1
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Milosavljević F, Manojlović M, Matković L, Molden E, Ingelman-Sundberg M, Leucht S, Jukić MM. Pharmacogenetic Variants and Plasma Concentrations of Antiseizure Drugs: A Systematic Review and Meta-Analysis. JAMA Netw Open 2024; 7:e2425593. [PMID: 39115847 PMCID: PMC11310823 DOI: 10.1001/jamanetworkopen.2024.25593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 06/04/2024] [Indexed: 08/11/2024] Open
Abstract
Importance Precise estimation of a patient's drug metabolism capacity is important for antiseizure dose personalization. Objective To quantify the differences in plasma concentrations for antiseizure drugs associated with variants of genes encoding drug metabolizing enzymes. Data Sources PubMed, Clinicaltrialsregister.eu, ClinicalTrials.gov, International Clinical Trials Registry Platform, and CENTRAL databases were screened for studies from January 1, 1990, to September 30, 2023, without language restrictions. Study Selection Two reviewers performed independent study screening and assessed the following inclusion criteria: appropriate genotyping was performed, genotype-based categorization into subgroups was possible, and each subgroup contained at least 3 participants. Data Extraction and Synthesis The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed for data extraction and subsequent quality, validity, and risk-of-bias assessments. The results from the included studies were pooled with random-effect meta-analysis. Main Outcomes and Measures Plasma concentrations of antiseizure drugs were quantified with the dose-normalized area under the concentration-time curve, the dose-normalized steady state concentration, or the concentrations after a single dose at standardized dose and sampling time. The ratio of the means was calculated by dividing the mean drug plasma concentrations of carriers and noncarriers of the pharmacogenetic variant. Results Data from 98 studies involving 12 543 adult participants treated with phenytoin, valproate, lamotrigine, or carbamazepine were analyzed. Studies were mainly conducted within East Asian (69 studies) or White or European (15 studies) cohorts. Significant increases of plasma concentrations compared with the reference subgroup were observed for phenytoin, by 46% (95% CI, 33%-61%) in CYP2C9 intermediate metabolizers, 20% (95% CI, 17%-30%) in CYP2C19 intermediate metabolizers, and 39% (95% CI, 24%-56%) in CYP2C19 poor metabolizers; for valproate, by 12% (95% CI, 4%-20%) in CYP2C9 intermediate metabolizers, 12% (95% CI, 2%-24%) in CYP2C19 intermediate metabolizers, and 20% (95% CI, 2%-41%) in CYP2C19 poor metabolizers; and for carbamazepine, by 12% (95% CI, 3%-22%) in CYP3A5 poor metabolizers. Conclusions and Relevance This systematic review and meta-analysis found that CYP2C9 and CYP2C19 genotypes encoding low enzymatic capacity were associated with a clinically relevant increase in phenytoin plasma concentrations, several pharmacogenetic variants were associated with statistically significant but only marginally clinically relevant changes in valproate and carbamazepine plasma concentrations, and numerous pharmacogenetic variants were not associated with statistically significant differences in plasma concentrations of antiseizure drugs.
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Affiliation(s)
- Filip Milosavljević
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
- Department of Psychiatry and Psychotherapy, School of Medicine, Technische Universität München, München, Germany
| | - Marina Manojlović
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Lena Matković
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
- Institute for Mental Health, Belgrade, Serbia
| | - Espen Molden
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
- Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway
| | - Magnus Ingelman-Sundberg
- Pharmacogenetics Section, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Stefan Leucht
- Department of Psychiatry and Psychotherapy, School of Medicine, Technische Universität München, München, Germany
| | - Marin M. Jukić
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
- Pharmacogenetics Section, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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2
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Guin D, Hasija Y, Kukreti R. Assessment of clinically actionable pharmacogenetic markers to stratify anti-seizure medications. THE PHARMACOGENOMICS JOURNAL 2023; 23:149-160. [PMID: 37626111 DOI: 10.1038/s41397-023-00313-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 07/22/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023]
Abstract
Epilepsy treatment is challenging due to heterogeneous syndromes, different seizure types and higher inter-individual variability. Identification of genetic variants predicting drug efficacy, tolerability and risk of adverse-effects for anti-seizure medications (ASMs) is essential. Here, we assessed the clinical actionability of known genetic variants, based on their functional and clinical significance and estimated their diagnostic predictability. We performed a systematic PubMed search to identify articles with pharmacogenomic (PGx) information for forty known ASMs. Functional annotation of the identified genetic variants was performed using different in silico tools, and their clinical significance was assessed using the American College of Medical Genetics (ACMG) guidelines for variant pathogenicity, level of evidence (LOE) from PharmGKB and the United States-Food and drug administration (US- FDA) drug labelling with PGx information. Diagnostic predictability of the replicated genetic variants was evaluated by calculating their accuracy. A total of 270 articles were retrieved with PGx evidence associated with 19 ASMs including 178 variants across 93 genes, classifying 26 genetic variants as benign/ likely benign, fourteen as drug response markers and three as risk factors for drug response. Only seventeen of these were replicated, with accuracy (up to 95%) in predicting PGx outcomes specific to six ASMs. Eight out of seventeen variants have FDA-approved PGx drug labelling for clinical implementation. Therefore, the remaining nine variants promise for potential clinical actionability and can be improvised with additional experimental evidence for clinical utility.
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Affiliation(s)
- Debleena Guin
- Genomics and Molecular Medicine Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), New Delhi, 110007, India
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Delhi, 110042, India
| | - Yasha Hasija
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Delhi, 110042, India
| | - Ritushree Kukreti
- Genomics and Molecular Medicine Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), New Delhi, 110007, India.
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, 201002, India.
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3
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Prasertsup W, Chomchai S, Mekavuthikul P, Phuditshinnapatra J. Phenytoin Intoxication in a Patient Receiving a Therapeutic Dose for Postoperative Seizure Prophylaxis: A Case Study. Ther Drug Monit 2023; 45:573-575. [PMID: 37705408 DOI: 10.1097/ftd.0000000000001129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 03/10/2023] [Indexed: 09/15/2023]
Abstract
OBJECTIVE Phenytoin is commonly prescribed to prevent postoperative seizures. Despite the rarity of the CYP2C9 genetic polymorphism, which may result in poor phenytoin metabolism, in the Thai population, the authors report a case of phenytoin toxicity in a patient with poor metabolism administered with a standard dose of phenytoin. CASE REPORT A 58-year-old Thai woman presented to the outpatient clinic with a 2-day history of nausea, vomiting, and dizziness. She underwent craniotomy for tumor removal 2 weeks after being diagnosed with tuberculum sellae meningioma. After the surgery, she was prescribed 300 mg of phenytoin daily to prevent seizures. During the physical examination, ataxia, horizontal nystagmus, and cerebellar abnormalities were observed, with an initial serum phenytoin concentration of 58.85 mg/L. The brain imaging results were unremarkable. Omeprazole was the only recognized drug interaction; however, it is highly unlikely to account for this condition. Pharmacogenetic investigation of CYP2C9 revealed a homozygous CYP2C9*3/*3 mutation, which is indicative of suboptimal drug metabolism and can reduce phenytoin metabolism by 50%. This patient was administered repeated dosages of activated charcoal over the course of 2 days. Her symptoms eventually subsided, with the phenytoin levels dropping to 29.51 mg/L. CONCLUSIONS In the absence of an overdose history or drug-drug interaction, CYP2C9 polymorphism should be suspected in patients with phenytoin toxicity. In such situations, the phenytoin dosage must be decreased and monitored closely.
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Affiliation(s)
- Warisa Prasertsup
- Department of Preventive and Social Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Siriraj Poison Control Center, Bangkok, Thailand
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4
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Campbell C, McCormack M, Patel S, Stapleton C, Bobbili D, Krause R, Depondt C, Sills GJ, Koeleman BP, Striano P, Zara F, Sander JW, Lerche H, Kunz WS, Stefansson K, Stefansson H, Doherty CP, Heinzen EL, Scheffer IE, Goldstein DB, O'Brien T, Cotter D, Berkovic SF, Sisodiya SM, Delanty N, Cavalleri GL. A pharmacogenomic assessment of psychiatric adverse drug reactions to levetiracetam. Epilepsia 2022; 63:1563-1570. [PMID: 35298028 PMCID: PMC9321556 DOI: 10.1111/epi.17228] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Levetiracetam (LEV) is an effective antiseizure medicine, but 10%-20% of people treated with LEV report psychiatric side-effects, and up to 1% may have psychotic episodes. Pharmacogenomic predictors of these adverse drug reactions (ADRs) have yet to be identified. We sought to determine the contribution of both common and rare genetic variation to psychiatric and behavioral ADRs associated with LEV. METHODS This case-control study compared cases of LEV-associated behavioral disorder (n = 149) or psychotic reaction (n = 37) to LEV-exposed people with no history of psychiatric ADRs (n = 920). All samples were of European ancestry. We performed genome-wide association study (GWAS) analysis comparing those with LEV ADRs to controls. We estimated the polygenic risk scores (PRS) for schizophrenia and compared cases with LEV-associated psychotic reaction to controls. Rare variant burden analysis was performed using exome sequence data of cases with psychotic reactions (n = 18) and controls (n = 122). RESULTS Univariate GWAS found no significant associations with either LEV-associated behavioural disorder or LEV-psychotic reaction. PRS analysis showed that cases of LEV-associated psychotic reaction had an increased PRS for schizophrenia relative to contr ols (p = .0097, estimate = .4886). The rare-variant analysis found no evidence of an increased burden of rare genetic variants in people who had experienced LEV-associated psychotic reaction relative to controls. SIGNIFICANCE The polygenic burden for schizophrenia is a risk factor for LEV-associated psychotic reaction. To assess the clinical utility of PRS as a predictor, it should be tested in an independent and ideally prospective cohort. Larger sample sizes are required for the identification of significant univariate common genetic signals or rare genetic signals associated with psychiatric LEV ADRs.
