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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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Zhao W, Meng H. Effects of genetic polymorphism of drug-metabolizing enzymes on the plasma concentrations of antiepileptic drugs in Chinese population. Bioengineered 2022; 13:7709-7745. [PMID: 35290166 PMCID: PMC9278974 DOI: 10.1080/21655979.2022.2036916] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/02/2022] Open
Abstract
As a chronic brain disease, epilepsy affects ~50 million people worldwide. The traditional antiepileptic drugs (AEDs) are widely applied but showing various problems. Although the new AEDs have partially solved the problems of traditional AEDs, the current clinical application of traditional AEDs are not completely replaced by new drugs, particularly due to the large individual differences in drug plasma concentrations and narrow therapeutic windows among patients. Therefore, it is still clinically important to continue to treat patients using traditional AEDs with individualized therapeutic plans. To date, our understanding of the molecular and genetic mechanisms regulating plasma concentrations of AEDs has advanced rapidly, expanding the knowledge on the effects of genetic polymorphisms of genes encoding drug-metabolizing enzymes on the plasma concentrations of AEDs. It is increasingly imperative to summarize and conceptualize the clinical significance of recent studies on individualized therapeutic regimens. In this review, we extensively summarize the critical effects of genetic polymorphisms of genes encoding drug-metabolizing enzymes on the plasma concentrations of several commonly used AEDs as well as the clinical significance of testing genotypes related to drug metabolism on individualized drug dosage. Our review provides solid experimental evidence and clinical guidance for the therapeutic applications of these AEDs.
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Affiliation(s)
- Weixuan Zhao
- Department of Neurology, the First Hospital of Jilin University, Jilin University, Changchun, China
| | - Hongmei Meng
- Department of Neurology, the First Hospital of Jilin University, Jilin University, Changchun, China
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Bothos E, Ntoumou E, Kelaidoni K, Roukas D, Drakoulis N, Papasavva M, Karakostis FA, Moulos P, Karakostis K. Clinical pharmacogenomics in action: design, assessment and implementation of a novel pharmacogenetic panel supporting drug selection for diseases of the central nervous system (CNS). J Transl Med 2021; 19:151. [PMID: 33858454 PMCID: PMC8048316 DOI: 10.1186/s12967-021-02816-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/02/2021] [Indexed: 12/18/2022] Open
Abstract
Background Pharmacogenomics describes the link between gene variations (polymorphisms) and drug responses. In view of the implementation of precision medicine in personalized healthcare, pharmacogenetic tests have recently been introduced in the clinical practice. However, the translational aspects of such tests have been limited due to the lack of robust population-based evidence. Materials In this paper we present a novel pharmacogenetic panel (iDNA Genomics-PGx–CNS or PGx–CNS), consisting of 24 single nucleotide polymorphisms (SNPs) on 13 genes involved in the signaling or/and the metabolism of 28 approved drugs currently administered to treat diseases of the Central Nervous System (CNS). We have tested the PGx–CNS panel on 501 patient-derived DNA samples from a southeastern European population and applied biostatistical analyses on the pharmacogenetic associations involving drug selection, dosing and the risk of adverse drug events (ADEs). Results Results reveal the occurrences of each SNP in the sample and a strong correlation with the European population. Nonlinear principal component analysis strongly indicates co-occurrences of certain variants. The metabolization efficiency (poor, intermediate, extensive, ultra-rapid) and the frequency of clinical useful pharmacogenetic, associations in the population (drug relevance), are also described, along with four exemplar clinical cases illustrating the strong potential of the PGx–CNS panel, as a companion diagnostic assay. It is noted that pharmacogenetic associations involving copy number variations (CNVs) or the HLA gene were not included in this analysis. Conclusions Overall, results illustrate that the PGx–CNS panel is a valuable tool supporting therapeutic medical decisions, urging its broad clinical implementation. Supplementary Information The online version contains supplementary material available at 10.1186/s12967-021-02816-3.
