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Influence of cytochrome P450 2D6 polymorphism on hippocampal white matter and treatment response in schizophrenia. NPJ SCHIZOPHRENIA 2021; 7:5. [PMID: 33514751 PMCID: PMC7846743 DOI: 10.1038/s41537-020-00134-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/12/2020] [Indexed: 12/16/2022]
Abstract
Cytochrome P450 2D6 (CYP2D6) is expressed at high levels in the brain and plays a considerable role in the biotransformation and neurotransmission of dopamine. This raises the question of whether CYP2D6 variations and its impact on the brain can confer susceptibility to schizophrenia. We investigated the possible links among the CYP2D6 genotype, white matter (WM) integrity of the hippocampus, and the treatment response to antipsychotic drugs in Korean patients with schizophrenia (n = 106). Brain magnetic resonance imaging and genotyping for CYP2D6 were conducted at baseline. The severity of clinical symptoms and the treatment response were assessed using the Positive and Negative Syndrome Scale (PANSS). After genotyping, 43 participants were classified as intermediate metabolizers (IM), and the remainder (n = 63) were classified as extensive metabolizers (EM). IM participants showed significantly higher fractional anisotropy (FA) values in the right hippocampus compared to EM participants. Radial diffusivity (RD) values were significantly lower in the overlapping region of the right hippocampus in the IM group than in the EM group. After 4 weeks of antipsychotic treatment, the EM group showed more improvements in positive symptoms than the IM group. FAs and RDs in the CYP2D6-associated hippocampal WM region were significantly correlated with a reduction in the positive symptom subscale of the PANSS. Greater improvements in positive symptoms were negatively associated with FAs, and positively associated with RDs in the right hippocampal region. The findings suggest that CYP26D-associated hippocampal WM alterations could be a possible endophenotype for schizophrenia that accounts for individual differences in clinical features and treatment responses.
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Nichols AI, Liao S, Abbas R. Population Pharmacokinetics of Desvenlafaxine: Pharmacokinetics in Korean Versus US Populations. Clin Pharmacol Drug Dev 2017; 7:441-450. [DOI: 10.1002/cpdd.419] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/30/2017] [Indexed: 11/11/2022]
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Ryu S, Park S, Lee JH, Kim YR, Na HS, Lim HS, Choi HY, Hwang IY, Lee JG, Park ZW, Oh WY, Kim JM, Choi SE. A Study on CYP2C19 and CYP2D6 Polymorphic Effects on Pharmacokinetics and Pharmacodynamics of Amitriptyline in Healthy Koreans. Clin Transl Sci 2017; 10:93-101. [PMID: 28296334 PMCID: PMC5355968 DOI: 10.1111/cts.12451] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
We performed a double-blinded, genotype-based stratification study to explore the pharmacokinetics and pharmacodynamics of amitriptyline according to CYP2C19 and CYP2D6 genotype in Korean subjects. Twenty-four healthy adults were grouped by genotype of CYP2C19 and CYP2D6. After a single dose of 25 mg of amitriptyline, blood samples were collected and anticholinergic effects were measured. The extent of N-demethylation of amitriptyline significantly decreased in subjects carrying two nonfunctional alleles of CYP2C19. The extent of hydroxylation of amitriptyline or nortriptyline was significantly reduced in subjects carrying two CYP2D6 decreased functional alleles compared with those with no or one decreased functional allele. The overall metabolic pathway of amitriptyline was more likely to be dominated by CYP2C19 than CYP2D6. The gene variations of CYP2C19 and CYP2D6 did not change the pharmacodynamic effect. The findings of this study will provide useful information on individualized drug treatment with amitriptyline considering both CYP2D6 and CYP2C19 gene variations.
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Affiliation(s)
- S Ryu
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - S Park
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - J H Lee
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - Y R Kim
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - H S Na
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - H S Lim
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, University of Ulsan, Asan Medical Center, Republic of Korea
| | - H Y Choi
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, University of Ulsan, Asan Medical Center, Republic of Korea
| | - I Y Hwang
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - J G Lee
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - Z W Park
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - W Y Oh
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - J M Kim
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
| | - S E Choi
- Clinical Research Division, National Institute of Food and Drug Safety, Ministry of Food and Drug Safety, Republic of Korea
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Ahmed S, Zhou Z, Zhou J, Chen SQ. Pharmacogenomics of Drug Metabolizing Enzymes and Transporters: Relevance to Precision Medicine. GENOMICS PROTEOMICS & BIOINFORMATICS 2016; 14:298-313. [PMID: 27729266 PMCID: PMC5093856 DOI: 10.1016/j.gpb.2016.03.008] [Citation(s) in RCA: 152] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/17/2016] [Accepted: 03/08/2016] [Indexed: 01/11/2023]
Abstract
The interindividual genetic variations in drug metabolizing enzymes and transporters influence the efficacy and toxicity of numerous drugs. As a fundamental element in precision medicine, pharmacogenomics, the study of responses of individuals to medication based on their genomic information, enables the evaluation of some specific genetic variants responsible for an individual’s particular drug response. In this article, we review the contributions of genetic polymorphisms to major individual variations in drug pharmacotherapy, focusing specifically on the pharmacogenomics of phase-I drug metabolizing enzymes and transporters. Substantial frequency differences in key variants of drug metabolizing enzymes and transporters, as well as their possible functional consequences, have also been discussed across geographic regions. The current effort illustrates the common presence of variability in drug responses among individuals and across all geographic regions. This information will aid health-care professionals in prescribing the most appropriate treatment aimed at achieving the best possible beneficial outcomes while avoiding unwanted effects for a particular patient.
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Affiliation(s)
- Shabbir Ahmed
- Department of Precision Medicine and Biopharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhan Zhou
- Department of Precision Medicine and Biopharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jie Zhou
- Department of Precision Medicine and Biopharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shu-Qing Chen
- Department of Precision Medicine and Biopharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China; International Center for Precision Medicine, Zhejiang California International NanoSystems Institute, Hangzhou 310058, China.
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Claudio-Campos K, Orengo-Mercado C, Renta JY, Peguero M, García R, Hernández G, Corey S, Cadilla CL, Duconge J. Pharmacogenetics of healthy volunteers in Puerto Rico. Drug Metab Pers Ther 2016; 30:239-49. [PMID: 26501165 DOI: 10.1515/dmpt-2015-0021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/24/2015] [Indexed: 12/23/2022]
Abstract
Puerto Ricans are a unique Hispanic population with European, Native American (Taino), and higher West African ancestral contributions than other non-Caribbean Hispanics. In admixed populations, such as Puerto Ricans, genetic variants can be found at different frequencies when compared to parental populations and uniquely combined and distributed. Therefore, in this review, we aimed to collect data from studies conducted in healthy Puerto Ricans and to report the frequencies of genetic polymorphisms with major relevance in drug response. Filtering for healthy volunteers or individuals, we performed a search of pharmacogenetic studies in academic literature databases without limiting the period of the results. The search was limited to Puerto Ricans living in the island, excluding those studies performed in mainland (United States). We found that the genetic markers impacting pharmacological therapy in the areas of cardiovascular, oncology, and neurology are the most frequently investigated. Coincidently, the top causes of mortality in the island are cardiovascular diseases, cancer, diabetes, Alzheimer's disease, and stroke. In addition, polymorphisms in genes that encode for members of the CYP450 family (CYP2C9, CYP2C19, and CYP2D6) are also available due to their relevance in the metabolism of drugs. The complex genetic background of Puerto Ricans is responsible for the divergence in the reported allele frequencies when compared to parental populations (Africans, East Asians, and Europeans). The importance of reporting the findings of pharmacogenetic studies conducted in Puerto Ricans is to identify genetic variants with potential utility among this genetically complex population and eventually move forward the adoption of personalized medicine in the island.