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Affiliation(s)
- Ciarán Campbell
- FutureNeuro Research Centre, RCSI Dublin, Dublin, Ireland.,Department of Pharmacy and Biomolecular Science, RCSI Dublin, Dublin, Ireland
| | - Mark McCormack
- Department of Pharmacy and Biomolecular Science, RCSI Dublin, Dublin, Ireland
| | - Sonn Patel
- Department of Psychiatry, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Caragh Stapleton
- Department of Pharmacy and Biomolecular Science, RCSI Dublin, Dublin, Ireland
| | - Dheeraj Bobbili
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Chantal Depondt
- Laboratory of Experimental Neurology, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Graeme J Sills
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Bobby P Koeleman
- Division of Neurosciences, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Pasquale Striano
- Paediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genova, Italy
| | - Federico Zara
- Paediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genova, Italy.,IRCSS, "G. Gaslini" Institute, Genova, Italy
| | - Josemir W Sander
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands.,Department of Clinical & Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Holger Lerche
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Wolfram S Kunz
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Kari Stefansson
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | | | - Colin P Doherty
- FutureNeuro Research Centre, RCSI Dublin, Dublin, Ireland.,Department of Neurology, Beaumont Hospital, Dublin, Ireland
| | - Erin L Heinzen
- School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ingrid E Scheffer
- Royal Children's Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Florey Institute and Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Medicine (Neurology), Epilepsy Research Centre, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, New York, USA
| | - Terence O'Brien
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
| | - David Cotter
- FutureNeuro Research Centre, RCSI Dublin, Dublin, Ireland.,Department of Psychiatry, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Samuel F Berkovic
- Department of Medicine (Neurology), Epilepsy Research Centre, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | | | - Sanjay M Sisodiya
- Department of Clinical & Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Norman Delanty
- FutureNeuro Research Centre, RCSI Dublin, Dublin, Ireland.,Department of Pharmacy and Biomolecular Science, RCSI Dublin, Dublin, Ireland.,Department of Neurology, Beaumont Hospital, Dublin, Ireland
| | - Gianpiero L Cavalleri
- FutureNeuro Research Centre, RCSI Dublin, Dublin, Ireland.,Department of Pharmacy and Biomolecular Science, RCSI Dublin, Dublin, Ireland
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5
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Siddiqui R, Yehia Abouleish M, Khamis M, Ibrahim T, Khan NA. Current medicines hold promise in the treatment of orphan infections due to brain-eating amoebae. Expert Opin Orphan Drugs 2022. [DOI: 10.1080/21678707.2021.2050368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | | | | | - Taleb Ibrahim
- College of Engineering, American University of Sharjah
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, University of Sharjah, University City, Sharjah, United Arab Emirates., University City, Sharjah, United Arab Emirates
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6
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Kanjanasilp J, Sawangjit R, Phanthaisong S, Borihanthanawuth W. A meta-analysis of effects of CYP2C9 and CYP2C19 polymorphisms on phenytoin pharmacokinetic parameters. Pharmacogenomics 2021; 22:629-640. [PMID: 34060344 DOI: 10.2217/pgs-2020-0151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: Phenytoin is metabolized through CYP2C9 and CYP2C19. Polymorphisms of CYP2C9 and CYP2C19 may increase plasma concentration and side effects. Materials & methods: Systematic review and meta-analysis were performed to evaluate the effects of CYP2C9 and CYP2C19 polymorphism on pharmacokinetic parameters. PubMed, Science Direct, Cochrane library, and Thai databases were systematically searched. Results: Eight observational studies, comprising a total of 633 patients were included. Michaelis-Menten constant was significantly higher in the polymorphism of CYP2C9IM/CYP2C19EM and CYP2C9IM/CYP2C19IM groups as compared with the control groups (CYP2C9EM/CYP2C19EM) at 2.16 and 1.55 mg/l (p < 0.00001, p < 0.0001). The maximum rate of action was significantly lower in the control groups as compared with the polymorphism of CYP2C9IM/CYP2C19EM and CYP2C9IM/CYP2C19IM groups at 3.10 and 3.53 mg/kg/day (p = 0.00001, <0.0001). Conclusion: The dosage regimen for patients in the CYP2C9IM group to achieve phenytoin therapeutic levels was 2.1-3.4 mg/kg/day.
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Affiliation(s)
- Juntip Kanjanasilp
- Clinical Trials & Evidence-Based Synthesis Research Unit, Faculty of Pharmacy, Mahasarakham University, Maha Sarakham, 44150, Thailand
| | - Ratree Sawangjit
- Clinical Trials & Evidence-Based Synthesis Research Unit, Faculty of Pharmacy, Mahasarakham University, Maha Sarakham, 44150, Thailand
| | - Sirikhwan Phanthaisong
- Clinical Trials & Evidence-Based Synthesis Research Unit, Faculty of Pharmacy, Mahasarakham University, Maha Sarakham, 44150, Thailand
| | - Wongvaruth Borihanthanawuth
- Clinical Trials & Evidence-Based Synthesis Research Unit, Faculty of Pharmacy, Mahasarakham University, Maha Sarakham, 44150, Thailand
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7
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Karnes JH, Rettie AE, Somogyi AA, Huddart R, Fohner AE, Formea CM, Michael Lee MT, Llerena A, Whirl-Carrillo M, Klein TE, Phillips EJ, Mintzer S, Gaedigk A, Caudle KE, Callaghan JT. Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2C9 and HLA-B Genotypes and Phenytoin Dosing: 2020 Update. Clin Pharmacol Ther 2021; 109:302-309. [PMID: 32779747 PMCID: PMC7831382 DOI: 10.1002/cpt.2008] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/25/2020] [Indexed: 12/19/2022]
Abstract
Phenytoin is an antiepileptic drug with a narrow therapeutic index and large interpatient pharmacokinetic variability, partly due to genetic variation in CYP2C9. Furthermore, the variant allele HLA-B*15:02 is associated with an increased risk of Stevens-Johnson syndrome and toxic epidermal necrolysis in response to phenytoin treatment. We summarize evidence from the published literature supporting these associations and provide therapeutic recommendations for the use of phenytoin based on CYP2C9 and/or HLA-B genotypes (updates on cpicpgx.org).
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Affiliation(s)
- Jason H. Karnes
- Department of Pharmacy Practice & Science, University of Arizona College of Pharmacy, Tucson, AZ, USA; Sarver Heart Center, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Allan E. Rettie
- Department of Medicinal Chemistry, University of Washington School of Pharmacy, Seattle, WA, USA
| | - Andrew A. Somogyi
- Discipline of Pharmacology, Adelaide Medical School, University of Adelaide, Adelaide 5005, Australia
| | - Rachel Huddart
- Department of Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Alison E. Fohner
- Department of Epidemiology, University of Washington, Seattle, WA, USA; Institute of Public Health Genetics, University of Washington, Seattle, WA, USA
| | - Christine M. Formea
- Department of Pharmacy and Intermountain Precision Genomics, Intermountain Healthcare, Salt Lake City, UT, USA
| | | | - Adrian Llerena
- INUBE Extremadura University Biosanitary Research Institute and Medical School, Badajoz, Spain
| | | | - Teri E. Klein
- Department of Biomedical Data Science, Stanford University, Stanford, CA, USA
- Department of Medicine, Stanford University, Stanford, CA, USA
| | - Elizabeth J. Phillips
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Scott Mintzer
- Thomas Jefferson University Hospital Methodist Hospital Division of Thomas Jefferson University Hospital, Department of Neurology, Philadelphia, PA, USA
| | - Andrea Gaedigk
- Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children’s Mercy Kansas City; School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Kelly E. Caudle
- Department of Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - John T. Callaghan
- Department of Veteran Affairs and Departments of Medicine and Pharmacology/Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
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8
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Tang PF, Zheng X, Hu XX, Yang CC, Chen Z, Qian JC, Cai JP, Hu GX. Functional Measurement of CYP2C9 and CYP3A4 Allelic Polymorphism on Sildenafil Metabolism. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:5129-5141. [PMID: 33262574 PMCID: PMC7699448 DOI: 10.2147/dddt.s268796] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/18/2020] [Indexed: 12/20/2022]
Abstract
Aim We aimed to systematically examine the effects of enzymatic activity of 38 human CYP2C9 alleles and 21 human CYP3A4 alleles, including wild-type CYP2C9.1 and CYP3A4.1, which contain the 24 CYP2C9 novel alleles (*36–*60) and 6 CYP3A4 novel alleles (*28–*34) newly found in the Chinese population, on sildenafil metabolism through in vitro experiment. Methods The recombinant cytochrome P450 alleles protein of CYP2C9 and CYP3A4 expressed in insect baculovirus expression system were reacted with 10–500 µM sildenafil for 30 minutes at 37°C, and the reaction was terminated by cooling to −80°C immediately. Next, we used ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection system to detect sildenafil and its active metabolite N-desmethyl sildenafil. Results The intrinsic clearance (Vmax/Km) values of most CYP2C9 variants were significantly altered when compared with the wild-type CYP2C9*1, with most of these variants exhibiting either reduced Vmax and/or increased Km values. Four alleles (CYP2C9*11, *14, *31, *49) exhibited no markedly decreased relative clearance (1-fold). The relative clearance of the remaining thirty-three variants exhibited decrease in different levels, ranging from 1.81% to 88.42%. For the CYP3A4 metabolic pathway, when compared with the wild-type CYP3A4*1, the relative clearance values of four variants (CYP3A4*3, *10, *14 and *I335T) showed significantly higher relative clearance (130.7–134.9%), while five variants (CYP3A4*2, *5, *24, *L22V and *F113I) exhibited sharply reduced relative clearance values (1.80–74.25%), and the remaining nine allelic variants showed no statistical difference. In addition, the kinetic parameters of two CYP3A4 variants (CYP3A4*17 and CYP3A4*30) could not be detected, due to the defect of the CYP3A4 gene. Conclusion These findings were the first evaluation of all these infrequent CYP2C9 and CYP3A4 alleles for sildenafil metabolism; when treating people who carry these CYP2C9 and CYP3A4 variants, there should be more focus on the relation of dose intensity, side effects and therapeutic efficacy when administering sildenafil. The study will provide fundamental data on effect of CYP2C9 and CYP3A4 allelic variation on sildenafil metabolism for further clinical research.
