Pharmacology Commons^™

Pediatric Flecainide Pharmacogenomics: A Roadmap To Delivering Precision-Based Care To Pediatrics Arrhythmias., Ronald Palmen, Mollie Walton, Jonathan B. Wagner

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Flecainide acetate is a Class 1c anti-arrhythmic with a potent sodium voltage gated channel blockade which is utilized for the second-line treatment of tachyarrhythmias in children and adults. Given its narrow therapeutic index, the individualization of drug therapy is of utmost importance for clinicians. Despite efforts to improve anti-arrhythmic drug therapy, there remain knowledge gaps regarding the impact of variation in the genes relevant to flecainide's disposition and response. This variability is compounded in developing children whose drug disposition and response pathways may remain immature. The purpose of this comprehensive review is to outline flecainide's disposition and response pathways while …

Pediatric Beta Blocker Therapy: A Comprehensive Review Of Development And Genetic Variation To Guide Precision-Based Therapy In Children, Adolescents, And Young Adults., Mollie Walton, Jonathan B. Wagner

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Beta adrenergic receptor antagonists, known as beta blockers, are one of the most prescribed medications in both pediatric and adult cardiology. Unfortunately, most of these agents utilized in the pediatric clinical setting are prescribed off-label. Despite regulatory efforts aimed at increasing pediatric drug labeling, a majority of pediatric cardiovascular drug agents continue to lack pediatric-specific data to inform precision dosing for children, adolescents, and young adults. Adding to this complexity is the contribution of development (ontogeny) and genetic variation towards the variability in drug disposition and response. In the absence of current prospective trials, the purpose of this comprehensive review …

Developmental Pharmacokinetics Of Indomethacin In Preterm Neonates: Severely Decreased Drug Clearance In The First Week Of Life., Wojciech Krzyzanski, Bradley Stockard, Andrea Gaedigk, Allison Scott, Whitney M. Nolte, Kim T. Gibson, J Steven Leeder, Tamorah Lewis

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Indomethacin is used commonly in preterm neonates for the prevention of intracranial hemorrhage and closure of an abnormally open cardiac vessel. Due to biomedical advances, the infants who receive this drug in the neonatal intensive care unit setting have become younger, smaller, and less mature (more preterm) at the time of treatment. To develop a pharmacokinetics (PK) model to aid future dosing, we designed a prospective cohort study to characterize indomethacin PK in a dynamically changing patient population. A population PK base model was created using NONMEM, and a covariate model was developed in a primary development cohort and subsequently …

Utilization Of The Naranjo Scale To Evaluate Adverse Drug Reactions At A Free-Standing Children's Hospital., Madhavi Murali, Sarah Suppes, Keith Feldman, Jennifer Goldman

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The relationship between the Naranjo scaling system and pediatric adverse drug reactions (ADR) is poorly understood. We performed a retrospective review of 1,676 pediatric ADRs documented at our hospital from 2014-2018. We evaluated patient demographics, implicated medication, ADR severity, calculated Naranjo score, associated symptoms, and location within the hospital in which the ADR was documented. ADR severity was poorly correlated with Naranjo interpretation. Out of the 10 Naranjo scale questions, 4 had a response of "unknown" greater than 85% of the time. Cardiovascular and oncological/immunologic agents were more likely to have a probable or definite Naranjo interpretation compared to antimicrobials. …

Retrospective Review Of Pharmacogenetic Testing At An Academic Children's Hospital., Timothy A. Roberts, Jennifer A. Wagner, Tracy L. Sandritter, Benjamin T. Black, Andrea Gaedigk, Stephani L. Stancil

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There is limited evidence to support pharmacogenetic (PGx) testing in children. We conducted a retrospective review of PGx testing among 452 patients at an academic children's hospital to determine the potential utility of PGx in diseases of childhood and to identify targets for future pediatric pharmacogenetic research. An actionable gene-drug pair associated with the 28 genes tested (Clinical Pharmacogenetics Implementation Consortium (CPIC) level A or B, Pharmacogenomics Knowledge Base (PharmGKB) level 1A or B, or US Food and Drug Administration (FDA) recommendation and a PharmGKB level) was present in 98.7% of patients. We identified 203 actionable gene-drug-diagnosis groups based on …

Effect Of Intrauterine Smoke Exposure On Microrna-15a Expression In Human Lung Development And Subsequent Asthma Risk., Sunita Sharma, Alvin T. Kho, Divya Chhabra, Kathleen Haley, Carrie A. Vyhlidal, R Gaedigk, J Steven Leeder, Kelan G. Tantisira, Benjamin Raby, Scott T. Weiss

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Background: In utero smoke (IUS) exposure is associated with asthma susceptibility.