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Interethnic variation of CYP2C19 alleles, 'predicted' phenotypes and 'measured' metabolic phenotypes across world populations. THE PHARMACOGENOMICS JOURNAL 2015; 16:113-23. [PMID: 26503820 DOI: 10.1038/tpj.2015.70] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/15/2015] [Accepted: 08/19/2015] [Indexed: 02/08/2023]
Abstract
The present study evaluates the worldwide frequency distribution of CYP2C19 alleles and CYP2C19 metabolic phenotypes ('predicted' from genotypes and 'measured' with a probe drug) among healthy volunteers from different ethnic groups and geographic regions, as well as the relationship between the 'predicted' and 'measured' CYP2C19 metabolic phenotypes. A total of 52 181 healthy volunteers were studied within 138 selected original research papers. CYP2C19*17 was 42- and 24-fold more frequent in Mediterranean-South Europeans and Middle Easterns than in East Asians (P<0.001, in both cases). Contrarily, CYP2C19*2 and CYP2C19*3 alleles were more frequent in East Asians (30.26% and 6.89%, respectively), and even a twofold higher frequency of these alleles was found in Native populations from Oceania (61.30% and 14.42%, respectively; P<0.001, in all cases), which may be a consequence of genetic drift process in the Pacific Islands. Regarding CYP2C19 metabolic phenotype, poor metabolizers (PMs) were more frequent among Asians than in Europeans, contrarily to the phenomenon reported for CYP2D6. A correlation has been found between the frequencies of CYP2C19 poor metabolism 'predicted' from CYP2C19 genotypes (gPMs) and the poor metabolic phenotype 'measured' with a probe drug (mPMs) when subjects are either classified by ethnicity (r=0.94, P<0.001) or geographic region (r=0.99, P=0.002). Nevertheless, further research is needed in African and Asian populations, which are under-represented, and additional CYP2C19 variants and the 'measured' phenotype should be studied.
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LLerena A, Naranjo MEG, Rodrigues-Soares F, Penas-LLedó EM, Fariñas H, Tarazona-Santos E. Interethnic variability ofCYP2D6alleles and of predicted and measured metabolic phenotypes across world populations. Expert Opin Drug Metab Toxicol 2014; 10:1569-83. [DOI: 10.1517/17425255.2014.964204] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Brennan BJ, Xu ZX, Grippo JF. Effect of peginterferon alfa-2a (40KD) on cytochrome P450 isoenzyme activity. Br J Clin Pharmacol 2013; 75:497-506. [PMID: 22765278 DOI: 10.1111/j.1365-2125.2012.04373.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 06/25/2012] [Indexed: 12/29/2022] Open
Abstract
AIM Pegylated interferon-based therapy is recommended for treatment of hepatitis C virus (HCV) infection. Because interferons are known to down-regulate hepatic cytochrome P450 (CYP) enzymes, which are involved in drug metabolism and clearance, there is a need to investigate the effect of peginterferon (PEG-IFN) alfa-2a (40KD) on the activity of these enzymes in vivo. METHODS Fourteen healthy, male volunteers aged 18 to 45 years were recruited into an open label, two period, single centre study in which CYP enzyme activity was measured by administration of the selectively metabolized probe drugs theophylline (CYP1A2), tolbutamide (CYP2C9), mephenytoin (CYP2C19), debrisoquine (CYP2D6) and dapsone (CYP3A4) on day 1 of the study. PEG-IFN alfa-2a (40KD) 180 μg was given subcutaneously each week from day 15 to 36, and probe drugs were re-administered on day 37. Probe drugs and metabolites were quantified in plasma or urine samples and used to derive pharmacokinetic parameters. RESULTS PEG-IFN alfa-2a (40KD) significantly increased the area under the serum drug concentration vs. time curve (AUC(0,∞)) for theophylline by 24%, with a reduction in the mean oral clearance of theophylline of 20%. There were no effects on the pharmacokinetics of any of the other probe drugs. The incidence of adverse events was as expected in subjects receiving pegylated interferon. CONCLUSION These results suggest there may be an inhibitory effect of PEG-IFN alfa-2a (40KD) on CYP1A2. PEG-IFN alfa-2a (40KD) had no effect on CYP2C9, CYP2C19, CYP2D6 or CYP3A4 in healthy subjects.
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Affiliation(s)
- Barbara J Brennan
- Department of Clinical Pharmacology, Hoffmann-La Roche Inc., Nutley, NJ 07110, USA.
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Lee S, Kim BH, Nam WS, Yoon SH, Cho JY, Shin SG, Jang IJ, Yu KS. Effect of CYP2C19 Polymorphism on the Pharmacokinetics of Voriconazole After Single and Multiple Doses in Healthy Volunteers. J Clin Pharmacol 2013; 52:195-203. [DOI: 10.1177/0091270010395510] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Orengo-Mercado C, Nieves B, López L, Vallés-Ortiz N, Renta JY, Santiago-Borrero PJ, Cadilla CL, Duconge J. Frequencies of Functional Polymorphisms in Three Pharmacokinetic Genes of Clinical Interest within the Admixed Puerto Rican Population. ACTA ACUST UNITED AC 2013; 4. [PMID: 24040574 DOI: 10.4172/2153-0645.1000113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE This cross-sectional study was aimed at determining the allele frequencies for the CYP2C19*2, CYP2C19*3, CYP2D6*10 and PON1 (rs662) polymorphisms in the Puerto Rican population. The CYP2C19, CYP2D6 and PON1 genes are known to be associated with functional changes in drug metabolism and activation. Individuals carrying the aforementioned polymorphisms are at a higher risk of suffering from drug-induced adverse events and/ or unresponsiveness from a variety of drugs that includes antidepressants, atypical antipsychotics and antiplatelet compounds. Information on the frequency of these polymorphisms is more commonly found on homogeneous populations, but is scarce in highly heterogeneous populations like Hispanics, as in the case of Puerto Ricans. METHOD Genotyping was carried out in 100 genomic DNA samples from dried blood spots supplied by the Puerto Rican Newborn Screening program using Taqman® Genotyping Assays. RESULTS The Minor Allele Frequencies (MAF) obtained were 9% for CYP2C19*2 and CYP2D6*10, 50% for PON1 (rs662), while the CYP2C19*3 variant was not detected in our study. Furthermore, Hardy Weinberg equilibrium analysis was assessed as well as a comparison between Puerto Rico and other reference populations using a Z-test for proportions. CONCLUSION The observed allele and genotype frequencies on these relevant pharmacogenes in Puerto Ricans were more closely related to those early reported in two other reference populations of Americans (Mexicans and Colombians).
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Affiliation(s)
- Carmelo Orengo-Mercado
- Department of Biochemistry, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico, USA
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de Andrés F, Sosa-Macías M, Lazalde-Ramos BP, Naranjo MEG, Tarazona-Santos E, LLerena A. Evaluation of drug-metabolizing enzyme hydroxylation phenotypes in Hispanic populations: the CEIBA cocktail. ACTA ACUST UNITED AC 2013; 28:135-46. [DOI: 10.1515/dmdi-2013-0020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/16/2013] [Indexed: 11/15/2022]
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Noubarani M, Kobarfard F, Motevalian M, Keyhanfar F. Variation in omeprazole pharmacokinetics in a random Iranian population: a pilot study. Biopharm Drug Dispos 2012; 33:324-31. [PMID: 22890488 DOI: 10.1002/bdd.1805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Omeprazole is metabolized in the liver mainly by the polymorphic CYP2C19 enzyme. Considerable ethnic differences have been reported in the pharmacokinetics of omeprazole. The present study was conducted to evaluate the pharmacokinetic parameters of omeprazole after a single oral administration to a random Iranian population. Thirty healthy male subjects, aged 24-31 years, weighing 60-98 kg completed the study. Plasma concentrations of omeprazole were measured over a 12 h period after administration of a single oral dose of 20 mg omeprazole. The pharmacokinetic parameters were calculated from the plasma concentration-time profiles. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to quantify 5-hydroxyomeprazole. The mean area under the concentration-time curve (AUC) from time zero to infinity (AUC(∞) ) values of omeprazole and the corresponding coefficient of variation (CV%) was 987.3 ng h/ml (65%). In general, most subjects showed a normal distribution. Only one subject showed a very high AUC compared with the corresponding mean AUC level. This subject had the highest half-life and the lowest rate of elimination. The omeprazole metabolic ratio for this subject was 2.9, while for the others it was in the range 0.12-0.56. These results are consistent with previous literature that showed the existence of interindividual variability in omeprazole pharmacokinetics, even within a single ethnic group. Differences in the pharmacokinetics could be due to differences in the genetic make-up of subjects as found in their omeprazole metabolic ratios.
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Affiliation(s)
- Maryam Noubarani
- Department of Pharmacology and Toxicology, Zanjan University of Medical Sciences, Zanjan, Iran
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Teh LK, Bertilsson L. Pharmacogenomics of CYP2D6: molecular genetics, interethnic differences and clinical importance. Drug Metab Pharmacokinet 2011; 27:55-67. [PMID: 22185816 DOI: 10.2133/dmpk.dmpk-11-rv-121] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
CYP2D6 has received intense attention since the beginning of the pharmacogenetic era in the 1970s. This is because of its involvement in the metabolism of more than 25% of the marketed drugs, the large geographical and inter-ethnic differences in the genetic polymorphism and possible drug-induced toxicity. Many interesting reviews have been published on CYP2D6 and this review aims to reinstate the importance of the genetic polymorphism of CYP2D6 in different populations as well as some clinical implications and important drug interactions.