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Affiliation(s)
- Peng-Fei Tang
- Affiliated Yueqing Hospital, Wenzhou Medical University, Wenzhou 325600, Zhejiang, People's Republic of China
| | - Xiang Zheng
- Dong Yang People's Hospital, Jinhua, Zhejiang 322100, People's Republic of China
| | - Xiao-Xia Hu
- Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang 321000, People's Republic of China
| | - Cheng-Cheng Yang
- Ningbo First Hospital, Ningbo 315010, Zhejiang, People's Republic of China
| | - Zhe Chen
- Wenzhou People's Hospital, Wenzhou, Zhejiang 325000, People's Republic of China
| | - Jian-Chang Qian
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325000, Zhejiang, People's Republic of China
| | - Jian-Ping Cai
- The Key Laboratory of Geriatrics, Beijing Hospital and Beijing Institute of Geriatrics, Ministry of Health, Beijing 100730, People's Republic of China
| | - Guo-Xin Hu
- Affiliated Yueqing Hospital, Wenzhou Medical University, Wenzhou 325600, Zhejiang, People's Republic of China.,School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325000, Zhejiang, People's Republic of China
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9
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Chang WC, Hung SI, Carleton BC, Chung WH. An update on CYP2C9 polymorphisms and phenytoin metabolism: implications for adverse effects. Expert Opin Drug Metab Toxicol 2020; 16:723-734. [DOI: 10.1080/17425255.2020.1780209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Wan-Chun Chang
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Shuen-Iu Hung
- Department of Dermatology, Drug Hypersensitivity Clinical and Research Center, Chang Gung Memorial Hospital, Linkou, Taipei, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Cancer Vaccine and Immune Cell Therapy Core Laboratory, Chang Gung Immunology Consortium, Chang Gung Memorial Hospital, Linkou, Taiwan
- Whole-Genome Research Core Laboratory of Human Diseases, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Bruce C Carleton
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Pharmaceutical Outcomes Programme, BC Children’s Hospital, Vancouver, British Columbia, Canada
| | - Wen-Hung Chung
- Department of Dermatology, Drug Hypersensitivity Clinical and Research Center, Chang Gung Memorial Hospital, Linkou, Taipei, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Cancer Vaccine and Immune Cell Therapy Core Laboratory, Chang Gung Immunology Consortium, Chang Gung Memorial Hospital, Linkou, Taiwan
- Whole-Genome Research Core Laboratory of Human Diseases, Chang Gung Memorial Hospital, Keelung, Taiwan
- Department of Dermatology, Xiamen Chang Gung Hospital, Teaching Hospital of School of Medicine, Tsinghua University, China
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10
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Assessing the clinical impact of CYP2C9 pharmacogenetic variation on phenytoin prescribing practice and patient response in an integrated health system. Pharmacogenet Genomics 2020; 29:192-199. [PMID: 31461080 DOI: 10.1097/fpc.0000000000000383] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To assess the impact of CYP2C9 variation on phenytoin patient response and clinician prescribing practice where genotype was unknown during treatment. METHODS A retrospective analysis of Resource on Genetic Epidemiology Research on Adult Health and Aging cohort participants who filled a phenytoin prescription between 1996 and 2017. We used laboratory test results, medication dispensing records, and medical notes to identify associations of CYP2C9 genotype with phenytoin blood concentration, neurologic side effects, and medication dispensing patterns reflecting clinician prescribing practice and patient response. RESULTS Among 993 participants, we identified 69% extensive, 20% high-intermediate, 10% low-intermediate, and 2% poor metabolizers based on CYP2C9 genotypes. Compared with extensive metabolizer genotype, low-intermediate/poor metabolizer genotype was associated with increased dose-adjusted phenytoin blood concentration [21.3 pg/mL, 95% confidence interval (CI): 13.6-29.0 pg/mL; P < 0.01] and increased risk of neurologic side effects (hazard ratio: 2.40, 95% CI: 1.24-4.64; P < 0.01). Decreased function CYP2C9 genotypes were associated with medication dispensing patterns indicating dose decrease, use of alternative anticonvulsants, and worse adherence, although these associations varied by treatment indication for phenytoin. CONCLUSION CYP2C9 variation was associated with clinically meaningful differences in clinician prescribing practice and patient response, with potential implications for healthcare utilization and treatment efficacy.
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11
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Oussalah A, Yip V, Mayorga C, Blanca M, Barbaud A, Nakonechna A, Cernadas J, Gotua M, Brockow K, Caubet J, Bircher A, Atanaskovic‐Markovic M, Demoly P, Kase‐Tanno L, Terreehorst I, Laguna JJ, Romano A, Guéant J, Pirmohamed M. Genetic variants associated with T cell-mediated cutaneous adverse drug reactions: A PRISMA-compliant systematic review-An EAACI position paper. Allergy 2020; 75:1069-1098. [PMID: 31899808 DOI: 10.1111/all.14174] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/27/2019] [Accepted: 10/23/2019] [Indexed: 12/11/2022]
Abstract
Drug hypersensitivity reactions (DHRs) are associated with high global morbidity and mortality. Cutaneous T cell-mediated reactions classically occur more than 6 hours after drug administration and include life-threatening conditions such as toxic epidermal necrolysis, Stevens-Johnson syndrome, and hypersensitivity syndrome. Over the last 20 years, significant advances have been made in our understanding of the pathogenesis of DHRs with the identification of human leukocyte antigens as predisposing factors. This has led to the development of pharmacogenetic screening tests, such as HLA-B*57:01 in abacavir therapy, which has successfully reduced the incidence of abacavir hypersensitivity reactions. We have completed a PRISMA-compliant systematic review to identify genetic associations that have been reported in DHRs. In total, 105 studies (5554 cases and 123 548 controls) have been included in the review reporting genetic associations with carbamazepine (n = 31), other aromatic antiepileptic drugs (n = 24), abacavir (n = 11), nevirapine (n = 14), trimethoprim-sulfamethoxazole (n = 11), dapsone (n = 4), allopurinol (n = 10), and other drugs (n = 5). The most commonly reported genetic variants associated with DHRs are located in human leukocyte antigen genes and genes involved in drug metabolism pathways. Increasing our understanding of genetic variants that contribute to DHRs will allow us to improve diagnosis, develop new treatments, and predict and prevent DHRs in the future.
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Affiliation(s)
- Abderrahim Oussalah
- INSERM UMR_S 1256 NGERE – Nutrition, Genetics, and Environmental Risk Exposure Faculty of Medicine of Nancy University of Lorraine Nancy France
- Department of Molecular Medicine Division of Biochemistry, Molecular Biology, and Nutrition University Hospital of Nancy Nancy France
| | - Vincent Yip
- Department of Molecular and Clinical Pharmacology MRC Centre for Drug Safety Science University of Liverpool Liverpool UK
- Royal Liverpool and Broadgreen University Hospital NHS Trust Liverpool UK
- The Wolfson Centre for Personalized Medicine Institute of Translational Medicine University of Liverpool Liverpool UK
| | - Cristobalina Mayorga
- Allergy Research Group Instituto de Investigación Biomédica de Málaga‐IBIMA‐ARADyAL Málaga Spain
- Allergy Unit Hospital Regional Universitario de Málaga‐ARADyAL Málaga Spain
| | - Miguel Blanca
- Allergy Research Group Instituto de Investigación Biomédica de Málaga‐IBIMA‐ARADyAL Málaga Spain
- Allergy Unit Hospital Regional Universitario de Málaga‐ARADyAL Málaga Spain
| | - Annick Barbaud
- Dermatology and Allergology Department Tenon Hospital (AP‐HP) Sorbonne Universities UPMC University Paris 06 Paris France
| | - Alla Nakonechna
- Allergy and Immunology Clinic Royal Liverpool and Broadgreen University Hospital Liverpool UK
| | - Josefina Cernadas
- Department of Allergy and Clinical Immunology Centro Hospitalar Universitário de Sâo João Porto Portugal
- Allergy Clinic Hospital Lusíadas Porto Portugal
| | - Maia Gotua
- Center for Allergy and Immunology Research Tbilisi Georgia
| | - Knut Brockow
- Klinik für Dermatologie und Allergologie am Biederstein Technische Universität München München Germany
| | | | - Andreas Bircher
- Dermatologie/Allergologie Universitätsspital Basel Basel Switzerland
| | - Marina Atanaskovic‐Markovic
- Medical Faculty Department of Allergology and Pulmonology University Children's Hospital University of Belgrade Belgrade Serbia
| | - Pascal Demoly
- Division of Allergy Department of Pulmonology Hôpital Arnaud de Villeneuve University Hospital of Montpellier Montpellier France
| | | | - Ingrid Terreehorst
- Academisch Medisch Centrum University of Amsterdam Amsterdam Netherlands
| | | | | | - Jean‐Louis Guéant
- INSERM UMR_S 1256 NGERE – Nutrition, Genetics, and Environmental Risk Exposure Faculty of Medicine of Nancy University of Lorraine Nancy France
- Department of Molecular Medicine Division of Biochemistry, Molecular Biology, and Nutrition University Hospital of Nancy Nancy France
| | - Munir Pirmohamed
- Department of Molecular and Clinical Pharmacology MRC Centre for Drug Safety Science University of Liverpool Liverpool UK
- Royal Liverpool and Broadgreen University Hospital NHS Trust Liverpool UK
- The Wolfson Centre for Personalized Medicine Institute of Translational Medicine University of Liverpool Liverpool UK
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12
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Fohner AE, Rettie AE, Thai KK, Ranatunga DK, Lawson BL, Liu VX, Schaefer CA. Associations of CYP2C9 and CYP2C19 Pharmacogenetic Variation with Phenytoin-Induced Cutaneous Adverse Drug Reactions. Clin Transl Sci 2020; 13:1004-1009. [PMID: 32216088 PMCID: PMC7485959 DOI: 10.1111/cts.12787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 02/20/2020] [Indexed: 02/02/2023] Open
Abstract
The role of cytochrome P450 (CYP)2C9 and CYP2C19 genetic variation in risk for phenytoin‐induced cutaneous adverse drug events is not well understood independently of the human leukocyte antigen B (HLA‐B)*15:02 risk allele. In the multi‐ethnic resource for Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort, we identified 382 participants who filled a phenytoin prescription between 2005 and 2017. These participants included 21 people (5%) who self‐identified as Asian, 18 (5%) as black, 29 (8%) as white Hispanic, and 308 (81%) as white non‐Hispanic. We identified 264 (69%) CYP2C9*1/*1, 77 (20%) CYP2C9*1/*2, and 29 (8%) CYP2C9*1/*3. We also determined CYP2C19 genotypes, including 112 with the increased activity CYP2C19*17 allele. Using electronic clinical notes, we identified 32 participants (8%) with phenytoin‐induced cutaneous adverse events recorded within 100 days of first phenytoin dispensing. Adjusting for age, sex, daily dose, and race/ethnicity, participants with CYP2C9*1/*3 or CYP2C9*2/*2 genotypes were more likely to develop cutaneous adverse events compared with CYP2C9*1/*1 participants (odds ratio 4.47; 95% confidence interval 1.64–11.69; P < 0.01). Among participants with low‐intermediate and poor CYP2C9 metabolizer genotypes, eight (22%) who also had extensive and rapid CYP2C19 metabolizer genotypes experienced cutaneous adverse events, compared with none of those who also had intermediate CYP2C19 metabolizer genotypes (P = 0.17). Genetic variation reducing CYP2C9 metabolic activity may increase risk for phenytoin‐induced cutaneous adverse events in the absence of the HLA‐B*15:02 risk allele.
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Affiliation(s)
- Alison E Fohner
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.,Department of Epidemiology, University of Washington, Seattle, Washington, USA.,Institute of Public Health Genetics, University of Washington, Seattle, Washington, USA
| | - Allan E Rettie
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - Khanh K Thai
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
| | - Dilrini K Ranatunga
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
| | - Brian L Lawson
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
| | - Vincent X Liu
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
| | - Catherine A Schaefer
- Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
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Tsai JJ, Ikeda A, Hong SB, Likasitwattanakul S, Dash A. Efficacy, safety, and tolerability of perampanel in Asian and non-Asian patients with epilepsy. Epilepsia 2020; 60 Suppl 1:37-46. [PMID: 30869165 DOI: 10.1111/epi.14642] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 12/13/2018] [Accepted: 12/18/2018] [Indexed: 11/30/2022]
Abstract
People of different ethnic or racial backgrounds may experience variations in pharmacokinetic and pharmacodynamic responses to drug therapies. Our post hoc analysis evaluated the efficacy, safety, and tolerability of perampanel in Asian and non-Asian populations with refractory focal seizures with or without focal to bilateral tonic-clonic (FBTC) seizures. This analysis pooled data from 4 randomized, placebo-controlled, phase-3 studies involving patients aged ≥12 years who have focal seizures with or without FBTC seizures. Patients were receiving 2, 4, 8, or 12 mg perampanel (or placebo) by the end of a 6-week titration period and for a further 13 weeks during the maintenance phase. Efficacy endpoints included median percent change in seizure frequency per 28 days, and 50% and seizure-freedom responder rates relative to baseline. The median percent change in seizure frequency per 28 days from baseline was significantly greater than placebo for perampanel 8 and 12 mg (-31.1% and -38.1% change, respectively; each P < 0.0001) in the Asian population, and for perampanel 4, 8, and 12 mg (-21.1% [P = 0.0001], -26.3% [P < 0.0001], and -27.7% [P = 0.0001] change, respectively) in the non-Asian population. The 50% responder rate relative to baseline was significantly greater than placebo for perampanel 8 and 12 mg (40.1% and 43.8%, respectively; each P < 0.0001) in the Asian population, and for perampanel 4, 8, and 12 mg (29.4% [P = 0.0002], 32.8% [P < 0.0001] and 34.5% [P = 0.0001]), respectively, in the non-Asian population. Seizure-freedom rate among all patients was 4.9%-11.7% for perampanel 2, 4, 8, and 12 mg. The most frequently reported treatment-emergent adverse events (TEAEs) across both populations were dizziness, somnolence, irritability, headache, and fatigue. The most common psychiatric TEAEs were aggression and irritability. Perampanel demonstrated a favorable and similar risk-benefit profile in both Asian and non-Asian populations with refractory focal seizures.
