Pharmacokinetics

Use of physiologically-based pharmacokinetic modeling to inform dosing of the opioid analgesics fentanyl and methadone in children with obesity

Posted on by Kayla Korzekwinski

CPT: Pharmacometrics & Systems Pharmacology • June 2022

Access article on PubMed.

Gerhart JG, Carreno FO, Ford JL, Edginton AN, Perrin EM, Watt KM, Muller WJ, Atz AM, Al-Uzri A, Delmore P, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee
Children with obesity are commonly prescribed the opioids fentanyl and methadone, and accurate dosing is critical to reducing the risk of serious adverse events associated with overexposure. However, there is limited information to guide fentanyl and methadone dosing in these children. This study addresses the clinical knowledge gap using physiologically-based pharmacokinetic models of fentanyl and methadone developed in adults and scaled to children with and without obesity to explore the interplay of obesity, age, and pharmacogenomics.

External Evaluation of Risperidone Population Pharmacokinetic Models Using Opportunistic Pediatric Data

Posted on by Kayla Korzekwinski

Frontiers in Pharmacology • March 2022

Access article on PubMed.

Karatza E, Ganguly S, Hornik CD, Muller MJ, Al-Uzri A, James L, Balevic SJ, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee
Risperidone is approved to treat schizophrenia in adolescents and autistic disorder and bipolar mania in children and adolescents. It is also used off-label in younger children for various psychiatric disorders. The objectives of this study were to assess whether opportunistically collected pediatric data can be used to evaluate risperidone population pharmacokinetic models externally and to identify a robust model for precision dosing in children. All the models had a modest predictive performance, potentially suggesting that sources of inter-individual variability were not entirely captured and that opportunistic data from a highly heterogeneous population are likely not the most appropriate data to evaluate risperidone models externally.

Development and Evaluation of a Virtual Population of Children with Obesity for Physiologically Based Pharmacokinetic Modeling

Posted on by Kayla Korzekwinski

Clinical Pharmacokinetics • February 2022

Access article on PubMed.

Gerhart JG, Carreno FO, Edginton AN, Sinha J, Perrin E, Kumar KR, Rikhi A, Hornik CP, Harris V, Ganguly S, Cohen-Wolkowiez M, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act — Pediatric Trials Network Steering Committee
A virtual population of children with obesity was developed using national survey, electronic health record, and clinical trial data, as well as data extracted from the literature. The objective of this study was to develop a virtual population of children with obesity to enable physiologically based pharmacokinetic modeling, then use the novel virtual population in conjunction with previously developed models of clindamycin and trimethoprim/sulfamethoxazole to better understand dosing of these drugs in children with obesity. Model simulations supported current recommended weight-based dosing in children with obesity for clindamycin and trimethoprim/sulfamethoxazole, as they met target exposure despite these changes in clearance and volume of distribution.

Safety of sildenafil in extremely premature infants: a phase I trial

Posted on by Kayla Korzekwinski

Journal of Perinatology • January 2022

Access article on PubMed.

Jackson W, Gonzalez D, Smith PB, Ambalavanan N, Atz A, Sokol GM, Hornik CD, Stewart D, Mundakel G, Poindexter BB, Ahlfeld SK, Mills M, Cohen-Wolkowiez M, Martz K, Hornik CP, Laughon MM; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee
This study sought to characterize the safety of sildenafil in premature infants. Safety was evaluated based on adverse events (AEs), transaminase levels, and mean arterial pressure monitoring. There was one serious AE related to the study drug involving hypotension associated with a faster infusion rate than specified by the protocol. There were no AEs related to elevated transaminases. Sildenafil was well tolerated by the study population. Drug administration times and flush rates require careful attention to prevent infusion-related hypotension associated with faster infusions of IV sildenafil in premature infants.

External Evaluation of Two Pediatric Population Pharmacokinetics Models of Oral Trimethoprim and Sulfamethoxazole

Posted on by Kayla Korzekwinski

Antimicrobial Agents and Chemotherapy • June 2021

Access article on PubMed.

Wu YSS, Cohen-Wolkowiez M, Hornik CP, Gerhart JG, Autmizguine J, Cobbaert M, Gonzalez D
This study tested the pediatric pharmacokinetics (PK) of the antibiotic combination trimethoprim (TMP)-sulfamethoxazole (SMX) that is used to treat a variety of infections. Both models used supported TMP-SMX dose increases in infants and young children for resistant pathogens with a MIC of 1 mg/liter, although the required dose increase based on the external model was lower.