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Affiliation(s)
- Lay Kek Teh
- Pharmacogenomics Centre PROMISE, Faculty of Pharmacy, Universiti Teknologi MARA, Selangor DE, Malaysia.
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Brennan M, Williams JA, Chen Y, Tortorici M, Pithavala Y, Liu YC. Meta-analysis of contribution of genetic polymorphisms in drug-metabolizing enzymes or transporters to axitinib pharmacokinetics. Eur J Clin Pharmacol 2011; 68:645-55. [PMID: 22170007 DOI: 10.1007/s00228-011-1171-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 11/11/2011] [Indexed: 02/07/2023]
Abstract
PURPOSE Axitinib, an orally administered inhibitor of vascular endothelial growth factor 1, 2 and 3, is primarily metabolized by cytochrome P450 (CYP) 3A4/5 but is also a substrate for CYP1A2, CYP2C19, UDP-glucuronosyltransferase (UGT)1A1 and the drug transporters P-glycoprotein (encoded by the ABCB1 gene) and OATP1B1 (encoded by SLC01B1). The potential contribution of polymorphisms in genes encoding these enzymes and transporters to axitinib pharmacokinetic variability was assessed. METHODS A fixed effects meta-analysis was performed using data pooled from 11 healthy volunteer clinical pharmacology trials to investigate the potential association between axitinib exposure and major polymorphisms in these genes following a 5-mg dose of axitinib. RESULTS Up to 15 variant alleles were evaluated and up to 315 healthy volunteers per polymorphism were assayed. None of the polymorphisms analysed was a statistically significant predictor of axitinib pharmacokinetic variability. Amongst genotypes and inferred phenotypes, CYP2C19 genotype and the ABCB1 (G2677T/A) polymorphism were the closest to statistical significance in influencing axitinib pharmacokinetic variability after multiple-testing adjustment. However, no enzyme or transporter genotype/inferred phenotype contributed >5% to the overall pharmacokinetic variability of axitinib. CONCLUSIONS No statistically significant associations between the specific polymorphisms analysed and axitinib plasma exposure were observed, suggesting that genotype- or inferred phenotype-based adjustment of axitinib dose in individual subjects is not warranted.
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Affiliation(s)
- Meghan Brennan
- Pfizer Research Center of Emphasis for DNA and Biofluids-Biobank, Groton, CT, USA
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Ginsburg OM, Love RR. Breast cancer: a neglected disease for the majority of affected women worldwide. Breast J 2011; 17:289-95. [PMID: 21410589 DOI: 10.1111/j.1524-4741.2011.01067.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Recent progress with declines in mortality in some high-income countries has obscured the fact that for the majority of women worldwide who are newly diagnosed, breast cancer is a neglected disease in the context of other numerically more frequent health problems. For this growing majority, it is also an orphan disease, in that detailed knowledge about tumor characteristics and relevant host biology necessary to provide even basic care is absent. With the possible exception of nutritional recommendations, current international cancer policy and planning initiatives are irrelevant to breast cancer. The progress that has occurred in high-income countries has come at extraordinary fiscal expense and patient toxicity, which of themselves suggest nonrelevance to women and healthcare practitioners in middle- and low-income countries. The implications of these circumstances appear clear: if the promise of the now 60-year-old Declaration of Human Rights that the fruits of medical science accrue to all mankind is to be realized with respect to breast cancer, a basic and translational global research initiative should be launched.
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Affiliation(s)
- Ophira M Ginsburg
- Women's College Research Institute, Department of Medicine, University of Toronto, 790 Bay Street #708, Ontario, Canada.
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Yang JC, Lin CJ. CYP2C19 genotypes in the pharmacokinetics/pharmacodynamics of proton pump inhibitor-based therapy of Helicobacter pylori infection. Expert Opin Drug Metab Toxicol 2010; 6:29-41. [PMID: 19968574 DOI: 10.1517/17425250903386251] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
IMPORTANCE OF THE FIELD Proton pump inhibitors (PPIs) are potent gastric acid inhibitors. Therapies with a PPI and antibiotics are used to cure Helicobacter pylori (H. pylori) infection, which is closely related to many gastrointestinal diseases. Most PPIs are mainly metabolized by cytochrome 2C19 (CYP2C19). The genetic polymorphisms of CYP2C19 may lead to the differences in pharmacokinetics (PK), pharmacodynamics (PD) and clinical efficacy of PPIs. AREAS COVERED IN THIS REVIEW The roles of PPIs on the eradication of H. pylori are summarized. The impact f CYP2C19 polymorphism on the PK and PD of PPIs is addressed and related to the present status of therapy for H. pylori infection. The opinions on the strategy of PPIs-based therapies of H. pylori infection are provided. WHAT THE READER WILL GAIN Update the factors that may influence the PPIs-based therapies of H. pylori infection. TAKE HOME MESSAGE The eradication rates of H. pylori infection are significantly different between patients who are CYP2C19 extensive metabolizers and poor metabolizers, partly because of the differences in the PK and PD of PPIs. Nonetheless, the differences can be improved by adjusting the regimens of PPIs and using antibiotics that have less H. pylori-resistance.
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Affiliation(s)
- Jyh-Chin Yang
- National Taiwan University, Hospital and College of Medicine, Department of Internal Medicine, Taipei, Taiwan
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Jin SK, Kang TS, Eom SO, Kim JI, Lee HJ, Roh J. CYP2C19 haplotypes in Koreans as a marker of enzyme activity evaluated with omeprazole. J Clin Pharm Ther 2009; 34:437-46. [PMID: 19583677 DOI: 10.1111/j.1365-2710.2008.01012.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND OBJECTIVE CYP2C19 is clinically important in Korea because of the relatively high incidence of poor metabolizers in the population. To fully understand the genetic mechanism of the CYP2C19 defect in poor metabolizers, all variants need to be studied simultaneously. The aim of this study was to investigate the usefulness of CYP2C19 haplotypes as a marker of CYP2C19 enzyme activity in Koreans. METHODS We analysed the single nucleotide polymorphisms and haplotypes of the CYP2C19 gene in 150 healthy Koreans and found three major (frequency > 0.1) haplotypes (H1, H2 and H3). One oral dose of 40 mg omeprazole (Losec) was administered to 30 subjects grouped as H1/H1, H2/H2, H1/H2, H1/H3 and H2/H3. The pharmacokinetics of omeprazole and its metabolites, 5-hydroxyomeprazole and omeprazole sulphone, in those groups was analysed. RESULTS AND DISCUSSION The area under the plasma concentration-time curve (AUC(0-->infinity)) and elimination half-life (T(1/2)) of omeprazole were significantly greater in the H2/H2 and H2/H3 groups than in the H1/H1 group (P < 0.05), whereas the metabolic ratios of omeprazole to 5-hydroxyomeprazole were also markedly higher. CONCLUSION Although a specific SNP of CYP2C19 may be predictive of enzyme activity, haplotyping is more reliable for identifying poor metabolizers in populations with variant alleles other than CYP2C19*2 and *3 alleles.
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Affiliation(s)
- S K Jin
- Department of Pharmacological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul, South Korea
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Neafsey P, Ginsberg G, Hattis D, Sonawane B. Genetic polymorphism in cytochrome P450 2D6 (CYP2D6): Population distribution of CYP2D6 activity. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2009; 12:334-61. [PMID: 20183526 DOI: 10.1080/10937400903158342] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Cytochrome P-450 2D6 (CYP2D6) is involved in the metabolism of many therapeutic drugs even though the enzyme represents a small proportion of the total CYP content of human liver. In vivo phenotyping with probe drug substrates such as debrisoquine and dextromethorphan showed a clear separation between poor metabolizers (PM) and extensive metabolizers (EM). This polymorphism may affect susceptibility to environmental disease, as suggested by molecular epidemiologic studies that found an association between CYP2D6 metabolizer phenotype and cancer risk; however, this association is not consistent. There are only a few examples of CYP2D6 involvement in toxicant mechanism of action, but this has not been extensively studied. Gene probe studies documented a number of genetic polymorphisms that underlie CYP2D6 metabolizer phenotypes. The EM group carries the wild-type (*1) or active (*2) variant alleles, while the PM group carries the *3, *4, *5, or *6 alleles, all of which code for a protein that has lower or null CYP2D6 activity. The current analysis characterizes (a) influence of genotype on phenotype based upon in vivo metabolism studies of probe drugs and (b) frequency of the major genotypes in different population groups is also characterized. These data were then incorporated into Monte Carlo modeling to simulate population distributions of CYP2D6 activity. This analysis reproduced the bimodal distributions commonly seen in phenotyping studies of Caucasians and found extensive population variability in enzyme activity, as indicated by the 9- to 56-fold difference between the PM modal median and the total population median CYP2D6 activity. This substantial degree of interindividual variability in CYP function indicates that assessments involving CYP2D6 substrates need to consider the full distribution of enzyme activity in refining estimates of internal dose in health assessments of xenobiotics.