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Affiliation(s)
- Jing-Jane Tsai
- Department of Neurology, National Cheng Kung University Hospital and School of Medicine, National Cheng Kung University, Tainan City, Taiwan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Seung Bong Hong
- Department of Neurology, Samsung Medical Center, Samsung Biomedical Research Institute, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, South Korea
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Li Z, Wang C, Ji S, Jin H, Song G. The Evolution of Population Pharmacokinetic Model of Oral Phenytoin for Early Seizure Prophylaxis Post-Craniotomy. Curr Drug Metab 2019; 20:756-764. [PMID: 31518217 DOI: 10.2174/1389200220666190913115837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/20/2019] [Accepted: 09/02/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND This study aimed to re-establish a Population Pharmacokinetic (PPK) model of oral phenytoin to further optimize the individualized medication regimen based on our previous research. METHODS Patients with intracranial malignant tumor requiring craniotomy were prospectively enrolled according to the inclusion criteria. Genotypes of CYP2C9*1 or *3 and CYP2C19*1, *2 or *3 were determined by real time PCR (TaqMan probe) method. Serum concentrations of phenytoin on the 4th and 7th day after oral administration were determined using fluorescence polarization immunoassay. The PPK parameters were estimated using Nonlinear Mixed Effects Models (NONMEM) and internal validation was performed using bootstraps. The predictive performance of the final model was evaluated by Normalized Predictive Distribution Errors (NPDEs) and diagnostic goodness- of-fit plots. RESULTS A total of 390 serum samples were collected from 170 patients in PPK model building group. The population typical values for Vm, Km and the apparent volume of distribution (V) in the final model were 17.5 mg/h, 6.41 mg/L and 54.8 L, respectively. Internal validation by bootstraps showed that the final model was stable and reliable. NPDEs with a normal distribution and a scatterplot with symmetrical distribution showed that the final model had good predictive capability. Individualized dose regimens of additional 40 patients in the external validation group were designed by the present final PPK model. The percentages of patients with serum concentrations within the therapeutic range were 61.53% (24/39) on the 4th day and 94.87% (37/39) on the 7th day, which were higher than the 39.33% (59/150) and 52.10% (87/167) of above 170 patients (P < 0.0001). CONCLUSION The present PPK final model for oral phenytoin may be used to further optimize phenytoin individualized dose regimen to prevent early seizure in patients after brain injury if patient characteristics meet those of the population studied.
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Affiliation(s)
- Zhongdong Li
- Electric Power Teaching Hospital, Capital Medical University, Beijing 100073, China.,Air Force Clinical School, AnHui Medical University, Hefei 230032, China
| | - Chuan Wang
- Air Force Clinical Department, Chinese PLA General Hospital, Beijing 100000, China
| | - Shuangmin Ji
- Center for Drug Evaluation, National Medical Products Administration, Beijing 100022, China.,School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Hao Jin
- Air Force Clinical School, AnHui Medical University, Hefei 230032, China
| | - Guiqin Song
- Electric Power Teaching Hospital, Capital Medical University, Beijing 100073, China
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Gogou M, Pavlou E. Efficacy of antiepileptic drugs in the era of pharmacogenomics: A focus on childhood. Eur J Paediatr Neurol 2019; 23:674-684. [PMID: 31280948 DOI: 10.1016/j.ejpn.2019.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/23/2019] [Accepted: 06/24/2019] [Indexed: 01/11/2023]
Abstract
BACKGROUND In recent years advances in the field of pharmacogenomics have expanded the concept for more individualized treatments. Our aim is to provide literature data about the relationship between genetic polymorphisms and efficacy of antiepileptic drugs in children. METHODS Pubmed was used as the main medical database source. Only original research papers were considered. No year-of-publication restriction was placed. Quality of evidence was assessed according to American Academy of Neurology guidelines. RESULTS A total of 12 cross-sectional and case-control studies fulfilled our selection criteria. ABCB1 gene was associated with drug responsiveness in 2 out of 6 studies and ABCC2 gene in 1 out of 1 studies. SCN1A gene was also associated with seizure control in 4 out of 5 studies. Cytochrome P450 genes were found to significantly affect drug responsiveness in 2 out of 4 studies, while polymorphisms of uridinediphosphateglucuronosyltransferaseUGT2B7 gene predisposed to drug-resistance in 1 out of 2 studies. CONCLUSION Variability in genes coding for sodium channels, drug transporters and cytochrome P450 enzymes can have a significant impact on response to antiepileptic drugs. Larger prospective studies with better stratification of samples are needed to shed light on these associations.
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Affiliation(s)
- Maria Gogou
- 2nd Department of Pediatrics, University General Hospital AHEPA, Thessaloniki, Greece.
| | - Evangelos Pavlou
- 2nd Department of Pediatrics, University General Hospital AHEPA, Thessaloniki, Greece
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Guk J, Lee SG, Chae D, Kim JH, Park K. Optimal Dosing Regimen of Phenytoin for Korean Epilepsy Patients: From Premature Babies to the Elderly. J Pharm Sci 2019; 108:2765-2773. [DOI: 10.1016/j.xphs.2019.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/24/2019] [Accepted: 03/14/2019] [Indexed: 12/20/2022]
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Pharmacogenomics in Papua New Guineans: unique profiles and implications for enhancing drug efficacy while improving drug safety. Pharmacogenet Genomics 2019; 28:153-164. [PMID: 29768302 DOI: 10.1097/fpc.0000000000000335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Papua New Guinea (PNG) can be roughly divided into highland, coastal and island peoples with significant mitochondrial DNA differentiation reflecting early and recent distinct migrations from Africa and East Asia, respectively. Infectious diseases such as tuberculosis, malaria and HIV severely impact on the health of its peoples for which drug therapy is the major treatment and pharmacogenetics has clinical relevance for many of these drugs. Although there is generally little information about known single nucleotide polymorphisms in the population, in some instances, their frequencies have been shown to be higher than anywhere worldwide. For example, CYP2B6*6 is over 50%, and CYP2C19*2 and *3 are over 40 and 25%, respectively. Conversely, CYP2A6*9, 2B6*2, *3, *4 and *18, and 2C8*3 appear to be much lower than in Whites. CYP2D6 known variants are unclear, and for phase II enzymes, only UGT2B7 and UGT1A9 data are available, with variant frequencies either slightly lower than or similar to Whites. Although almost all PNG people tested are rapid acetylators, but which variant(s) define this phenotype is not known. For HLA-B*13:01, HLA-B*35:05 and HLA-C*04:01, the frequencies show some regioselectivity, but the clinical implications with respect to adverse drug reactions are not known. There are minimal phenotype data for the CYPs and nothing is known about drug transporter or receptor genetics. Determination of genetic variants that are rare in Whites or Asians but common in PNG people is a topic of both scientific and clinical importance, and further research needs to be carried out. Optimizing the safety and efficacy of infectious disease drug therapy through pharmacogenetic studies that have translation potential is a priority.
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Anwar A, Rajendran K, Siddiqui R, Raza Shah M, Khan NA. Clinically Approved Drugs against CNS Diseases as Potential Therapeutic Agents To Target Brain-Eating Amoebae. ACS Chem Neurosci 2019; 10:658-666. [PMID: 30346711 DOI: 10.1021/acschemneuro.8b00484] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Central nervous system (CNS) infections caused by free-living amoebae such as Acanthamoeba species and Naegleria fowleri are rare but fatal. A major challenge in the treatment against the infections caused by these amoebae is the discovery of novel compounds that can effectively cross the blood-brain barrier to penetrate the CNS. It is logical to test clinically approved drugs against CNS diseases for their potential antiamoebic effects since they are known for effective blood-brain barrier penetration and affect eukaryotic cell targets. The antiamoebic effects of clinically available drugs for seizures targeting gamma-amino butyric acid (GABA) receptor and ion channels were tested against Acanthamoeba castellanii belonging to the T4 genotype and N. fowleri. Three such drugs, namely, diazepam (Valium), phenobarbitone (Luminal), phenytoin (Dilantin), and their silver nanoparticles (AgNPs) were evaluated against both trophozoites and cysts stage. Drugs alone and drug conjugated silver nanoparticles were tested for amoebicidal, cysticidal, and host-cell cytotoxicity assays. Nanoparticles were synthesized by sodium borohydride reduction of silver nitrate with drugs as capping agents. Drug conjugated nanoconjugates were characterized by ultraviolet-visible (UV-vis) and Fourier transform infrared (FT-IR) spectroscopies and atomic force microscopy (AFM). In vitro moebicidal assay showed potent amoebicidal effects for diazepam, phenobarbitone, and phenytoin-conjugated AgNPs as compared to drugs alone against A. castellanii and N. fowleri. Furthermore, both drugs and drug conjugated AgNPs showed compelling cysticidal effects. Drugs conjugations with silver nanoparticles enhanced their antiacanthamoebic activity. Interestingly, amoeba-mediated host-cell cytotoxicity was also significantly reduced by drugs alone as well as their nanoconjugates. Since, these drugs are being used to target CNS diseases, their evaluation against brain-eating amoebae seems feasible due to advantages such as permeability of the blood-brain barrier, established pharmacokinetics and dynamics, and United States Food and Drug Administration (FDA) approval. Given the limited availability of effective drugs against brain-eating amoebae, the clinically available drugs tested here present potential for further in vivo studies.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Kavitha Rajendran
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Muhammad Raza Shah
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
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Franceschini N, Frick A, Kopp JB. Genetic Testing in Clinical Settings. Am J Kidney Dis 2018; 72:569-581. [PMID: 29655499 PMCID: PMC6153053 DOI: 10.1053/j.ajkd.2018.02.351] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 02/20/2018] [Indexed: 12/16/2022]
Abstract
Genetic testing is used for screening, diagnosis, and prognosis of diseases consistent with a genetic cause and to guide drug therapy to improve drug efficacy and avoid adverse effects (pharmacogenomics). This In Practice review aims to inform about DNA-related genetic test availability, interpretation, and recommended clinical actions based on results using evidence from clinical guidelines, when available. We discuss challenges that limit the widespread use of genetic information in the clinical care setting, including a small number of actionable genetic variants with strong evidence of clinical validity and utility, and the need for improving the health literacy of health care providers and the public, including for direct-to-consumer tests. Ethical, legal, and social issues and incidental findings also need to be addressed. Because our understanding of genetic factors associated with disease and drug response is rapidly increasing and new genetic tests are being developed that could be adopted by clinicians in the short term, we also provide extensive resources for information and education on genetic testing.