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Affiliation(s)
- E Bothos
- HybridStat Predictive Analytics, Athens, Greece.,Institute of Communications and Computer Systems, National Technical University of Athens, Athens, Greece
| | - E Ntoumou
- iDNA Genomics Private Company, Evrota 25, Kifissia, 145 64, Athens, Greece
| | - K Kelaidoni
- iDNA Genomics Private Company, Evrota 25, Kifissia, 145 64, Athens, Greece
| | - D Roukas
- Department of Psychiatry, Army Hospital (NIMTS), 417 Veterans, 115 21, Athens, Greece
| | - N Drakoulis
- Research Group of Clinical Pharmacology and Pharmacogenomics, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Zografou, Greece
| | - M Papasavva
- Research Group of Clinical Pharmacology and Pharmacogenomics, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Zografou, Greece
| | - F A Karakostis
- Paleoanthropology, Senckenberg Centre for Human Evolution and Palaeoenvironment, Department of Geosciences, University of Tübingen, Tübingen, Germany
| | - P Moulos
- HybridStat Predictive Analytics, Athens, Greece.,Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center 'Alexander Fleming', 34 Fleming str, 16672, Athens, Vari, Greece
| | - K Karakostis
- iDNA Genomics Private Company, Evrota 25, Kifissia, 145 64, Athens, Greece.
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Jomura R, Akanuma SI, Bauer B, Yoshida Y, Kubo Y, Hosoya KI. Participation of Monocarboxylate Transporter 8, But Not P-Glycoprotein, in Carrier-Mediated Cerebral Elimination of Phenytoin across the Blood-Brain Barrier. Pharm Res 2021; 38:113-125. [PMID: 33527223 DOI: 10.1007/s11095-021-03003-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 12/09/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE In this study, we investigated in detail the transport of phenytoin across the blood-brain barrier (BBB) to identify the transporter(s) involved in BBB-mediated phenytoin efflux from the brain. METHODS We evaluated the brain-to-blood efflux transport of phenytoin in vivo by determining the brain efflux index (BEI) and uptake in brain slices. We additionally conducted brain perfusion experiments and BEI studies in P-glycoprotein (P-gp)-deficient mice. In addition, we determined the mRNA expression of monocarboxylate transporter (MCT) in isolated brain capillaries and performed phenytoin uptake studies in MCT-expressing Xenopus oocytes. RESULTS [14C]Phenytoin brain efflux was time-dependent with a half-life of 17 min in rats and 31 min in mice. Intracerebral pre-administration of unlabeled phenytoin attenuated BBB-mediated phenytoin efflux transport, suggesting carrier-mediated phenytoin efflux transport across the BBB. Pre-administration of P-gp substrates in rats and genetic P-gp deficiency in mice did not affect BBB-mediated phenytoin efflux transport. In contrast, pre-administration of MCT8 inhibitors attenuated phenytoin efflux. Moreover, rat MCT8-expressing Xenopus oocytes exhibited [14C]phenytoin uptake, which was inhibited by unlabeled phenytoin. CONCLUSION Our data suggest that MCT8 at the BBB participates in phenytoin efflux transport from the brain to the blood.
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Affiliation(s)
- Ryuta Jomura
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Shin-Ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan. .,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 800 S Limestone, Lexington, Kentucky, 40536-0230, USA.