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Preskorn SH, Nichols AI, Paul J, Patroneva AL, Helzner EC, Guico-Pabia CJ. Effect of desvenlafaxine on the cytochrome P450 2D6 enzyme system. J Psychiatr Pract 2008; 14:368-78. [PMID: 19057238 DOI: 10.1097/01.pra.0000341891.43501.6b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The cytochrome P450 2D6 (CYP2D6) enzyme is responsible for metabolizing approximately 25% of pharmaceutical agents. Individuals with impaired CYP2D6 metabolism and those concomitantly receiving agents that inhibit CYP2D6 can have variations in concentrations of such medications and their metabolites. METHODS Five studies assessing the interaction between desvenlafaxine and CYP2D6 are reviewed. Study 1 compared desvenlafaxine area under the plasma concentration-versus-time curve (AUC) in CYP2D6 extensive metabolizers (EMs) and poor metabolizers (PMs) after administration of 100 mg of desvenlafaxine or 75 mg of venlafaxine extended release (ER). Studies 2 to 5 assessed the effect of concomitant administration of desvenlafaxine 100 mg (studies 2, 4, and 5) or 400 mg (study 3), paroxetine (20 mg, study 4), and duloxetine (30 mg twice daily; study 5) on the CYP2D6 probe desipramine. RESULTS In study 1, there was no significant difference in mean desvenlafaxine AUC between the CYP2D6 EMs and PMs (-11%; P=0.641) who were administered desvenlafaxine. However, PMs receiving venlafaxine ER had significantly higher venlafaxine and lower desvenlafaxine AUCs compared with EMs (+350% and -74%, respectively; P<0.001 for each). In studies 2, 4, and 5, the mean increases in desipramine AUC with concomitant administration of desvenlafaxine 100 mg ranged from 17% to 36%; the increase with concomitant administration of desvenlafaxine 400 mg (study 3) was 90%. Paroxetine and duloxetine produced increases in mean desipramine AUC of 419% and 122%, respectively, which were significantly greater than the increases seen with desvenlafaxine 100 mg (P<0.001 for each comparison). CONCLUSIONS Based on the findings presented here, desvenlafaxine is expected to have a low risk for variability in efficacy and safety/tolerability resulting from CYP2D6 polymorphisms or drug-drug interactions when coadministered with CYP2D6 substrates or inhibitors.
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Affiliation(s)
- Sheldon H Preskorn
- Clinical Research Institute and University of Kansas School of Medicine, Wichita, KS 67211, USA.
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Jin SK, Chung HJ, Chung MW, Kim JI, Kang JH, Woo SW, Bang S, Lee SH, Lee HJ, Roh J. Influence ofCYP2D6*10on the pharmacokinetics of metoprolol in healthy Korean volunteers. J Clin Pharm Ther 2008; 33:567-73. [DOI: 10.1111/j.1365-2710.2008.00945.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ismail R, Hussein A, Teh LK, Isa MN. CYP2D6 phenotypes among Malays in Malaysia. J Clin Pharm Ther 2008. [DOI: 10.1111/j.1365-2710.2000.00304.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Greene RE, Tsang V. Hormonal Therapy for the Treatment of Postmenopausal Breast Cancer Patients. J Pharm Pract 2008. [DOI: 10.1177/0897190008315055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Breast cancer is the most common cancer diagnosed and the second leading cause of cancer-related death in women. The majority of breast cancers diagnosed in postmenopausal women are hormone receptor positive and involve therapy with hormonal agents. Tamoxifen, a selective estrogen-receptor modulator, has been the mainstay of hormonal therapy since the 1970s. The more recent approval and success of aromatase inhibitors, such as anastrozole, letrozole, and exemestane, have seen these agents move to the front line of therapy for postmenopausal women with hormone-positive breast cancer in the adjuvant and metastatic settings. Fulvestrant, a selective estrogen receptor— downregulator, provides an additional hormonal therapy with a novel mechanism of action. This article reviews the current literature available regarding the use of these agents for postmenopausal women with early stage or advanced breast cancer.
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Affiliation(s)
| | - Vivian Tsang
- South Texas Veterans Health Care System, San Antonio, Texas
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Wang L, Yu L, Zhang AP, Fang C, Du J, Gu NF, Qin SY, Feng GY, Li XW, Xing QH, He L. Serum prolactin levels, plasma risperidone levels, polymorphism of cytochrome P450 2D6 and clinical response in patients with schizophrenia. J Psychopharmacol 2007; 21:837-42. [PMID: 17715206 DOI: 10.1177/0269881107077357] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The object of this study is to assess 1) the relationship between plasma antipsychotic drug concentration, serum prolactin levels and the clinical efficacy of risperidone, 2) the relationship between the CYP2D6 polymorphisms and metabolizing of risperidone and 3) the role of 9-hydroxyrisperidone in elevating prolactin levels. One-hundred and eighteen Chinese schizophrenia patients (40 males, 78 females, age 15-60 years) were given risperidone at dosages ranging from 2-8 mg/day for 8 weeks. Clinical efficacy was determined using the Brief Psychiatric Rating Scores (BPRS). Serum prolactin levels were assayed before and after the 8 week treatment and plasma risperidone and 9-hydroxyrisperidone levels were also measured at the end of the 8-week treatment. The results showed there was no significant correlation between the concentration of active moiety and clinical response. Risperidone treatment significantly increased serum prolactin levels. Furthermore, changes of prolactin levels were not correlated with the clinical response. For the risperidone/ 9-hydroxyrisperidone ratio, there was a statistically significant difference among the CYP2D6*1/*1, *1/*10, *10/*10 genotypes (Kruskal-Wallis test, p = 0.012). No significant differences were found in the concentration of 9-hydroxyrisperidone and active moiety among the genotypes. In addition, the concentration of 9-hydroxyrisperidone was not significantly correlated with the increase of serum prolactin. In conclusion, our study has, for the first time, produced evidence that in Chinese schizophrenic patients, the metabolism of risperidone is dependent on CYP2D6. Neither changes in serum prolactin levels nor plasma concentration of active moiety were significantly correlated with clinical efficacy of risperidone. 9-hydroxyrisperidone may not play a predominant role in elevating serum prolactin level.
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Affiliation(s)
- Lei Wang
- Bio-X center, Shanghai Jiao Tong University, Shanghai, China, Institute for Nutritional Science, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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Lim HS, Ju Lee H, Seok Lee K, Sook Lee E, Jang IJ, Ro J. Clinical implications of CYP2D6 genotypes predictive of tamoxifen pharmacokinetics in metastatic breast cancer. J Clin Oncol 2007; 25:3837-45. [PMID: 17761971 DOI: 10.1200/jco.2007.11.4850] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The CYP3A and CYP2D6 enzymes play a major role in converting tamoxifen to its active metabolites. CYP3A is a highly inducible enzyme, regulated mainly by pregnane X receptor (PXR). This study assessed the association between genetic polymorphisms of CYP2D6 and PXR, and tamoxifen pharmacokinetics (PK) and clinical outcomes in patients with breast cancer. PATIENTS AND METHODS Plasma concentrations of tamoxifen and its metabolites were measured. Common alleles of CYP2D6 and PXR were identified in 202 patients treated with tamoxifen 20 mg daily for more than 8 weeks. Twelve of the 202 patients and an additional nine patients with metastatic breast cancer receiving tamoxifen were assessed for clinical outcome in correlation with genotypes. RESULTS Patients carrying CYP2D6*10/*10 (n = 49) demonstrated significantly lower steady-state plasma concentrations of 4-hydroxy-N-desmethyltamoxifen and 4-hydroxytamoxifen than did those with other genotypes (n = 153; 4-hydroxy-N-desmethyltamoxifen: 7.9 v 18.9 ng/mL, P < .0001; 4-hydroxytamoxifen: 1.5 v 2.6 ng/mL, P < .0001), whereas no difference by PXR genotypes was found. CYP2D6*10/*10 was significantly more frequent among nonresponders with MBC (100% v 50%, P = .0186). In Cox proportional hazard analysis, CYP2D6 genotype and number of disease sites were significant factors affecting time to progression (TTP). The median TTP for patients receiving tamoxifen was shorter in those carrying CYP2D6*10/*10 than for others (5.0 v 21.8 months, P = .0032) CONCLUSION CYP2D6*10/*10 is associated with lower steady-state plasma concentrations of active tamoxifen metabolites, which could possibly influence the clinical outcome by tamoxifen in Asian breast cancer patients.