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Affiliation(s)
- Nora Franceschini
- Department of Epidemiology, Gillings School of Public Health, University of North Carolina, Chapel Hill, NC.
| | - Amber Frick
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC
| | - Jeffrey B Kopp
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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Pharmacokinetic Factors to Consider in the Selection of Antiseizure Drugs for Older Patients with Epilepsy. Drugs Aging 2018; 35:687-698. [DOI: 10.1007/s40266-018-0562-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Silvado CE, Terra VC, Twardowschy CA. CYP2C9 polymorphisms in epilepsy: influence on phenytoin treatment. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2018; 11:51-58. [PMID: 29636628 PMCID: PMC5880189 DOI: 10.2147/pgpm.s108113] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Phenytoin (PHT) is an antiepileptic drug widely used in the treatment of focal epilepsy and status epilepticus, and effective in controlling focal seizures with and without tonic-clonic generalization and status epilepticus. The metabolization of PHT is carried out by two oxidative cytochrome P450 enzymes CYP2C9 and CYP2C19; 90% of this metabolization is done by CYP2C9 and the remaining 10% by CYP2C19. Genetic polymorphism of CYP2C9 may reduce the metabolism of PHT by 25-50% in patients with variants *2 and *3 compared to those with wild-type variant *1. The frequency distribution of CYP2C9 polymorphism alleles in patients with epilepsy around the world ranges from 4.5 to 13.6%, being less frequent in African-Americans and Asians. PHT has a narrow therapeutic range and a nonlinear pharmacokinetic profile; hence, its poor metabolization has significant clinical implications as it causes more frequent and more serious adverse effects requiring discontinuation of treatment, even if it had been effective. There is evidence that polymorphisms of CYP2C9 and the use of PHT are associated with an increase in the frequency of some side effects, such as cerebellar atrophy, gingival hypertrophy or acute cutaneous reactions. The presence of HLA-B*15:02 and CYP2C9 *2 or *3 in the same patient increases the risk of Stevens-Johnson syndrome and toxic epidermal necrolysis; hence, PHT should not be prescribed in these patients. In patients with CYP2C9 *1/*2 or *1/*3 alleles (intermediate metabolizers), the usual PHT maintenance dose (5-10 mg/kg/day) must be reduced by 25%, and in those with CYP2C9 *2/*2, *2/*3 or *3/*3 alleles (poor metabolizers), the dose must be reduced by 50%. It is controversial whether CYP2C9 genotyping should be done before starting PHT treatment. In this paper, we aim to review the influence of CYP2C9 polymorphism on the metabolization of PHT and the clinical implications of poor metabolization in the treatment of epilepsies.
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Affiliation(s)
- Carlos Eduardo Silvado
- Comprehensive Epilepsy Program, Hospital de Clinicas, Federal University of Parana (UFPR), Curitiba, Brazil
| | - Vera Cristina Terra
- Comprehensive Epilepsy Program, Hospital de Clinicas, Federal University of Parana (UFPR), Curitiba, Brazil
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Dagenais R, Wilby KJ, Elewa H, Ensom MHH. Impact of Genetic Polymorphisms on Phenytoin Pharmacokinetics and Clinical Outcomes in the Middle East and North Africa Region. Drugs R D 2017; 17:341-361. [PMID: 28748348 PMCID: PMC5629135 DOI: 10.1007/s40268-017-0195-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Genetic polymorphisms are known to influence outcomes with phenytoin yet effects in the Middle East and North Africa region are poorly understood. OBJECTIVES The objective of this systematic review was to evaluate the impact of genetic polymorphisms on phenytoin pharmacokinetics and clinical outcomes in populations originating from the Middle East and North Africa region, and to characterize genotypic and allelic frequencies within the region for genetic polymorphisms assessed. METHODS MEDLINE (1946-3 May, 2017), EMBASE (1974-3 May, 2017), Pharmacogenomics Knowledge Base, and Public Health Genomics Knowledge Base online databases were searched. Studies were included if genotyping and analyses of phenytoin pharmacokinetics were performed in patients of the Middle East and North Africa region. Study quality was assessed using a National Institutes of Health assessment tool. A secondary search identified studies reporting genotypic and allelic frequencies of assessed genetic polymorphisms within the Middle East and North Africa region. RESULTS Five studies met the inclusion criteria. CYP2C9, CYP2C19, and multidrug resistance protein 1 C3435T variants were evaluated. While CYP2C9*2 and *3 variants significantly reduced phenytoin metabolism, the impacts of CYP2C19*2 and *3 variants were unclear. The multidrug resistance protein 1 CC genotype was associated with drug-resistant epilepsy, but reported impacts on phenytoin pharmacokinetics were conflicting. Appreciable variability in minor allele frequencies existed both between and within countries of the Middle East and North Africa region. CONCLUSIONS CYP2C9 decrease-of-function alleles altered phenytoin pharmacokinetics in patients originating from the Middle East and North Africa region. The impacts of CYP2C19 and multidrug resistance protein 1 C3435T variants on phenytoin pharmacokinetic and clinical outcomes are unclear and require further investigation. Future research should focus on the clinical outcomes associated with phenytoin therapy. PROSPERO 2017: CRD42017057850.
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Affiliation(s)
- Renée Dagenais
- Faculty of Pharmaceutical Sciences, Pharmaceutical Sciences Building, University of British Columbia, Vancouver, BC, Canada
| | - Kyle John Wilby
- College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar.
| | - Hazem Elewa
- College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar
| | - Mary H H Ensom
- Faculty of Pharmaceutical Sciences, Pharmaceutical Sciences Building, University of British Columbia, Vancouver, BC, Canada
- Department of Pharmacy, Children's and Women's Health Centre of British Columbia, Vancouver, BC, Canada
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Role of CYP2C9, CYP2C19 and EPHX Polymorphism in the Pharmacokinetic of Phenytoin: A Study on Uruguayan Caucasian Subjects. Pharmaceuticals (Basel) 2017; 10:ph10030073. [PMID: 28820457 PMCID: PMC5620617 DOI: 10.3390/ph10030073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 01/15/2023] Open
Abstract
Phenytoin (PHT) oxidative route leads to its main metabolite p-hydroxyphenytoin (p-HPPH), by means of CYP2C9 and CYP2C19. Formation of p-HPPH proceeds via a reactive arene-oxide intermediate. This intermediate can also be converted into PHT dihydrodiol by microsomal epoxide hydrolase (EPHX). The three enzymes are polymorphically expressed and the genetic variants are responsible for changes in the enzyme activity. In order to evaluate the effect that these polymorphisms have on PHT metabolism, PHT and p-HPPH plasma concentrations were measured and the genotype for the three enzymes was assessed in 50 Uruguayan epileptic patients. 30% of the patients were intermediate and 2% were poor metabolizers for CYP2C9, while 20% were intermediate metabolizers for CYP2C19. 44%, 10%, and 46% of subjects had intermediate, increased and decreased activities of EPHX respectively. CYP2C9 was confirmed to be the main responsible enzyme for PHT biotransformation. CYP2C19 seemed to be preponderant in p-HPPH oxidative metabolism. Apart from being responsible for the production of the dihydrodiol metabolite, EPHX also seemed to contribute to pHPPH formation when its activity is low. PHT might be recovered with a decreased activity of EPHX regardless the activity of CYP2C9.
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Influence of genetic variants of CYP2D6, CYP2C9, CYP2C19 and CYP3A4 on antiepileptic drug metabolism in pediatric patients with refractory epilepsy. Pharmacol Rep 2017; 69:504-511. [DOI: 10.1016/j.pharep.2017.01.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 01/10/2017] [Accepted: 01/16/2017] [Indexed: 12/11/2022]
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Ku LC, Wu H, Greenberg RG, Hill KD, Gonzalez D, Hornik CP, Berezny A, Guptill JT, Jiang W, Zheng N, Cohen-Wolkowiez M, Melloni C. Use of Therapeutic Drug Monitoring, Electronic Health Record Data, and Pharmacokinetic Modeling to Determine the Therapeutic Index of Phenytoin and Lamotrigine. Ther Drug Monit 2016; 38:728-737. [PMID: 27764025 PMCID: PMC5113813 DOI: 10.1097/ftd.0000000000000354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Defining a drug's therapeutic index (TI) is important for patient safety and regulating the development of generic drugs. For many drugs, the TI is unknown. A systematic approach was developed to characterize the TI of a drug using therapeutic drug monitoring and electronic health record (EHR) data with pharmacokinetic (PK) modeling. This approach was first tested on phenytoin, which has a known TI, and then applied to lamotrigine, which lacks a defined TI. METHODS Retrospective EHR data from patients in a tertiary hospital were used to develop phenytoin and lamotrigine population PK models and to identify adverse events (anemia, thrombocytopenia, and leukopenia) and efficacy outcomes (seizure-free). Phenytoin and lamotrigine concentrations were simulated for each day with an adverse event or seizure. Relationships between simulated concentrations and adverse events and efficacy outcomes were used to calculate the TI for phenytoin and lamotrigine. RESULTS For phenytoin, 93 patients with 270 total and 174 free concentrations were identified. A de novo 1-compartment PK model with Michaelis-Menten kinetics described the data well. Simulated average total and free concentrations of 10-15 and 1.0-1.5 mcg/mL were associated with both adverse events and efficacy in 50% of patients, resulting in a TI of 0.7-1.5. For lamotrigine, 45 patients with 53 concentrations were identified. A published 1-compartment model was adapted to characterize the PK data. No relationships between simulated lamotrigine concentrations and safety or efficacy endpoints were seen; therefore, the TI could not be calculated. CONCLUSIONS This approach correctly determined the TI of phenytoin but was unable to determine the TI of lamotrigine due to a limited sample size. The use of therapeutic drug monitoring and EHR data to aid in narrow TI drug classification is promising, but it requires an adequate sample size and accurate characterization of concentration-response relationships.