| | - Björn Bauer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 800 S Limestone, Lexington, Kentucky, 40536-0230, USA
| | - Yukiko Yoshida
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Ken-Ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
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Nizamuddin S, Dubey S, Singh S, Sharma S, Machha P, Thangaraj K. CYP2C9 Variations and Their Pharmacogenetic Implications Among Diverse South Asian Populations. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2021; 14:135-147. [PMID: 33536773 PMCID: PMC7850565 DOI: 10.2147/pgpm.s272015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/01/2020] [Indexed: 11/23/2022]
Abstract
Introduction Allelic frequency distribution of drug metabolizing enzyme genes among populations is important to identify risk groups for adverse drug reaction and to select representative populations for clinical trials. Although India emerged as an important hub for clinical trials, information about the pharmacogenetic diversity for this region is still lacking. Here, we investigated genetic diversity of cytochrome-P450-2C9 (CYP2C9) gene which metabolizes wide range of drugs and is highly expressed in the human liver. Methods In total, 1278 individuals from 36 diverse Indian populations, 210 individuals from in-house data-repository and 489 other South Asian samples from the 1000 Genomes Project were selected. Variants observed in CYP2C9 gene were subjected to various statistical analyses. Results High frequency of CYP2C9*3 (~13%) and CYP2C9*3/*3 (~1%) was observed among South Asians, compared to 21 populations living outside the Indian subcontinent. The allelic/genotypic frequency does not correlate with geographical location or linguistic affiliation, except populations speaking Tibeto-Burmans language, who have lower frequency of CYP2C9*3 and CYP2C9*3/*3. Since, South Asians practice strict endogamy, presence of unique mutation and high frequency of homozygous genotypes not surprising. CYP2C9*3 has been associated with therapeutic response.The effect of CYP2C9*3/*3 is more pronounced compared to heterozygous and wild type homozygous genotypes as evident in many in vitro studies. As South Asians have high frequency, it would be interesting to explore potential of CYP2C9*3 as a marker for personalized therapy. Our study revealed several rare functional variants, which form eight novel and rare haplotypes of CYP2C9 (CYP2C9*63–*70). Of which, CYP2C9*64, *65, *66, *68, *69 and *70 haplotypes are South Asian-specific. Conclusion Overall, we find high genetic heterogeneity within South Asians and identified South Asian-specific putative functional CYP2C9 haplotypes. High frequency of CYP2C9*3 and CYP2C9*3/*3 was observed in South Asian populations. Taken together, current study greatly enriches the knowledge of naturally occurring CYP2C9 variants and its diversity in South Asia, which are relevant to further CYP2C9-related functional research and for personalized medicine.
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Affiliation(s)
- Sheikh Nizamuddin
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India.,German Cancer Consortium (DKTK) c/o Zentrale Klinische Forschung (ZKF), University Medical Center, Freiburg, Germany
| | - Shivendra Dubey
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Sakshi Singh
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Saurav Sharma
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Pratheusa Machha
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India.,AcSIR (Academy of Scientific and Innovative Research), CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India.,AcSIR (Academy of Scientific and Innovative Research), CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India.,DBT-Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
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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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Anseeuw K, Mowry JB, Burdmann EA, Ghannoum M, Hoffman RS, Gosselin S, Lavergne V, Nolin TD. Extracorporeal Treatment in Phenytoin Poisoning: Systematic Review and Recommendations from the EXTRIP (Extracorporeal Treatments in Poisoning) Workgroup. Am J Kidney Dis 2015; 67:187-97. [PMID: 26578149 DOI: 10.1053/j.ajkd.2015.08.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 08/28/2015] [Indexed: 01/12/2023]
Abstract
The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup conducted a systematic literature review using a standardized process to develop evidence-based recommendations on the use of extracorporeal treatment (ECTR) in patients with phenytoin poisoning. The authors reviewed all articles, extracted data, summarized findings, and proposed structured voting statements following a predetermined format. A 2-round modified Delphi method was used to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. 51 articles met the inclusion criteria. Only case reports, case series, and pharmacokinetic studies were identified, yielding a very low quality of evidence. Clinical data from 31 patients and toxicokinetic grading from 46 patients were abstracted. The workgroup concluded that phenytoin is moderately dialyzable (level of evidence = C) despite its high protein binding and made the following recommendations. ECTR would be reasonable in select cases of severe phenytoin poisoning (neutral recommendation, 3D). ECTR is suggested if prolonged coma is present or expected (graded 2D) and it would be reasonable if prolonged incapacitating ataxia is present or expected (graded 3D). If ECTR is used, it should be discontinued when clinical improvement is apparent (graded 1D). The preferred ECTR modality in phenytoin poisoning is intermittent hemodialysis (graded 1D), but hemoperfusion is an acceptable alternative if hemodialysis is not available (graded 1D). In summary, phenytoin appears to be amenable to extracorporeal removal. However, because of the low incidence of irreversible tissue injury or death related to phenytoin poisoning and the relatively limited effect of ECTR on phenytoin removal, the workgroup proposed the use of ECTR only in very select patients with severe phenytoin poisoning.