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Affiliation(s)
- Hyeong-Seok Lim
- Research Institute and Hospital, National Cancer Center, Madu1-dong, Ilsan-gu, Goyang-si, Gyeonggi-do, Republic of Korea
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Nakamoto K, Kidd JR, Jenison RD, Klaassen CD, Wan YJY, Kidd KK, Zhong XB. Genotyping and haplotyping of CYP2C19 functional alleles on thin-film biosensor chips. Pharmacogenet Genomics 2007; 17:103-14. [PMID: 17301690 DOI: 10.1097/fpc.0b013e32801152c2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Numerous functional polymorphisms in the CYP2C19 gene have been identified; some alleles (e.g. CYP2C19*2 and CYP2C19*3) are associated with poor metabolism of CYP2C19 substrate drugs. Studies have found that the proportion of poor metabolizers, explained by CYP2C19*2 and CYP2C19*3, varies from less than 50% to more than 90% of poor metabolizers. Therefore, phenotype-genotype correlation studies should cover more than CYP2C19*2 and CYP2C19*3. A broader coverage, however, requires an easy-to-use and high-throughput genotyping platform. This broader coverage should also include the recently identified functional allele, CYP2C19*10, which involves a nucleotide change adjacent to the altered nucleotide change in CYP2C19*2. The currently used restriction fragment length polymorphism-based method for genotyping CYP2C19*2 cannot distinguish between CYP2C19*2 and CYP2C19*10. We aim to develop a simple platform that can genotype all CYP2C19 functional alleles. METHODS We have developed a thin-film biosensor chip platform to genotype 16 exonic CYP2C19 variants, including two sets of two adjacent single nucleotide polymorphisms and 12 single single nucleotide polymorphisms, using a ligation strategy. RESULTS We demonstrate that this is a rapid, accurate, and inexpensive method for genotyping CYP2C19 variants using individual's genomic DNA samples. We further demonstrate that this genotyping platform can be used to construct a haplotype structure of the CYP2C19 variants in a population, and to assign a haplotype combination to each individual on the basis of his/her genotype results. CONCLUSION This assay can be applied in pharmacogenomic studies in both basic research and clinical laboratories. It is also an ideal technology for pharmacogenomic tests in both developed and developing countries.
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Affiliation(s)
- Kaori Nakamoto
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, USA
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Kim YM, Yoo SH, Kang RY, Kim MJ, Bae YY, Lee YK, Jeon SJ, Chon KJ, Shin SM, Kim SG, Park KH, Son IJ. Identifying drugs needing pharmacogenetic monitoring in a Korean hospital. Am J Health Syst Pharm 2007; 64:166-75. [PMID: 17215467 DOI: 10.2146/ajhp050490] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE A decision matrix for identifying drugs for which pharmacogenetic drug monitoring (PDM) provides the greatest benefit in a Korean setting is described. SUMMARY We developed a decision matrix including the ethnic frequency of clinically relevant polymorphic cytochrome P-450 (CYP) enzymes, and the metabolic profiles and adverse drug reactions of drugs. Using the developed decision matrix based on the population allele frequencies of CYP enzymes, we identified potential candidates for PDM among the most commonly used drugs at Seoul National University Hospital (SNUH). Collectively, 17 of these drugs were largely metabolized by at least one polymorphic CYP enzyme. Pharmacogenetic information was used to identify CYP2C9, CYP2C19, and CYP2D6 as the major CYP enzymes of clinical importance for pharmacologic effect and safety in Koreans. The frequencies of poor and intermediate metabolizers among Koreans were 0% and 2.3-12% for CYP2C9, 12% and 42% for CYP2C19, and 0.44% and 28% for CYP2D6, respectively. The frequency of ultrarapid metabolizers of CYP2D6 was 2.28%. The decision matrix and pharmacogenetic information were used to identify seven drugs for PDM: warfarin, glimepiride, diazepam, amitriptyline, nortriptyline, codeine, and oxycodone. This approach can be applied to other institutional hospitals or other ethnic populations and would be helpful for advancing pharmacy practice. Further work is required to assess the practical and potential clinical relevance of pharmacogenetic variations on drugs of interest before the implementation of PDM. CONCLUSION A decision matrix helped identify drugs for which PDM provides the greatest potential benefit at one Korean hospital.
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Affiliation(s)
- Young Mi Kim
- Department of Pharmacy, Seoul National University Hospital, Seoul, Korea
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Jakobsson J, Palonek E, Lorentzon M, Ohlsson C, Rane A, Ekström L. A novel polymorphism in the 17β-hydroxysteroid dehydrogenase type 5 (aldo-keto reductase 1C3) gene is associated with lower serum testosterone levels in caucasian men. THE PHARMACOGENOMICS JOURNAL 2006; 7:282-9. [PMID: 16983398 DOI: 10.1038/sj.tpj.6500419] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genetic variation in the androgen metabolizing enzymes is important to identify and feature as they may influence the risk of prostate cancer and help clarify the etiology of the disease. Human 17beta-hydroxysteroid dehydrogenase type 5 (AKR1C3) is highly expressed in the prostate gland and plays a major role in the formation and metabolism of androgens. We identified five novel polymorphisms in the AKR1C3 gene. One of those an A>G substitution in exon 2 that confers a Glu77Gly change occurred in 4.8% in Caucasians but was completely absent in Orientals. Interestingly, the testosterone level in serum was significantly lower in subjects with the Gly77 allele. A promoter A>G polymorphism was associated with significantly altered promoter activity in reporter constructs, but was not associated with any change in testosterone levels. In conclusion, the Glu77Gly polymorphism is associated with lower testosterone levels in serum.
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Affiliation(s)
- J Jakobsson
- 1Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
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Soundararajan CC, Adhin A, Tripathi M, Prasad HK, Jain S, Vivekanandhan S. Association of CYP2D6 100 C > T and 2850 C > T polymorphisms with generalized tonic clonic seizures among Indians. J Neural Transm (Vienna) 2006; 113:1873-6. [PMID: 16835697 DOI: 10.1007/s00702-006-0494-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 02/01/2006] [Indexed: 11/25/2022]
Abstract
Multiple avenues of research have provided evidence for the role of genetic and environmental factors in epilepsy. Previous studies indicated an association of debrisoquine hydroxylase (CYP2D6) with susceptibility to epilepsy. In this study, association of CYP2D6 100C > T and 2850C > T polymorphisms with generalized tonic clonic seizures (GTCS) among Indians has been analysed using case-control approach. A significant association of 2850C > T (P = 0.015) has been observed. Comparison between phenytoin toxic and others among patients showed no association of these polymorphisms with phenytoin toxicity.
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Affiliation(s)
- C C Soundararajan
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
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Lee SY, Sohn KM, Ryu JY, Yoon YR, Shin JG, Kim JW. Sequence-based CYP2D6 Genotyping in the Korean Population. Ther Drug Monit 2006; 28:382-7. [PMID: 16778723 DOI: 10.1097/01.ftd.0000211823.80854.db] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
For clinical application of pharmacogenetic tests, quantitative prediction of enzyme activity based on accurate determination of genotype is essential. There has been limited information available on the genetic polymorphism of CYP2D6 in the Korean population. In this study, CYP2D6 genotypes were assessed in 400 Korean subjects. Twenty-eight different CYP2D6 alleles and 35 genotypes were detected. On the basis of the genotype determined, the frequency of poor metabolizers and ultrarapid metabolizers were 0.22% and 1.25%, respectively. The CYP2D6 activity expected in regard to different allele combinations varies widely within the extensive and intermediate metabolizer groups. The frequencies of CYP2D6*10 and CYP2D6*5 were 45.00% and 6.13%, respectively. CYP2D6*10xN was found in 4 out of 9 cases with a CYP2D6 duplication. Fifteen heterozygotes for *41 were noted. In addition, the authors measured plasma concentrations of 16 healthy volunteers after administration of nortriptyline and identified the impact of the CYP2D6 genotype on nortriptyline metabolism. This is the first large-scale study to examine the genetic polymorphism of CYP2D6 using sequence-based genotyping in an Asian population. Our results further the understanding of CYP2D6 pharmacogenetics and could be helpful for future clinical studies in the Asian population.