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Affiliation(s)
- Lawrence C. Ku
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Huali Wu
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Rachel G. Greenberg
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Kevin D. Hill
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Daniel Gonzalez
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Christoph P. Hornik
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Alysha Berezny
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Jeffrey T. Guptill
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Wenlei Jiang
- Office of Generic Drugs, US Food and Drug Administration, Silver Spring, MD, USA
| | - Nan Zheng
- Office of Generic Drugs, US Food and Drug Administration, Silver Spring, MD, USA
| | - Michael Cohen-Wolkowiez
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chiara Melloni
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA
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Fricke-Galindo I, Ortega-Vázquez A, Monroy-Jaramillo N, Dorado P, Jung-Cook H, Peñas-Lledó E, LLerena A, López-López M. Allele and genotype frequencies of genes relevant to anti-epileptic drug therapy in Mexican-Mestizo healthy volunteers. Pharmacogenomics 2016; 17:1913-1930. [PMID: 27790929 DOI: 10.2217/pgs-2016-0078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
AIM To determine allele and genotype frequencies of genes influencing anti-epileptic drug therapy in Mexican-Mestizo (MM) healthy volunteers, and to evaluate whether these are different from those reported for other populations. SUBJECTS & METHODS Thirty-nine variants of CYP3A5, EPHX1, NR1I2, HNF4A, UGT1A1, UGT2B7, ABCC2, RALBP1, SCN1A, SCN2A and GABRA1 were genotyped in 300 MM healthy volunteers. RESULTS All studied alleles were presented in MM, except for seven UGT1A1 variants (*6-8, 14, 15, 27 and 29). Allele and genotype frequencies showed interethnic variations when compared with European, Asian and African populations. Allele frequencies of greater than 30% were observed in ten genes. CONCLUSION The results presented regarding the frequencies and interethnic differences of these polymorphisms should be taken into account for future pharmacogenetic studies of anti-epileptic drugs in MM patients with epilepsy.
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Affiliation(s)
- Ingrid Fricke-Galindo
- Doctorate in Biological & Health Sciences, Metropolitan Autonomous University, Campus Xochimilco, Mexico City, Mexico
| | - Alberto Ortega-Vázquez
- Department of Biological Systems, Metropolitan Autonomous University, Campus Xochimilco, Mexico City, Mexico
| | - Nancy Monroy-Jaramillo
- Department of Neurogenetics & Molecular Biology, National Institute of Neurology & Neurosurgery Manuel Velasco Suárez, Mexico City, Mexico
| | - Pedro Dorado
- CICAB Clinical Research Centre, Extremadura University Hospital & Medical School, Servicio Extremeño de Salud, Badajoz, Spain
| | - Helgi Jung-Cook
- Department of Pharmacy, Chemistry Faculty, National Autonomous University of Mexico, Mexico City, Mexico.,Department of Neuropharmacology, National Institute of Neurology & Neurosurgery Manuel Velasco Suárez, Mexico City, Mexico
| | - Eva Peñas-Lledó
- CICAB Clinical Research Centre, Extremadura University Hospital & Medical School, Servicio Extremeño de Salud, Badajoz, Spain
| | - Adrián LLerena
- CICAB Clinical Research Centre, Extremadura University Hospital & Medical School, Servicio Extremeño de Salud, Badajoz, Spain
| | - Marisol López-López
- Department of Biological Systems, Metropolitan Autonomous University, Campus Xochimilco, Mexico City, Mexico
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Comparing paediatric intravenous phenytoin doses using physiologically based pharmacokinetic (PBPK) modelling software. Seizure 2015; 33:8-12. [DOI: 10.1016/j.seizure.2015.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/11/2015] [Accepted: 10/12/2015] [Indexed: 11/21/2022] Open
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CYP2C9, CYP2C19, ABCB1 genetic polymorphisms and phenytoin plasma concentrations in Mexican-Mestizo patients with epilepsy. THE PHARMACOGENOMICS JOURNAL 2015; 16:286-92. [DOI: 10.1038/tpj.2015.45] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 05/14/2015] [Accepted: 05/21/2015] [Indexed: 01/11/2023]
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Franco V, Perucca E. CYP2C9 polymorphisms and phenytoin metabolism: implications for adverse effects. Expert Opin Drug Metab Toxicol 2015; 11:1269-79. [DOI: 10.1517/17425255.2015.1053463] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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30
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Individualized Phenytoin Therapy for Japanese Pediatric Patients With Epilepsy Based on CYP2C9 and CYP2C19 Genotypes. Ther Drug Monit 2015; 37:229-35. [DOI: 10.1097/ftd.0000000000000128] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Seven M, Batar B, Unal S, Yesil G, Yuksel A, Guven M. The effect of genetic polymorphisms of cytochrome P450 CYP2C9, CYP2C19, and CYP2D6 on drug-resistant epilepsy in Turkish children. Mol Diagn Ther 2014; 18:229-36. [PMID: 24338437 DOI: 10.1007/s40291-013-0078-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVE Despite the availability of several antiepileptic drugs, drug resistance remains one of the major challenges in epilepsy therapy. Genetic factors are known to play a significant role in the prognosis and treatment of epilepsy. The aim of this study was to determine the frequencies of alleles for CYP2C9, CYP2C19, and CYP2D6 genes in Turkish children with epilepsy, and to investigate the relationship between the genetic polymorphism of these genes with multiple drug resistance in epilepsy patients. METHODS We genotyped 132 epileptic patients (60 drug resistant and 72 drug responsive) and 55 healthy controls for six single nucleotide polymorphisms (SNPs) in CYP2C9, CYP2C19, and CYP2D6. Genotype, allele, and haplotype frequencies were compared between groups. RESULTS The frequencies of CYP2C9*3/*3 genotype and CYP2C9*3 allele, and the haplotype CCGG (CYP2C9*2 C>T, CYP2C9*3 A>C, and CYP2C19*2 G>A, CYP2C19* G>A) were significantly higher in drug-resistant versus -responsive patients. CONCLUSION Our results demonstrated the important role of the CYP2C9*3 allelic variant in preventing epilepsy patients from developing drug resistance. These data suggest that CYP2C9, CYP2C19, and CYP2D6 SNPs and haplotypes may affect the response to antiepileptic drugs.
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Affiliation(s)
- Mehmet Seven
- Department of Medical Genetics, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
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Mann M, Chhun S, Pons G. Farmacogenetica dei farmaci antiepilettici. Neurologia 2014. [DOI: 10.1016/s1634-7072(14)68868-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Ozkaynakci A, Gulcebi MI, Ergeç D, Ulucan K, Uzan M, Ozkara C, Guney I, Onat FY. The effect of polymorphic metabolism enzymes on serum phenytoin level. Neurol Sci 2014; 36:397-401. [PMID: 25311916 DOI: 10.1007/s10072-014-1961-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/18/2014] [Indexed: 10/24/2022]
Abstract
Phenytoin has a widespread use in epilepsy treatment and is mainly metabolized by hepatic cytochrome P450 enzymes (CYP). We have investigated CYP2C9*2, CYP2C9*3, CYP2C19*2 and CYP2C19*3 allelic variants in a Turkish population of patients on phenytoin therapy. Patients on phenytoin therapy (n = 102) for the prevention of epileptic seizures were included. Polymorphic alleles were analyzed by restriction fragment length polymorphism method. Serum concentrations of phenytoin were measured by fluorescence polarization immune assay method. The most frequent genotype was detected for CYP2C9 wild-type alleles (78.43 %), whereas CYP2C19*2/*2 (5.88 %) was the least frequent genotype group. According to the classification made with both enzyme polymorphisms, CYP2C9*1/*1-CYP2C19*1/*1 (G1: 41.17 %) genotype group was the most frequent whereas CYP2C9*1/*2-CYP2C19*1/*3 (G7: 0.98 %) was the least frequent one. The highest mean phenytoin level (27.95 ± 1.85 µg/ml) was detected in the G8 genotype group (CYP2C9*1/*3-CYP2C19*2/*3) and the G1 genotype group showed the lowest mean phenytoin level (7.43 ± 0.73 µg/ml). The mean serum concentration of phenytoin of the polymorphic patients with epilepsy was higher than that for the wild-type alleles both in the monotherapy and polytherapy patients. These results show the importance of the genetic polymorphism analysis of the main metabolizing enzyme groups of phenytoin for the dose adjustment.
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Affiliation(s)
- Aydan Ozkaynakci
- Department of Pharmacology, School of Medicine, University of Marmara, Istanbul, Turkey
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Caudle KE, Rettie AE, Whirl-Carrillo M, Smith LH, Mintzer S, Lee MTM, Klein TE, Callaghan JT. Clinical pharmacogenetics implementation consortium guidelines for CYP2C9 and HLA-B genotypes and phenytoin dosing. Clin Pharmacol Ther 2014; 96:542-8. [PMID: 25099164 DOI: 10.1038/clpt.2014.159] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/31/2014] [Indexed: 01/21/2023]
Abstract
Phenytoin is a widely used antiepileptic drug with a narrow therapeutic index and large interpatient variability, partly due to genetic variations in the gene encoding cytochrome P450 (CYP)2C9 (CYP2C9). Furthermore, the variant allele HLA-B*15:02, encoding human leukocyte antigen, is associated with an increased risk of Stevens-Johnson syndrome and toxic epidermal necrolysis in response to phenytoin treatment. We summarize evidence from the published literature supporting these associations and provide recommendations for the use of phenytoin based on CYP2C9 and/or HLA-B genotype (also available on PharmGKB: http://www.pharmgkb.org). The purpose of this guideline is to provide information for the interpretation of HLA-B and/or CYP2C9 genotype tests so that the results can guide dosing and/or use of phenytoin. Detailed guidelines for the use of phenytoin as well as analyses of cost-effectiveness are out of scope. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines are periodically updated at http://www.pharmgkb.org.
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Affiliation(s)
- K E Caudle
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - A E Rettie
- Department of Medicinal Chemistry, University of Washington School of Pharmacy, Seattle, Washington, USA
| | - M Whirl-Carrillo
- Department of Genetics, Stanford University, Palo Alto, California, USA
| | - L H Smith
- Division of Pediatric Neurology, Department of Neurology, Indiana University, Indianapolis, Indiana, USA
| | - S Mintzer
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - M T M Lee
- 1] Laboratory for International Alliance on Genomic Research, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan [2] National Center for Genome Medicine, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [3] School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - T E Klein
- Department of Genetics, Stanford University, Palo Alto, California, USA
| | - J T Callaghan
- 1] Division of Clinical Pharmacology, Department of Medicines, Indiana University School of Medicine and Pharmacology/Toxicology, Indianapolis, Indiana, USA [2] Department of Veterans Affairs, RLR VA Medical Center, Indianapolis, Indiana, USA
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Issa AM. Clinical applications of pharmacogenomics to adverse drug reactions. Expert Rev Clin Pharmacol 2014; 1:251-60. [DOI: 10.1586/17512433.1.2.251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kaneko S, Yoshida S, Kanai K, Yasui-Furukori N, Iwasa H. Development of individualized medicine for epilepsy based on genetic information. Expert Rev Clin Pharmacol 2014; 1:661-81. [DOI: 10.1586/17512433.1.5.661] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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George M, Shewade DG, Kumar SV, Adithan C. Effect of anti-tuberculosis therapy on polymorphic drug metabolizing enzyme CYP2C9 using phenytoin as a probe drug. Indian J Pharmacol 2013; 44:485-8. [PMID: 23087510 PMCID: PMC3469952 DOI: 10.4103/0253-7613.99314] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 03/04/2012] [Accepted: 04/30/2012] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES Patients on anti-tuberculosis therapy (ATT) are more prone to drug interactions in the presence of coexisting illnesses which warrant drug therapy. Rifampicin is a strong CYP enzyme inducer while isoniazid is a potent CYP inhibitor. The objective of the study was to find the net effect of one month ATT on CYP2C9 enzyme and to correlate it with respect to the CYP2C9 genetic polymorphisms. MATERIALS AND METHODS Forty eight newly diagnosed tuberculosis patients were included in the study based on the inclusion-exclusion criteria. Before commencing ATT, they were given a single dose of phenytoin 300 mg as a probe drug for CYP2C9. Blood sample was collected after three hours to carry out CYP2C9 genotyping by PCR-RFLP method. Phenotyping for CYP2C9 enzyme was done by measuring the ratio of phenytoin and its metabolite p-HPPH (para hydroxy phenyl hydantoin) by reverse phase HPLC (high performance liquid chromatography) method before and after one month of ATT. RESULTS In the CYP2C9*1*1 genotype, the mean plasma concentrations of phenytoin before and after one month of ATT were 5.2 ± 0.3 μg/ml and 3.5 ± 0.4 μg/ml respectively, a reduction by 33% showing significant induction (P < 0.001). There was also significant decrease in the metabolic ratio after one month of ATT from 23.2 ± 4.8 to 10.1 ± 1.9 (P < 0.001). The metabolic ratio was also observed to reduce significantly (P < 0.05) when the CYP2C9*1*2, CYP2C9*1*3, and CYP2C9*3*3 data were pooled together. CONCLUSION The presence of polymorphisms in the CYP2C9 gene does not affect the induction potential of ATT.