Objective: We sought to test the hypothesis that changes in miRNA expression by IUS exposure during human lung development is associated with asthma susceptibility.

Methods: Gene expression was profiled from 53 IUS unexposed and 51 IUS exposed human fetal lung tissues. We tested for the differential expression of miRNAs across post-conception age and by IUS using linear models with covariate adjustment. We tested the IUS-associated miRNAs for association with their gene expression targets using pair-wise inverse correlation. Using our mouse model, we investigated the persistence of the IUS-associated miRNA …

Cyp2d6 Predicts Plasma Donepezil Concentrations In A Cohort Of Thai Patients With Mild To Moderate Dementia., Monpat Chamnanphon, Sorawit Wainipitapong, Teeravut Wiwattarangkul, Phenphichcha Chuchuen, Kunathip Nissaipan, Weeraya Phaisal, Sookjaroen Tangwongchai, Chonlaphat Sukasem, Supeecha Wittayalertpanya, Andrea Gaedigk, Daruj Aniwattanapong, Pajaree Chariyavilaskul

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Purpose: Donepezil, a drug frequently used to treat dementia, is mainly metabolized by cytochrome P450 2D6 (CYP2D6). This study investigated the relationships between CYP2D6 genotype and activity scores as well as predicted phenotype of plasma donepezil concentrations in 86 Thai dementia participants.

Materials and methods: CYP2D6 was genotyped using bead-chip technology (Luminex xTAG® v.3). Steady-state trough plasma donepezil concentrations were measured using high-performance liquid chromatography.

Results: Sixteen genotypes were found but the most frequent genotypes detected among our participants were CYP2D6*10/*10 (27.9%) and *1/*10 (26.7%). One-third of the participants had an activity score of 1.25 which predicted that they were …

Ontogeny Related Changes In The Pediatric Liver Metabolome., Christopher M. Wilson, Qian Li, R Gaedigk, Chengpeng Bi, Saskia N. De Wildt, J Steven Leeder, Brooke L. Fridley

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Background: A major challenge in implementing personalized medicine in pediatrics is identifying appropriate drug dosages for children. The majority of drug dosing studies have been based on adult populations, often with modification of the dosing for children based on size and weight. However, the growth and development experienced by children between birth and adulthood represents a dynamically changing biological system, with implications for effective drug dosing, efficacy as well as potential drug toxicity. The purpose of this study was to apply a metabolomics approach to gain preliminary insights into the ontogeny of liver function from newborn to adolescent.

Methods: Metabolites …

Medicine And Media: The Ranitidine Debate., Jennifer A. Wagner, Jennifer Colombo

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Ranitidine has been the topic of recent media reports. Current findings, confirmed by the US Food and Drug Administration, indicate that some ranitidine products contain a substance that may be carcinogenic. Providers and patients require additional information on the risks of continuing therapy vs. the benefits of the medication. This article comments on what is currently known about the evolving situation of elevated N-nitrosodimethylamine levels in ranitidine and the limits of the existing information to assess best practices.