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Affiliation(s)
- Soo-Youn Lee
- Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Alonso-Navarro H, Jiménez-Jiménez FJ, García-Agúndez JA. Papel del polimorfismo genético CYP2C19 en los efectos adversos a fármacos y en el riesgo para diversas enfermedades. Med Clin (Barc) 2006; 126:697-706. [PMID: 16759580 DOI: 10.1157/13088772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
There are a great number of polymorphic genes in the human genome. Many of them codify enzymes that metabolizes drugs and xenobiotic agents, including carcinogens. Among the better known of them, there are a number of isozymes of the microsomal oxidative system (CYP3A4, CYP2C9, CYP2C19 y CYP2D6). This article reviews the following issues: a) frequency of presentation of the "poor metabolizer" genotype and/or phenotype for substrates of CYP2C19; b) role of CYP2C19 polymorphism on the metabolism of some drugs (mephenytoine and other antiepileptic drugs, proton pump inhibitors, several antidepressants and anxyolitics, the antimalaria aggent proguanyl, and propranolol, among others, use this metabolic pathway), and c) possible role of CYP2C19 polymorphism in the risk for development of neoplasia and other diseases (systemic lupus erythematosus, psoriasis, hip osteonecrosis, Alzheimer's disease, amyotrophic lateral sclerosis, essential tremor).
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Soyama A, Saito Y, Ohno Y, Komamura K, Kamakura S, Kitakaze M, Tomoike H, Ozawa S, Sawada JI. Diverse Structures of Chimeric CYP-REP7/6-Containing CYP2D6 and a Novel Defective CYP2D6 Haplotype Harboring Single-type *36 and CYP-REP7/6 in Japanese. Drug Metab Pharmacokinet 2006; 21:395-405. [PMID: 17072093 DOI: 10.2133/dmpk.21.395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chimeric REP7/6 has been used as a marker of CYP2D6 deletion, such as for CYP2D6*5. However, the CYP2D6*10D (*10D) haplotype found in a Japanese population consist of CYP2D6*10B, CYP2D7P-derived 3'-flanking region, and a chimeric repetitive sequence, CYP-REP7/6 (REP7/6) (Ishiguro et al. Clin. Chim. Acta. 2004: 347, 217-221). From our analysis, REP7/6 was found in 26 out of 254 Japanese subjects. Thus, the REP7/6-containing CYP2D6 genes (2D6-REP7/6) were analyzed in detail. In order to specifically detect the 2D6-REP7/6 structure, primers were designed in CYP2D6 intron 6 and the REP7/6 3'-flanking region. Among 26 subjects analyzed by PCR, 5 had 2D6-REP7/6. The other 21 subjects were confirmed to have *5 by another *5-specific primer set. Three out of five subjects with 2D6-REP7/6 had the *10D structure. However, further analysis by PCR and sequencing revealed that their haplotypes were further divided into tandem-type *36-*10D (n=2) and single-type *10D (n=1). The remaining two subjects had a novel type of a *36-containing defective structure that consists of CYP2D6*36 and 3'-flanking REP7/6 (single-type *36-REP7/6). Then, REP7/6 sequences in *5, *10D, *36-*10D, and single-type *36 were determined and classified into 5 types: types A to D for *5, type E for *10D and *36-*10D, and type F for *36. These findings could be useful for accurate determination of *5 and REP7/6-harboring aberrant CYP2D6 haplotypes.
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Affiliation(s)
- Akiko Soyama
- Project Team for Pharmacogenetics, National Institute of Health Sciences, Kamiyoga, Tokyo, Japan
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Jaquenoud Sirot E, van der Velden JW, Rentsch K, Eap CB, Baumann P. Therapeutic Drug Monitoring and Pharmacogenetic Tests as Tools in Pharmacovigilance. Drug Saf 2006; 29:735-68. [PMID: 16944962 DOI: 10.2165/00002018-200629090-00001] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Therapeutic drug monitoring (TDM) and pharmacogenetic tests play a major role in minimising adverse drug reactions and enhancing optimal therapeutic response. The response to medication varies greatly between individuals, according to genetic constitution, age, sex, co-morbidities, environmental factors including diet and lifestyle (e.g. smoking and alcohol intake), and drug-related factors such as pharmacokinetic or pharmacodynamic drug-drug interactions. Most adverse drug reactions are type A reactions, i.e. plasma-level dependent, and represent one of the major causes of hospitalisation, in some cases leading to death. However, they may be avoidable to some extent if pharmacokinetic and pharmacogenetic factors are taken into consideration. This article provides a review of the literature and describes how to apply and interpret TDM and certain pharmacogenetic tests and is illustrated by case reports. An algorithm on the use of TDM and pharmacogenetic tests to help characterise adverse drug reactions is also presented. Although, in the scientific community, differences in drug response are increasingly recognised, there is an urgent need to translate this knowledge into clinical recommendations. Databases on drug-drug interactions and the impact of pharmacogenetic polymorphisms and adverse drug reaction information systems will be helpful to guide clinicians in individualised treatment choices.
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Jakobsson J, Karypidis H, Johansson JE, Roh HK, Rane A, Ekström L. A functional C-G polymorphism in the CYP7B1 promoter region and its different distribution in Orientals and Caucasians. THE PHARMACOGENOMICS JOURNAL 2005; 4:245-50. [PMID: 15007371 DOI: 10.1038/sj.tpj.6500236] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cytochrome P450 (CYP) 7B1 is involved in many metabolic processes including androgen metabolism. Genetic variation in the CYP7B1 gene may play a role in predisposition to prostate cancer. Here, we screened the human CYP7B1 gene for possible polymorphisms. Only one single polymorphism was detected, a C-G change in the promoter -104 base pair from the transcription start site. The allele frequency was investigated in Swedish men and compared to a Korean population, as it is known that the frequency of prostate cancer is low among Orientals. We found that the frequency of the G-allele was 4.04% in Swedes (n=150) but only 0.33% among Koreans (n=153). Computer analysis indicated that the two variants bind with different affinities to a CCAAT-box binding protein. Expression studies with reporter constructs showed significantly higher transcriptional activity of the G variant in Hek293 cells (2.7-fold, P<0.05). In conclusion, we report here for the first time the detection of a single polymorphism in the CYP7B1 gene. This polymorphism is associated with phenotypic differences in an expression system and a widely different allele frequency in two ethnic populations, with great differences in the incidence of prostate cancer.
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Affiliation(s)
- J Jakobsson
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
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Roh HK, Kim PS, Lee DH, Tybring G, Sagar M, Park CS, Seensalu R, Bertilsson L. Omeprazole treatment of Korean patients: effects on gastric pH and gastrin release in relation to CYP2C19 geno- and phenotypes. Basic Clin Pharmacol Toxicol 2005; 95:112-9. [PMID: 15447734 DOI: 10.1111/j.1742-7843.2004.950302.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study aimed to investigate the effect of omeprazole on intragastric pH and gastrin release as well as the plasma concentration of omeprazole in relation to CYP2C19 genotypes after repeated doses in Korean patients. Twenty-six Korean patients with acid related disease were genotyped for CYP2C19 by allele specific PCR (wt/wt, CYP2C19*1/*1; wt/mut, CYP2C19*1/*2 or *1/*3; mut/mut, CYP2C19*2/*2, *2/*3 or *3/*3). Intragastric pH was monitored during 24 hr, and the plasma concentrations of omeprazole, hydroxyomeprazole, omeprazole sulfone and meal-stimulated gastrin were measured during 4 hr before and after 8 consecutive daily doses of 20 mg omeprazole. Unexpectedly the AUCs of omeprazole in the three genotypes were similarly high on Day 8. The mean 24 hr pH increased significantly in all three genotypes (paired t-test; P<0.0001), and the AUCs (4 hr) of gastrin in all patients increased markedly from 129+/-73 to 298+/-142 pMhr (P<0.0001). However, there was no statistically significant difference between the three genotypes in the mean pH and gastrin AUCs on Day 8. After 8 consecutive doses of 20 mg omeprazole, the gastric pH and the plasma gastrin were increased significantly in all three CYP2C19 genotypes, which were confirmed by high plasma concentrations of omeprazole in all three genotype groups. We suggest that the reason why the wt/wt had high concentrations of omeprazole similar to those in the other two genotype groups is that some of them were old with low CYP2C19 activity. In these patients omeprazole accumulated from the first to the eighth dose similar to that in the heterozygotes.