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Affiliation(s)
- Melvin George
- Department of Pharmacology, JIPMER, Pondicherry, India
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Wilffert B, Swen J, Mulder H, Touw D, Maitland-Van der Zee AH, Deneer V. From evidence based medicine to mechanism based medicine. Reviewing the role of pharmacogenetics. Int J Clin Pharm 2013; 35:369-75. [PMID: 21049305 PMCID: PMC3651527 DOI: 10.1007/s11096-010-9446-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 10/04/2010] [Indexed: 01/11/2023]
Abstract
AIM OF THE REVIEW The translation of evidence based medicine to a specific patient presents a considerable challenge. We present by means of the examples nortriptyline, tramadol, clopidogrel, coumarins, abacavir and antipsychotics the discrepancy between available pharmacogenetic information and its implementation in daily clinical practice. METHOD Literature review. RESULTS A mechanism based approach may be helpful to personalize medicine for the individual patient to which pharmacogenetics may contribute significantly. The lack of consistency in what we accept in bioequivalence and in pharmacogenetics of drug metabolising enzymes is discussed and illustrated with the example of nortriptyline. The impact of pharmacogenetics on examples like tramadol, clopidogrel, coumarins and abacavir is described. Also the present status of the polymorphisms of 5-HT2A and C receptors in antipsychotic-induced weight gain is presented as a pharmacodynamic example with until now a greater distance to clinical implementation. CONCLUSION The contribution of pharmacogenetics to tailor-made pharmacotherapy, which especially might be of value for patients deviating from the average, has not yet reached the position it seems to deserve.
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Affiliation(s)
- Bob Wilffert
- Department of Quality and Patientsafety, Zorggroep Noorderbreedte, P.O. Box 888, 8901 BR Leeuwarden, The Netherlands.
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Samer CF, Lorenzini KI, Rollason V, Daali Y, Desmeules JA. Applications of CYP450 testing in the clinical setting. Mol Diagn Ther 2013; 17:165-84. [PMID: 23588782 PMCID: PMC3663206 DOI: 10.1007/s40291-013-0028-5] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interindividual variability in drug response is a major clinical problem. Polymedication and genetic polymorphisms modulating drug-metabolising enzyme activities (cytochromes P450, CYP) are identified sources of variability in drug responses. We present here the relevant data on the clinical impact of the major CYP polymorphisms (CYP2D6, CYP2C19 and CYP2C9) on drug therapy where genotyping and phenotyping may be considered, and the guidelines developed when available. CYP2D6 is responsible for the oxidative metabolism of up to 25% of commonly prescribed drugs such as antidepressants, antipsychotics, opioids, antiarrythmics and tamoxifen. The ultrarapid metaboliser (UM) phenotype is recognised as a cause of therapeutic inefficacy of antidepressant, whereas an increased risk of toxicity has been reported in poor metabolisers (PMs) with several psychotropics (desipramine, venlafaxine, amitriptyline, haloperidol). CYP2D6 polymorphism influences the analgesic response to prodrug opioids (codeine, tramadol and oxycodone). In PMs for CYP2D6, reduced analgesic effects have been observed, whereas in UMs cases of life-threatening toxicity have been reported with tramadol and codeine. CYP2D6 PM phenotype has been associated with an increased risk of toxicity of metoprolol, timolol, carvedilol and propafenone. Although conflicting results have been reported regarding the association between CYP2D6 genotype and tamoxifen effects, CYP2D6 genotyping may be useful in selecting adjuvant hormonal therapy in postmenopausal women. CYP2C19 is responsible for metabolising clopidogrel, proton pump inhibitors (PPIs) and some antidepressants. Carriers of CYP2C19 variant alleles exhibit a reduced capacity to produce the active metabolite of clopidogrel, and are at increased risk of adverse cardiovascular events. For PPIs, it has been shown that the mean intragastric pH values and the Helicobacter pylori eradication rates were higher in carriers of CYP2C19 variant alleles. CYP2C19 is involved in the metabolism of several antidepressants. As a result of an increased risk of adverse effects in CYP2C19 PMs, dose reductions are recommended for some agents (imipramine, sertraline). CYP2C9 is responsible for metabolising vitamin K antagonists (VKAs), non-steroidal anti-inflammatory drugs (NSAIDs), sulfonylureas, angiotensin II receptor antagonists and phenytoin. For VKAs, CYP2C9 polymorphism has been associated with lower doses, longer time to reach treatment stability and higher frequencies of supratherapeutic international normalised ratios (INRs). Prescribing algorithms are available in order to adapt dosing to genotype. Although the existing data are controversial, some studies have suggested an increased risk of NSAID-associated gastrointestinal bleeding in carriers of CYP2C9 variant alleles. A relationship between CYP2C9 polymorphisms and the pharmacokinetics of sulfonylureas and angiotensin II receptor antagonists has also been observed. The clinical impact in terms of hypoglycaemia and blood pressure was, however, modest. Finally, homozygous and heterozygous carriers of CYP2C9 variant alleles require lower doses of phenytoin to reach therapeutic plasma concentrations, and are at increased risk of toxicity. New diagnostic techniques made safer and easier should allow quicker diagnosis of metabolic variations. Genotyping and phenotyping may therefore be considered where dosing guidelines according to CYP genotype have been published, and help identify the right molecule for the right patient.
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Affiliation(s)
- C F Samer
- Clinical Pharmacology and Toxicology, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva, Switzerland.
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Hung CC, Huang HC, Gao YH, Chang WL, Ho JL, Chiou MH, Hsieh YW, Liou HH. Effects of polymorphisms in six candidate genes on phenytoin maintenance therapy in Han Chinese patients. Pharmacogenomics 2013; 13:1339-49. [PMID: 22966884 DOI: 10.2217/pgs.12.117] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AIM The present study aimed to investigate the associations between variants in pharmacokinetic- and pharmacodynamic-related genes with the dosages, concentrations and concentration-dose ratios (CDRs) of phenytoin (PHT). METHODS & RESULTS Eleven genetic polymorphisms in the six candidate genes were detected in 269 epileptic patients under maintenance PHT monotherapy by real-time PCR and PCR-RFLP. Results of a bivariate analysis demonstrated that among tested polymorphisms, carriers of the variant CYP2C9*3 tended to require significantly lower maintenance PHT dosages than wild-type carriers (p < 0.0001); on the other hand, carriers of the variants CYP2C9*3 or CYP2C19*3 revealed significantly higher CDRs than wild-type carriers (p < 0.004). In a further multivariate analysis, variants in SCN1A, CYP2C9, CYP2C19 and ABCB1 genes were significantly associated with CDRs of PHT under adjustment of age, gender and epilepsy classifications (adjusted r(2) = 20.07%). CONCLUSION The results of present study indicated that polygenic analysis may provide useful information in PHT therapy optimization.
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Affiliation(s)
- Chin-Chuan Hung
- Department of Pharmacy, College of Pharmacy, China Medical University, Taichung, Taiwan
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Castellan AC, Tod M, Gueyffier F, Audars M, Cambriels F, Kassaï B, Nony P. Quantitative Prediction of the Impact of Drug Interactions and Genetic Polymorphisms on Cytochrome P450 2C9 Substrate Exposure. Clin Pharmacokinet 2013; 52:199-209. [DOI: 10.1007/s40262-013-0031-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Goutelle S, Bourguignon L, Bleyzac N, Berry J, Clavel-Grabit F, Tod M. In vivo quantitative prediction of the effect of gene polymorphisms and drug interactions on drug exposure for CYP2C19 substrates. AAPS JOURNAL 2013; 15:415-26. [PMID: 23319287 DOI: 10.1208/s12248-012-9431-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/20/2012] [Indexed: 12/17/2022]
Abstract
We present a unified quantitative approach to predict the in vivo alteration in drug exposure caused by either cytochrome P450 (CYP) gene polymorphisms or CYP-mediated drug-drug interactions (DDI). An application to drugs metabolized by CYP2C19 is presented. The metrics used is the ratio of altered drug area under the curve (AUC) to the AUC in extensive metabolizers with no mutation or no interaction. Data from 42 pharmacokinetic studies performed in CYP2C19 genetic subgroups and 18 DDI studies were used to estimate model parameters and predicted AUC ratios by using Bayesian approach. Pharmacogenetic information was used to estimate a parameter of the model which was then used to predict DDI. The method adequately predicted the AUC ratios published in the literature, with mean errors of -0.15 and -0.62 and mean absolute errors of 0.62 and 1.05 for genotype and DDI data, respectively. The approach provides quantitative prediction of the effect of five genotype variants and 10 inhibitors on the exposure to 25 CYP2C19 substrates, including a number of unobserved cases. A quantitative approach for predicting the effect of gene polymorphisms and drug interactions on drug exposure has been successfully applied for CYP2C19 substrates. This study shows that pharmacogenetic information can be used to predict DDI. This may have important implications for the development of personalized medicine and drug development.
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Affiliation(s)
- Sylvain Goutelle
- Service Pharmaceutique, Groupement Hospitalier de Gériatrie, Hospices Civils de Lyon, Lyon, France.