Long-Distance Phasing Of A Tentative "Enhancer" Single-Nucleotide Polymorphism With Yp2d6 Star Allele Definitions, Erin C. Boone, Wendy Y. Wang, R Gaedigk, Mariana Cherner, Anick Bérard, J Steven Leeder, Neil A. Miller, Andrea Gaedigk

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Background: The CYP2D6 gene locus has been extensively studied over decades, yet a portion of variability in CYP2D6 activity cannot be explained by known sequence variations within the gene, copy number variation, or structural rearrangements. It was proposed that rs5758550, located 116 kb downstream of the CYP2D6 gene locus, increases gene expression and thus contributes to variability in CYP2D6 activity. This finding has, however, not been validated. The purpose of the study was to address a major technological barrier, i.e., experimentally linking rs5758550, also referred to as the "enhancer" single-nucleotide polymorphism (SNP), to CYP2D6 haplotypes >100 kb away. To overcome …

The Reliability Of Histamine Pharmacodynamic Response Phenotype Classification In Children With Allergic Disease., Shaun S Kumar, Xiaoxi Liu, Catherine M Sherwin, Bridgette Jones

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We have identified distinct histamine pharmacodynamic response phenotypes in children with allergic disease utilizing histamine iontophoresis with laser Doppler (HILD). These response phenotypes may be relevant in guiding therapeutic decision making for agents targeting the allergic response pathways. However, the reliability of these response phenotypes has not been assessed. Therefore, we performed HILD in children with allergic rhinitis and/or asthma on two to three separate occasions. HILD response-time data were analyzed in NONMEM using a linked effect PKPD model. Examination of observed vs. classified response phenotypes predicted response plots and the sum of residuals. The intraclass correlation coefficient (ICC) was …

Immunogenicity In Clinical Practice And Drug Development: When Is It Significant?, Valentina Shakhnovich, Bernd Meibohm, Amy Rosenberg, Andrzej M. Kierzek, Rachel Hasenkamp, Ryan S. Funk, Craig J. Thalhauser, Piet H. Van Der Graaf, Yow Ming C. Wang, Lora Hamuro

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No abstract provided.

An Electronic Medical Records-Based Approach To Identify Idiosyncratic Drug-Induced Liver Injury In Children., Tracy L. Sandritter, Jennifer Goldman, Clayton J Habiger, James F. Daniel, Jennifer Lowry, Ryan T. Fischer

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Drug-induced liver injury (DILI) is the leading cause of liver failure in the United States and the most common cause of drug recall. As opposed to the recognized direct toxicity of super-therapeutic acetaminophen or chemotherapeutic agents in children, limited data exists for pediatric populations on the incidence of idiosyncratic DILI (iDILI) that may develop independently of drug dose or duration of administration. To improve the detection of adverse drug reactions at our hospital, we utilized electronic medical records-based automated trigger tools to alert providers of potential iDILI. Clinical criteria concerning for iDILI were defined as serum ALT > 5x or serum …

Acetaminophen Protein Adducts In Hospitalized Children Receiving Multiple Doses Of Acetaminophen., Sibo Jiang, Valvanera Vozmediano, Susan M. Abdel-Rahman, Stephan Schmidt, Laura P. James

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Previous reports have questioned the safety of multiple doses of acetaminophen administered to ill children. Acetaminophen protein adducts (adducts) are a biomarker of acetaminophen-induced liver injury and reflect the oxidative metabolism of acetaminophen, a known mechanism in acetaminophen toxicity. In this prospective observational study, we analyzed adduct concentrations in 1034 blood samples obtained from 181 hospitalized children (1 to 18 years inclusive) who received 2 or more doses of acetaminophen. Linear regression analysis showed that serum adduct concentrations increased as a function of the cumulative acetaminophen dose, which could be attributed, in part, to a long half-life of adducts (2.17 …

Developmental Expression Of The Cytosolic Sulfotransferases In Human Liver., Sarah Dubaisi, Joseph A. Caruso, R Gaedigk, Carrie A. Vyhlidal, Philip C. Smith, Ronald N. Hines, Thomas A. Kocarek, Melissa Runge-Morris

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The liver is the predominant organ of metabolism for many endogenous and foreign chemicals. Cytosolic sulfotransferases (SULTs) catalyze the sulfonation of drugs and other xenobiotics, as well as hormones, neurotransmitters, and sterols, with consequences that include enhanced drug elimination, hormone inactivation, and procarcinogen bioactivation. SULTs are classified into six gene families, but only SULT1 and SULT2 enzymes are expressed in human liver. We characterized the developmental expression patterns of SULT1 and SULT2 mRNAs and proteins in human liver samples using reverse transcription quantitative polymerase chain reaction (RT-qPCR), RNA sequencing, and targeted quantitative proteomics. Using a set of prenatal, infant, and …