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Affiliation(s)
- Hyung-Keun Roh
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
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Afshar M, Rouini M, Ala S. Dextromethorphan metabolic phenotyping in an Iranian population. Eur J Clin Pharmacol 2005; 60:849-54. [PMID: 15657780 DOI: 10.1007/s00228-004-0859-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Accepted: 10/18/2004] [Indexed: 11/30/2022]
Abstract
OBJECTIVE CYP2D6 polymorphism of drug metabolism represents an important source of interindividual and interethnic variation in drug response. Since this polymorphism has not been studied in an Iranian population, the present study was undertaken. METHODS Two hundred healthy unrelated Iranian subjects participated in this study. Phenotyping was based on high-performance liquid chromatography determination of the dextromethorphan/total dextrorphan molar ratios as metabolic ratios (MRs) in plasma samples collected at 3 h after oral administration of 30 mg dextromethorphan hydrobromide. Since the dextromethorphan detection limit of 5 ng/ml achieved in the simultaneous assay for dextromethorphan and its metabolites was not adequate to identify intermediate metabolizers (IMs), 80 of 200 samples selected randomly were also assayed using a modified, more sensitive procedure with a dextromethorphan detection limit of 1 ng/ml. RESULTS Poor and extensive metabolizers (EMs) could be identified distinctly. A 520-fold interindividual variation in dextromethorphan MRs was observed in this study. In contrast to undetectable dextrorphan and hydroxymorphinan concentrations, clearly determinable dextromethorphan concentrations higher than 10 ng/ml were observed in plasma samples of poor metabolizers (PMs). Considering the antimode of 0.3, five (2.5%, 95% confidence interval of 0.34-4.66) volunteers were identified as PMs. Using the more sensitive method, dextromethorphan was quantified in 4 (one PM) of 80 samples. Excluding the PM, a Shapiro-Wilk test indicated a non-normal distribution of MRs (P < 0.01) in the latter population. CONCLUSIONS From this study it can be concluded that the frequency of PMs in an Iranian population is 2.5% (95% confidence interval of 0.34-4.66). IMs could be identified using dextromethorphan plasma assays with detection limits of at least 1 ng/ml. However, the phenotype-genotype relationships in this respect remain to be established.
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Affiliation(s)
- Minoo Afshar
- Biopharmaceutics and Pharmacokinetics Division, Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, Iran
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Lee SY, Ki CS, Hong KS, Kim JW. A case report of a poor metabolizer of CYP2D6 presented with unusual responses to nortriptyline medication. J Korean Med Sci 2004; 19:750-2. [PMID: 15483356 PMCID: PMC2816343 DOI: 10.3346/jkms.2004.19.5.750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We present a case with decreased metabolic activity of CYP2D6, a cytochrome P450 enzyme catalyzing the metabolism of nortriptyline (NT). Conventional dosage regimen led to toxic plasma concentration of NT and adverse effects such as dry mouth, constipation, and dizziness in this case with genotype CYP2D6*5/*10B. This case suggests the clinical usefulness of pharmacogenetic testing in individualized dosage adjustments of NT.
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Affiliation(s)
- Soo-Youn Lee
- Department of Laboratory Medicine, Sungkyunkwan University School of Medicine Samsung Medical Center, Seoul, Korea
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Morrison A, Levy R. Toward individualized pharmaceutical care of East Asians: the value of genetic testing for polymorphisms in drug-metabolizing genes. Pharmacogenomics 2004; 5:673-89. [PMID: 15335288 DOI: 10.1517/14622416.5.6.673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Research into the relationship between genetics and drug response has focused on polymorphisms in genes that encode drug-metabolizing enzymes, particularly the genes of cytochrome P450 superfamily 2, which affect the clearance of the anticoagulant warfarin, proton pump inhibitors, tricyclic antidepressants, and many other clinically relevant drugs. Much of this work has targeted East Asians, a genetically distinguishable and populous group. Researchers have identified polymorphisms that inactivate gene function, compared polymorphism frequencies in East-Asian and Caucasian populations, and determined the effects on the pharmacokinetic parameters of drugs. Detection in an individual of polymorphisms known to inactivate a drug-metabolizing enzyme is predictive of poor metabolism of drugs processed by that pathway, which itself may be predictive of an atypical drug response. Genetic tests can be used to screen for individuals with poor metabolizer phenotypes, with the ultimate goal of predicting the clinical effects of drugs.
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Ng CH, Schweitzer I, Norman T, Easteal S. The emerging role of pharmacogenetics: implications for clinical psychiatry. Aust N Z J Psychiatry 2004; 38:483-9. [PMID: 15255819 DOI: 10.1080/j.1440-1614.2004.01400.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE This article aims to review the implications of pharmacogenetics for clinical psychiatry; these are discussed in the context of environmental and sociocultural factors. METHOD A selective literature review was conducted using Medline search and other relevant references available to the authors. RESULTS The individual differences in therapeutic and adverse effects of psychotropic drugs are largely determined by genetic factors. Recent advances in pharmacogenetics have highlighted the potential utility in predicting metabolic phenotypes, risks for side-effects and likelihood of drug response for the individual patient. CONCLUSIONS Genotyping, especially for drug metabolizing enzymes, could enable more rational, cost-effective and optimal prescribing in future psychopharmacotherapy. Although the advances of pharmacogenetics may have many benefits in clinical practice, the importance of non-genetic factors must also be considered as cultural and environmental factors significantly impinge on response to medications. To clarify the extent pharmacogenetics can be adopted in clinical practice to predict drug response in patients from diverse backgrounds, further studies in different ethnic groups and clinical settings are required.
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Affiliation(s)
- Chee Hong Ng
- The Melbourne Clinic, Department of Psychiatry, University of Melbourne, Victoria, Australia.
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Yusuf I, Djojosubroto MW, Ikawati R, Lum K, Kaneko A, Marzuki S. Ethnic and geographical distributions of CYP2C19 alleles in the populations of Southeast Asia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 531:37-46. [PMID: 12916779 DOI: 10.1007/978-1-4615-0059-9_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- Irawan Yusuf
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia.
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Bjornsson TD, Wagner JA, Donahue SR, Harper D, Karim A, Khouri MS, Murphy WR, Roman K, Schneck D, Sonnichsen DS, Stalker DJ, Wise SD, Dombey S, Loew C. A review and assessment of potential sources of ethnic differences in drug responsiveness. J Clin Pharmacol 2003; 43:943-67. [PMID: 12971027 DOI: 10.1177/0091270003256065] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The International Conference on Harmonization (ICH) E5 guidelines were developed to provide a general framework for evaluating the potential impact of ethnic factors on the acceptability of foreign clinical data, with the underlying objective to facilitate global drug development and registration. It is well recognized that all drugs exhibit significant inter-subject variability in pharmacokinetics and pharmacologic response and that such differences vary considerably among individual drugs and depend on a variety of factors. One such potential factor involves ethnicity. The objective of the present work was to perform an extensive review of the world literature on ethnic differences in drug disposition and responsiveness to determine their general significance in relation to drug development and registration. A few examples of suspected ethnic differences in pharmacokinetics or pharmacodynamics were identified. The available literature, however, was found to be heterologous, including a variety of study designs and research methodologies, and most of the publications were on drugs that were approved a long time ago.
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Kawanishi C. Genetic predisposition to neuroleptic malignant syndrome : implications for antipsychotic therapy. AMERICAN JOURNAL OF PHARMACOGENOMICS : GENOMICS-RELATED RESEARCH IN DRUG DEVELOPMENT AND CLINICAL PRACTICE 2003; 3:89-95. [PMID: 12749726 DOI: 10.2165/00129785-200303020-00002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The pathogenetic mechanism of neuroleptic malignant syndrome (NMS), a potentially lethal adverse effect of antipsychotics, is not well understood. In addition to acquired risk factors, clinical observations suggest a number of genetic factors predisposing patients to NMS. Recent findings in pharmacogenetics indicate that the genetic polymorphisms for drug-metabolizing enzymes, drug transporters, and possibly drug-targeting molecules, are associated with the interindividual differences in drug responses concerning both efficacy and adverse reactions. Genetic association studies have sought to identify polymorphisms influencing susceptibility to NMS, especially with respect to the dopamine D(2) receptor, serotonin receptor, and cytochrome p450 2D6. While a few candidate polymorphisms were associated with NMS, a large controlled study is needed to attain statistical power. On the other hand, NMS might include heterogeneous conditions with common characteristic symptoms but different causative mechanisms. Further analysis of individuals with identified genetic mutations or polymorphisms should advance our understanding of mechanisms underlying NMS.
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Affiliation(s)
- Chiaki Kawanishi
- Department of Psychiatry, Yokohama City University School of Medicine, Yokohama, Japan.
