycin and Metoclopramide in Hospitalized Infants

Journal of Pediatric Gastroenterology and Nutrition • August 2015.

Ericson JE, Arnold C, Cheeseman J, Cho J, Kaneko S, Wilson E, Clark RH, Benjamin DK Jr, Chu V, Smith PB, Hornik CP; Best Pharmaceuticals for Children Act–Pediatric Trials Network Administrative Core Committee.

Prokinetic medications are used in premature infants to promote motility and decrease time to full enteral feeding. Erythromycin and metoclopramide are the most commonly used prokinetic medications in the neonatal intensive care unit (NICU), but their safety profile is not well defined.

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