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Affiliation(s)
- Kurt Anseeuw
- Campus Stuivenberg, Emergency Medicine, Antwerpen, Belgium
| | - James B Mowry
- Indiana University Health, Indiana Poison Center, Indianapolis, IN
| | - Emmanuel A Burdmann
- LIM 12, Division of Nephrology, University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Marc Ghannoum
- Department of Nephrology, Verdun Hospital, University of Montreal, Verdun, QC, Canada
| | - Robert S Hoffman
- Division of Medical Toxicology, Ronald O. Perelman Department of Emergency Medicine, New York University School of Medicine, New York, NY
| | - Sophie Gosselin
- Department of Emergency Medicine, Medical Toxicology Division, McGill University Health Centre & Department of Medicine, McGill University, Montreal, QC, Canada
| | - Valery Lavergne
- Department of Medical Biology, Sacre-Coeur Hospital, University of Montreal, Montreal, QC, Canada
| | - Thomas D Nolin
- Department of Pharmacy and Therapeutics, University of Pittsburgh Schools of Pharmacy and Medicine, Pittsburgh, PA; Renal Electrolyte Division, Department of Medicine, University of Pittsburgh Schools of Pharmacy and Medicine, Pittsburgh, PA.
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PharmGKB summary: very important pharmacogene information for human leukocyte antigen B. Pharmacogenet Genomics 2015; 25:205-21. [PMID: 25647431 DOI: 10.1097/fpc.0000000000000118] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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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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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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Varshney E, Saha N, Tandon M, Shrivastava V, Ali S. Genotype-phenotype correlation of cytochrome P450 2C9 polymorphism in Indian National Capital Region. Eur J Drug Metab Pharmacokinet 2013; 38:275-82. [PMID: 23446815 DOI: 10.1007/s13318-013-0124-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 02/13/2013] [Indexed: 01/31/2023]
Abstract
Identification of polymorphism of cytochrome P450 2C9 (CYP2C9) enzymes in different ethnic populations is important to understand the differences in clinical responses to drugs. This study determines the CYP2C9 genetic polymorphism in Indian National Capital Region and correlates the phenotype-genotype. Losartan (25 mg) was administered to 107 volunteers to assess CYP2C9 activity, and, on the basis of results, volunteers were categorized as rapid and poor metabolizers. Molecular typing of CYP2C9*1 (wild type), CYP2C9*2, and CYP2C9*3 (the most common variant) was carried out by single-base primer extension technology for 37 subjects, of which 9 were poor metabolizers, and 28 were rapid metabolizers. 14.28 % of the studied population was identified as poor metabolizer for the category of drugs metabolized by CYP2C9. Significant difference was observed between the mean ratio (drug/metabolite) of poor (11.38 ± 5.88) and rapid (1.18 ± 1.11) drug metabolizers. The study suggests that phenotyping of CYP2C9 is desirable before enrollment of subjects for clinical trials or for deciding drug dose regimen as 14.28 % of study population was found to be poor metabolizer for the category of drugs metabolized by CYP2C9. This study establishes phenotype-genotype correlation, and proposes to use genotyping or phenotyping to evaluate the status of drug metabolizing capacity of CYP2C9 as a primary screening procedure before enrolling subjects in clinical trials or in clinical practice.
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Affiliation(s)
- Ekta Varshney
- Department of Biochemistry, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi, 110062, India
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