Proteomics Of Human Liver Membrane Transporters: A Focus On Fetuses And Newborn Infants., Bianca D. Van Groen, Evita Van De Steeg, Miriam G. Mooij, Marola M H Van Lipzig, Barbara A E De Koning, Robert M. Verdijk, Heleen M. Wortelboer, R Gaedigk, Chengpeng Bi, J Steven Leeder, Ron H N Van Schaik, Joost Van Rosmalen, Dick Tibboel, Wouter H. Vaes, Saskia N. De Wildt

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BACKGROUND: Hepatic membrane transporters are involved in the transport of many endogenous and exogenous compounds, including drugs. We aimed to study the relation of age with absolute transporter protein expression in a cohort of 62 mainly fetus and newborn samples.

METHODS: Protein expressions of BCRP, BSEP, GLUT1, MCT1, MDR1, MRP1, MRP2, MRP3, NTCP, OCT1, OATP1B1, OATP1B3, OATP2B1 and ATP1A1 were quantified with LC-MS/MS in isolated crude membrane fractions of snap-frozen post-mortem fetal and pediatric, and surgical adult liver samples. mRNA expression was quantified using RNA sequencing, and genetic variants with TaqMan assays. We explored relationships between protein expression and age …

The Pharmacogene Variation (Pharmvar) Consortium: Incorporation Of The Human Cytochrome P450 (Cyp) Allele Nomenclature Database, Andrea Gaedigk, Magnus Ingelman-Sundberg, Neil A. Miller, J Steven Leeder, Michelle Whirl-Carrillo, Teri E. Klein

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The Human Cytochrome P450 (CYP) Allele Nomenclature Database, a critical resource to the pharmacogenetics and genomics communities, will be transitioning to the Pharmacogene Variation (PharmVar) Consortium. In this report we provide a summary of the current database, provide an overview of the PharmVar consortium and highlight the PharmVar database which will serve as the new home for pharmacogene nomenclature.

Role Of Pharmacogenetics In Improving The Safety Of Psychiatric Care By Predicting The Potential Risks Of Mania In Cyp2d6 Poor Metabolizers Diagnosed With Bipolar Disorder., Santiago Sánchez-Iglesias, Virginia García-Solaesa, Belén García-Berrocal, Almudena Sanchez-Martín, Carolina Lorenzo-Romo, Tomás Martín-Pinto, Andrea Gaedigk, José Manuel González-Buitrago, María Isidoro-García

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One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects.A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip …

Pharmacogenetic Allele Nomenclature: International Workgroup Recommendations For Test Result Reporting., L V. Kalman, Jag Agúndez, M Lindqvist Appell, J L. Black, G C. Bell, S Boukouvala, C Bruckner, E Bruford, K Caudle, S A. Coulthard, A K. Daly, Al Del Tredici, J T. Den Dunnen, K Drozda, R E. Everts, D Flockhart, R R. Freimuth, Andrea Gaedigk, H Hachad, T Hartshorne, M Ingelman-Sundberg, T E. Klein, V M. Lauschke, D R. Maglott, H L. Mcleod, G A. Mcmillin, U A. Meyer, D J. Müller, D A. Nickerson, W S. Oetting, M Pacanowski, V M. Pratt, M V. Relling, A Roberts, W S. Rubinstein, K Sangkuhl, M Schwab, S A. Scott, S C. Sim, R K. Thirumaran, L H. Toji, R F. Tyndale, Rhn Van Schaik, M Whirl-Carrillo, Ktj Yeo, U M. Zanger

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This article provides nomenclature recommendations developed by an international workgroup to increase transparency and standardization of pharmacogenetic (PGx) result reporting. Presently, sequence variants identified by PGx tests are described using different nomenclature systems. In addition, PGx analysis may detect different sets of variants for each gene, which can affect interpretation of results. This practice has caused confusion and may thereby impede the adoption of clinical PGx testing. Standardization is critical to move PGx forward.