Rifampin Pharmacokinetics and Safety in Preterm and Term Infants

Antimicrobial Agents and Chemotherapy • May 2019

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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.

Pharmacokinetics of ticarcillin-clavulanate in premature infants

British Journal of Clinical Pharmacology  May 2019

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Watt KM, Hornik CP, Balevic SJ, Mundakel G, Cotten CM, Harper B, Benjamin DK, Anand R, Laughon M, Smith PB, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act Pediatric Trials Network Steering Committee

Ticarcillin-clavulanate covers a broad spectrum of pathogens that are common in premature infants. In infants <30 weeks gestational age, pharmacokinetic data to guide ticarcillin-clavulanate dosing are lacking. This study enrolled premature infants <30 weeks gestational age, determined pharmacokinetic parameters, and performed dosing simulations to determine optimal dosing for ticarcillin-clavulanate.

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

Therapeutic Drug Monitoring • February 2018

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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.

Population Pharmacokinetics of Trimethoprim-Sulfamethoxazole in Infants and Children

Antimicrobial Agents and Chemotherapy • December 2017

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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.

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

The Pediatric Infectious Disease Journal • September 2017

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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.

Pharmacokinetics of Clindamycin in Obese and Nonobese Children

Antimicrobial Agents and Chemotherapy • March 2017

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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.

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

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.

Burden of Invasive Staphylococcus aureus Infections in Hospitalized Infants

JAMA Pediatrics December 2016

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Ericson JE, Popoola VO, Smith PB, Benjamin DK, Benjamin DK Jr, Clark RH, Milstone AM
Staphylococcus aureus is a frequent cause of infection in hospitalized infants. These infections are associated with increased mortality and morbidity, and longer hospital stays, but data on the burden of S. aureus disease in hospitalized infants are limited. This study compared demographics and mortality of infants with invasive methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA), determined the annual proportion of S. aureus infections that were MRSA, and compared the risk of death following an invasive MRSA infection to the risk following an invasive MSSA infection.

Exposure Matching of Pediatric Anti-infective Drugs: Review of Drugs Submitted to the Food and Drug Administration for Pediatric Approval

Clinical Therapeutics September 2016

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Zimmerman K, Putera M, Hornik CP, Smith PB, Benjamin DK Jr, Mulugeta Y, Burckart GJ, Cohen-Wolkowiez M, Gonzalez D

We sought to determine the extent of exposure matching, defined by a comparison of area under the concentration-time curve, between children and adults, for anti-infective drug products submitted to the FDA for approval.

Fluconazole Prophylaxis for the Prevention of Candidiasis in Premature Infants: A Meta-analysis Using Patient-level Data

Clinical Infectious Diseases • August 2016

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Ericson JE, Kaufman DA, Kicklighter SD, Bhatia J, Testoni D, Gao J, Smith PB, Prather KO, Benjamin DK Jr; Fluconazole Prophylaxis Study Team on behalf of the Best Pharmaceuticals for Children Act–Pediatric Trials Network Steering Committee.

Invasive candidiasis (IC) is an important cause of sepsis in premature infants and is associated with a high risk of death and neurodevelopmental impairment. Prevention of IC has become a major focus in very low birth weight infants, with fluconazole increasingly used as prophylaxis. We identified all randomized, placebo-controlled trials evaluating fluconazole prophylaxis in premature infants conducted in the United States.