Prolonged Post-Discontinuation Antibiotic Exposure in Very Low Birth Weight Neonates at Risk for Early-Onset Sepsis

Posted on by Kayla Korzekwinski

Journal of the Pediatric Infectious Diseases Society • May 2021

Access article on PubMed.

Le J, Greenberg RG, Benjamin DK Jr, Yoo Y, Zimmerman KO, Cohen-Wolkowiez M, Wade KC; on behalf of the Administrative Core Committee of the Best Pharmaceuticals for Children Act – Pediatric Trials Network
Premature, very low birth weight neonates are at risk for early-onset sepsis and receive ampicillin and gentamicin post-birth. Antimicrobial stewardship supports short-course antibiotics, but how long antibiotic concentrations remain therapeutic post-last dose is unknown. This study used simulations to examine antibiotic exposures in 34,689 neonates. Therapeutic exposure for ampicillin and gentamicin was evaluated relative to the minimum inhibitory concentration for common pathogens. Ampicillin exposure remains therapeutic long after the last dose. Short-course ampicillin provided therapeutic exposures throughout the typical blood culture incubation period.

Estimation of Body Fat Percentage for Clinical Pharmacokinetic Studies in Children

Posted on by Kayla Korzekwinski

Clinical and Translational Science • March 2021

Access article on PubMed.

Green TP, Binns HJ, Wu H, Ariza AJ, Perrin EM, Quadri M, Hornik CP, Cohen-Wolkowiez M

Obesity is a prevalent childhood condition and the degree of adiposity is likely to be an important covariate in the pharmacokinetics (PKs) of many drugs. The goal of these studies was to facilitate the evaluation and, where appropriate, quantification of the covariate effect of body fat percentage (BF%) on PK parameters in children. Researchers examined two large databases to determine the values and variabilities of BF% in children with healthy body weights and in those with obesity, comparing the accuracy and precision of BF% estimation by both clinical methods and demographically derived techniques. They also conducted simulation studies to evaluate the utility of the several methods for application in clinical trials. The estimation of BF% from sex and obesity stage can routinely be applied to PK clinical trials to evaluate the contribution of BF% as a potential covariate.

Population Pharmacokinetics of Olanzapine in Children

Posted on by Kayla Korzekwinski
British Journal of Clinical Pharmacology • February 2021
Maharaj AR, Wu H, Zimmerman KO, Autmizguine J, Kalra R, Al-Uzri A, Sherwin CMT, Goldstein SL, Watt K, Cohen-Wolkowiez M, Hornik CP; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee
The aim of this study was to evaluate the population pharmacokinetics (PopPK) of olanzapine in children and devise a model-informed pediatric dosing scheme. This analysis is the first study to characterize the PK of olanzapine in participants ranging from infants to adolescents. Body weight and postmenstrual age (PMA) were identified as influential covariates for characterizing developmental changes in olanzapine apparent clearance.

Physiologically-Based Pharmacokinetic Modeling Characterizes the CYP3A-Mediated Drug-Drug Interaction Between Fluconazole and Sildenafil in Infants

Posted on by Kayla Korzekwinski

Clinical Pharmacology & Therapeutics • January 2021

Access article on PubMed.

Salerno SN, Edginton A, Gerhart JG, Laughon MM, Ambalavanan N, Sokol GM, Hornik CD, Stewart D, Mills M, Martz K, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee
Infants being treated for pulmonary hypertension and prevention or treatment of invasive candidiasis may be given sildenafil with fluconazole concurrently. Physiologically-based pharmacokinetic (PBPK) modeling can potentially predict pediatric drug-drug interactions (DDIs) when clinical DDI data are limited. This study highlights the feasibility of PBPK modeling to predict DDIs in infants and the need to include CYP3A7 parameters.

Population Pharmacokinetics of Metoclopramide in Infants, Children, and Adolescents

Posted on by Kayla Korzekwinski

Clinical and Translational Science • November 2020

Access article on PubMed.

Ge S, Mendley SR, Gerhart JG, Melloni C, Hornik CP, Sullivan JE, Atz A, Delmore P, Tremoulet A, Poindexter BB, Harper B, Payne E, Lin S, Erinjeri J, Cohen-Wolkowiez M, Gonzalez D
Metoclopramide is commonly used for gastroesophageal reflux. The aims of the present study were to develop a pediatric population pharmacokinetic (PopPK) model, which was applied to simulate the metoclopramide exposure following dosing used in clinical practice. The study suggests that a metoclopramide dose as previously recommended for pediatric patients results in simulated exposure generally within suggested ranges for the treatment of gastroesophageal reflux.