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The role of CYP2C9 polymorphisms in phenytoin-related cerebellar atrophy. Seizure 2013; 22:194-7. [PMID: 23298603 DOI: 10.1016/j.seizure.2012.12.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Phenytoin is known to be able to induce cerebellar atrophy in patients with epilepsy. It is also known that a CYP2C9 mutation (*2 or *3) reduces phenytoin metabolism by 25-50% and can increase the risk of phenytoin-related side effects. We examined the influence of CYP2C9 polymorphisms on total cerebellar volume and cerebellar gray and white matter volumes in patients with epilepsy taking phenytoin. METHODS For the genotyping, 100 adult patients with documented epilepsy who had been taking phenytoin for >1 year were selected. From this group, we randomly selected 19 mutant individuals (MT group; CYP2C9*2 and *3) for a whole-brain volume measurement using MRI and 19 wild-type individuals (group WT; CYP2C9*1) with similar clinical and demographic characteristics to those in the MT group for comparison. Total intracranial volume measurements were used to normalize the acquired volumes, which were separated into gray matter volume, white matter volume, and total volume. RESULTS The MT group exhibited a significant reduction in cerebellar white matter volume (p=0.002) but not in total cerebellar volume. CONCLUSION Our study is the first to report evidence linking CYP2C9 polymorphism and a reduction in cerebellar volume in epileptic users of phenytoin.
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López M, Dorado P, Monroy N, Alonso ME, Jung-Cook H, Machín E, Peñas-Lledó E, Llerena A. Pharmacogenetics of the antiepileptic drugs phenytoin and lamotrigine. ACTA ACUST UNITED AC 2012; 26:5-12. [PMID: 21557672 DOI: 10.1515/dmdi.2011.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Patients treated with antiepileptic drugs can exhibit large interindividual variability in clinical efficacy or adverse effects. This could be partially due to genetic variants in genes coding for proteins that function as drug metabolizing enzymes, drug transporters or drug targets. The purpose of this article is to provide an overview of the current knowledge on the pharmacogenetics of two commonly prescribed antiepileptic drugs with similar mechanisms of action; phenytoin (PHT) and lamotrigine (LTG). These two drugs have been selected in order to model the pharmacogenetics of Phase I and Phase II metabolism for PHT and LTG, respectively. In light of the present evidence, patients treated with PHT could benefit from CYP2C9 and CYP2C19 genotyping/phenotyping. For those under treatment with LTG, UGT1A4 and UGT2B7 genotyping might be of clinical use and could contribute to the interindividual variability in LTG concentration to dose ratio in epileptic patients.
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Affiliation(s)
- Marisol López
- Department of Biological Systems, Universidad Autónoma Metropolitana-Xochimilco, Mexico City, Mexico
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Therapeutic Drug Monitoring of Classical and Newer Anticonvulsants. Ther Drug Monit 2012. [DOI: 10.1016/b978-0-12-385467-4.00012-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Cavalleri GL, Delanty N. Opportunities and challenges for genome sequencing in the clinic. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012; 89:65-83. [PMID: 23046882 DOI: 10.1016/b978-0-12-394287-6.00003-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human genome sequencing technology is developing rapidly. These developments are providing exciting opportunities for genetic mapping of human traits, ranging from accelerated discovery of mutations underlying relatively simple Mendelian disorders to more genetically complex human diseases. This chapter outlines the development of whole-genome sequencing in a historical context of genetic mapping and explores the impact that sequencing is having on gene discovery study design. Using the example of epilepsy, the authors outline the opportunities and barriers for the translation of genetic predictors from discovery to the clinic. Finally, the authors discuss the practical challenges of actual implementation of whole-genome sequencing to the clinic.
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Affiliation(s)
- Gianpiero L Cavalleri
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland.
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Twardowschy CA, Werneck LC, Scola RH, De Paola L, Silvado CE. CYP2C9 polymorphism in patients with epilepsy: genotypic frequency analyzes and phenytoin adverse reactions correlation. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:153-8. [PMID: 21537551 DOI: 10.1590/s0004-282x2011000200002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 11/08/2010] [Indexed: 11/22/2022]
Abstract
OBJECTIVE CYP2C9 is a major enzyme in human drug metabolism and the polymorphism observed in the corresponding gene may affect therapeutic outcome during treatment. The distribution of variant CYP2C9 alleles and prevalence of phenytoin adverse reactions were hereby investigated in a population of patients diagnosed with epilepsy. METHOD Allele-specific PCR analysis was carried out in order to determine frequencies of the two most common variant alleles, CYP2C9*2 and CYP2C9*3 in genomic DNA isolated from 100 epileptic patients. We also analyzed the frequency of phenytoin adverse reactions among those different genotypes groups. The data was presented as mean±standard deviation. RESULTS The mean age at enrollment was 39.6±10.3 years (range, 17-72 years) and duration of epilepsy was 26.5±11.9 years (range 3-48 years). The mean age at epilepsy onset was 13.1±12.4 years (range, 1 month-62 years). Frequencies of CYP2C9*1 (84%), CYP2C9*2 (9%) and CYP2C9*3 (7%) were similar to other published reports. Phenytoin adverse reactions were usually mild and occurred in 15% patients, without correlation with the CYP2C9 polymorphism (p=0.34). CONCLUSION Our findings indicate an overall similar distribution of the CYP2C9 alleles in a population of patients diagnosed with epilepsy in the South of Brazil, compared to other samples. This sample of phenytoin users showed no drug related adverse reactions and CYP2C9 allele type correlation. The role of CYP2C9 polymorphism influence on phenytoin adverse reaction remains to be determined since some literature evidence and our data found negative results.
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Cavalleri GL, McCormack M, Alhusaini S, Chaila E, Delanty N. Pharmacogenomics and epilepsy: the road ahead. Pharmacogenomics 2011; 12:1429-47. [DOI: 10.2217/pgs.11.85] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Epilepsy is one of the most common, serious neurological disorders, affecting an estimated 50 million people worldwide. The condition is typically treated using antiepileptic drugs of which there are 16 in widespread use. However, there are many different syndrome and seizure types within epilepsy and information guiding clinicians on the most effective drug and dose for individual patients is lacking. Further, all of the antiepileptic drugs have associated adverse reactions, some of which are severe and life-threatening. Here, we review the pharmacogenomic work to date in the context of these issues and comment on key aspects of study design that are required to speed up the identification of clinically relevant genetic factors.
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Affiliation(s)
| | - Mark McCormack
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Saud Alhusaini
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Elijah Chaila
- The Division of Neurology, Beaumont Hospital, Dublin, Ireland
| | - Norman Delanty
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
- The Division of Neurology, Beaumont Hospital, Dublin, Ireland
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Kumari R, Lakhan R, Garg RK, Kalita J, Misra UK, Mittal B. Pharmacogenomic association study on the role of drug metabolizing, drug transporters and drug target gene polymorphisms in drug-resistant epilepsy in a north Indian population. INDIAN JOURNAL OF HUMAN GENETICS 2011; 17 Suppl 1:S32-40. [PMID: 21747585 PMCID: PMC3125053 DOI: 10.4103/0971-6866.80357] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND: In epilepsy, in spite of the best possible medications and treatment protocols, approximately one-third of the patients do not respond adequately to anti-epileptic drugs. Such interindividual variations in drug response are believed to result from genetic variations in candidate genes belonging to multiple pathways. MATERIALS AND METHODS: In the present pharmacogenetic analysis, a total of 402 epilepsy patients were enrolled. Of them, 128 were diagnosed as multiple drug-resistant epilepsy and 274 patients were diagnosed as having drug-responsive epilepsy. We selected a total of 10 candidate gene polymorphisms belonging to three major classes, namely drug transporters, drug metabolizers and drug targets. These genetic polymorphism included CYP2C9 c.430C>T (*2 variant), CYP2C9 c.1075 A>C (*3 variant), ABCB1 c.3435C>T, ABCB1c.1236C>T, ABCB1c.2677G>T/A, SCN1A c.3184 A> G, SCN2A c.56G>A (p.R19K), GABRA1c.IVS11 + 15 A>G and GABRG2 c.588C>T. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods, and each genotype was confirmed via direct DNA sequencing. The relationship between various genetic polymorphisms and responsiveness was examined using binary logistic regression by SPSS statistical analysis software. RESULTS: CYP2C9 c.1075 A>C polymorphism showed a marginal significant difference between drug resistance and drug-responsive patients for the AC genotype (Odds ratio [OR] = 0.57, 95% confidence interval [CI] = 0.32–1.00; P = 0.05). In drug transporter, ABCB1c.2677G>T/A polymorphism, allele A was associated with drug-resistant phenotype in epilepsy patients (P = 0.03, OR = 0.31, 95% CI = 0.10-0.93). Similarly, the variant allele frequency of SCN2A c.56 G>A single nucleotide polymorphism was significantly higher in drug-resistant patients (P = 0.03; OR = 1.62, 95% CI = 1.03, 2.56). We also observed a significant difference at the genotype as well as allele frequencies of GABRA1c.IVS11 + 15 A > G polymorphism in drug-resistant patients for homozygous GG genotype (P = 0.03, OR = 1.84, 95% CI = 1.05–3.23) and G allele (P = 0.02, OR = 1.43, 95% CI = 1.05–1.95). CONCLUSIONS: Our results showed that pharmacogenetic variants have important roles in epilepsy at different levels. It may be noted that multi-factorial diseases like epilepsy are also regulated by various other factors that may also be considered in the future.
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Affiliation(s)
- Ritu Kumari
- Department of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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Antoniou T, Gomes T, Mamdani MM, Juurlink DN. Trimethoprim/sulfamethoxazole-induced phenytoin toxicity in the elderly: a population-based study. Br J Clin Pharmacol 2011; 71:544-9. [PMID: 21395647 DOI: 10.1111/j.1365-2125.2010.03866.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
AIMS Pharmacokinetic studies suggest that trimethoprim (TMP) can inhibit the hepatic metabolism of phenytoin, but the clinical relevance of this is uncertain. We studied the risk of phenytoin toxicity following the prescription of trimethoprim/sulfamethoxazole (TMP/SMX), a commonly used antibiotic, among elderly patients receiving phenytoin. METHODS We conducted a population-based, nested case-control study of a cohort of Ontario residents aged 66 years of age or older treated with phenytoin over a 17-year period (April 1 1992 to March 31 2009). Within this group, case patients were those hospitalized with phenytoin toxicity. For each case, we identified up to four control patients from the same cohort, matched for age and sex, and determined the odds ratio (OR) for the association between phenytoin toxicity and receipt of TMP/SMX in the preceding 30 days. RESULTS Among 58 429 elderly patients receiving phenytoin during the study period, we identified 796 case patients hospitalized for phenytoin toxicity and 3148 matched controls. Following multivariable adjustment for potential confounders, we observed a more than doubling of the risk of phenytoin toxicity following the receipt of TMP/SMX [adjusted OR 2.11, 95% confidence interval (CI) 1.24, 3.60]. In contrast, we observed no such risk with amoxicillin, an antibiotic with similar indications but not expected to interact with phenytoin (adjusted OR 1.12, 95% CI 0.64, 1.98). CONCLUSION Among older patients receiving phenytoin, treatment with TMP/SMX is associated with a more than twofold increase in the risk of phenytoin toxicity. When clinically appropriate, alternate antibiotics should be considered for these patients.
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Affiliation(s)
- Tony Antoniou
- University of Toronto, Toronto, Department of Family and Community Medicine, St. Michael's Hospital, Toronto, Ontario, Canada.
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