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Ismail R, Teh LK, Amir J, Alwi Z, Lopez CG. Genetic polymorphism of CYP2D6 in Chinese subjects in Malaysia. J Clin Pharm Ther 2003; 28:279-84. [PMID: 12911679 DOI: 10.1046/j.1365-2710.2003.00490.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although Malaysian Chinese share an origin with the mainland Chinese, their evolution has been influenced by intermarriages. With a gene such as CYP2D6, which is highly polymorphic, it is expected that the Malaysian Chinese would exhibit a polymorphism profile different from those of the Chinese populations in other geographical locations. OBJECTIVE To study the genotype distribution of CYP2D6 among the Chinese people in Malaysia. METHOD We obtained DNA from 236 Chinese individuals in Malaysia and used PCR-based methods to identify any common CYP2D6 alleles. RESULTS A total of 236 subjects were enrolled and were successfully genotyped. Malaysian Chinese were relatively heterogeneous in terms of their CYP2D6 genotypes with nine genotypes recorded. CYP2D6*4, *5, *9, *10 and *17 were detected with the most common genotype being *1/*10. No subject had genotypes that predicted poor metabolic activity. However, 40% showed genotypes (e.g. CYP2D6*10/*10, *17, *4 and *9 and *9/*9) that predicted an intermediate metabolizer phenotype. Another subject carried the defective CYP2D6*17 allele and six carried the defective CYP2D6*9 allele. Both these alleles have not been reported in other earlier Chinese studies. CONCLUSION This study revealed that, in terms of CYP2D6 polymorphism, Malaysian Chinese were a heterogeneous group of people. Although sharing some similarities with other Orientals, they also seemed to have some notable differences. The alleles CYP2D6*4, *5, *9, *10 and *17 were all detected. CYP2D6*3 was however absent.
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Affiliation(s)
- R Ismail
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.
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Nikoloff D, Shim JC, Fairchild M, Patten N, Fijal BA, Koch WH, MacPherson A, Flockhart D, Yoon YR, Yoon JS, Kim YH, Shin JG. Association between CYP2D6 genotype and tardive dyskinesia in Korean schizophrenics. THE PHARMACOGENOMICS JOURNAL 2003; 2:400-7. [PMID: 12629505 DOI: 10.1038/sj.tpj.6500138] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2002] [Revised: 07/08/2002] [Accepted: 07/09/2002] [Indexed: 11/09/2022]
Abstract
The CYP2D6 gene codes for human cytochrome P450 2D6 enzyme, which is responsible for the metabolism of many psychiatric drugs. In schizophrenic patients treated with neuroleptics, decreased or loss of function CYP2D6 alleles may contribute to the development of tardive dyskinesia (TD), a movement disorder that frequently occurs with chronic neuroleptic treatment. The goal of this study was to determine whether the occurrence of TD is associated with CYP2D6 genotype in a cohort of Korean schizophrenics by employing a CYP450 GeneChip((R)) oligonucleotide microarray and PCR assays to screen for 19 CYP2D6 alleles. Our results revealed that males with at least one decreased or loss of function allele have a moderately greater chance of developing TD than males with only wild-type alleles. Female schizophrenics did not have a significantly greater chance of developing TD. Our results demonstrate the utility of CYP2D6 microarrays to assess genotype status in this Korean cohort.
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Affiliation(s)
- D Nikoloff
- Roche Molecular Systems, Pharmacogenetics Department, Alameda, CA, USA
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Gaedigk A, Ryder DL, Bradford LD, Leeder JS. CYP2D6 poor metabolizer status can be ruled out by a single genotyping assay for the -1584G promoter polymorphism. Clin Chem 2003; 49:1008-11. [PMID: 12766015 DOI: 10.1373/49.6.1008] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Andrea Gaedigk
- Division of Developmental Pharmacology and Medical Toxicology, The Children's Mercy Hospital and Clinics, Kansas City, MO 64108, USA.
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46
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Dalén P, Dahl ML, Roh HK, Tybring G, Eichelbaum M, Wilkinson GR, Bertilsson L. Disposition of debrisoquine and nortriptyline in Korean subjects in relation to CYP2D6 genotypes, and comparison with Caucasians. Br J Clin Pharmacol 2003; 55:630-4. [PMID: 12814461 PMCID: PMC1884261 DOI: 10.1046/j.1365-2125.2003.01804.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To study the influence of the CYP2D6*10 allele on the disposition of debrisoquine and nortriptyline. METHODS The pharmacokinetics of debrisoquine and nortriptyline and their main metabolites were determined in ten Koreans with the CYP2D6*1/*1 (n = 5) and CYP2D6*1/*10 (n = 5) genotypes after single oral doses of 20 mg debrisoquine and 25 mg nortriptyline, respectively. The data were compared with previously published findings from 21 Caucasians with 0, one, two, three, four or 13 functional CYP2D6 genes. RESULTS The AUC0-8 of 4-hydroxydebrisoquine was significantly lower in Koreans with CYP2D6*1/*10 genotype compared with CYP2D6*1/*1[95% confidence interval (CI) for the ratio between means 1.17, 1.85]. No other genotype-related differences were found in the plasma kinetics of nortriptyline and debrisoquine, or their hydroxy metabolites. The AUCnortriptyline/AUC10-hydroxynortriptyline ratio did not differ between the *1/*1 and *1/*10 genotype groups (95% CI for the ratio of means 0.60, 1.26). Similarly, there was no difference between these genotypes with respect to the AUCdebrisoquine/AUC4-hydroxydebrisoquine ratio (95% CI for the ratio of mean values 0.38, 1.46). Both Korean genotype groups had similar AUCs and parent compound/metabolite AUC ratios of debrisoquine and nortriptyline to Caucasians with two functional CYP2D6 genes. CONCLUSIONS Heterozygosity for CYP2D6*10 decreases the CYP2D6-dependent elimination of nortriptyline and debrisoquine to only a limited degree. Further studies in subjects homozygous for CYP2D6*10 are required to elucidate fully the pharmacokinetic consequences of this CYP2D6 genotype in Orientals.
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Affiliation(s)
- P Dalén
- Department of Medical Laboratory Sciences & Technology, Division of Clinical Pharmacology, Karolinska Institutet, Huddinge University Hospital, Sweden
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Kim MK, Cho JY, Lim HS, Hong KS, Chung JY, Bae KS, Oh DS, Shin SG, Lee SH, Lee DH, Min B, Jang IJ. Effect of the CYP2D6 genotype on the pharmacokinetics of tropisetron in healthy Korean subjects. Eur J Clin Pharmacol 2003; 59:111-6. [PMID: 12728290 DOI: 10.1007/s00228-003-0595-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2002] [Accepted: 03/19/2003] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To evaluate the effect of the CYP2D6 genotype on the pharmacokinetics of tropisetron in healthy Korean subjects. METHODS A single 5-mg capsule of tropisetron was administered orally to 13 healthy subjects. Plasma concentrations were determined by validated HPLC procedures and data were analyzed by using noncompartmental linear PK methods. Four alleles, CYP2D6*1, CYP2D6*2 x2, CYP2D6*5, and CYP2D6*10, were identified by PCR. RESULTS Thirteen subjects, consisting of two homozygous carriers of the wild type allele ( *1/*1), four heterozygous carriers of poor metabolizer (PM)-associated allele (* 1/*10), six homozygous carriers of PM-associated alleles (four with *10/*10 and two with *5/*10), and one carrier of a duplicated allele *1/*2 x2. All tested pharmacokinetic parameters (AUC(inf), AUC(inf)(NL70), Cmax, Cmax(NL70), T(1/2), and Tec) were significantly different among four different genotypic groups. The mean AUCs of carriers with the heterozygous PM-associated allele and the homozygous PM-associated allele were 1.9- and 6.8-higher than those of carriers with the wild type allele, respectively. In contrast, the mean AUC of carriers with a duplicated allele was 0.5-fold lower than that of those carriers with the wild type allele. CONCLUSION The presence of CYP2D6*5, CYP2D6*10, and CYP2D6*2 x2 has an important impact on the pharmacokinetics of tropisetron, which may influence clinical response to tropisetron therapy.
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Affiliation(s)
- Myo-Kyoung Kim
- Department of Pharmacology, College of Medicine, 28 Yongon-Dong, Chongno-Gu, 110-799, Seoul, South Korea
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Ohara K, Tanabu S, Ishibashi K, Ikemoto K, Yoshida K, Shibuya H. Effects of age and the CYP2D6*10 allele on the plasma haloperidol concentration/dose ratio. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:347-50. [PMID: 12691769 DOI: 10.1016/s0278-5846(02)00314-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The authors studied the effect of aging and the CYP2D6*10 polymorphism on the plasma haloperidol (HAL) concentration after chronic administration of HAL. Subjects were 110 Japanese patients (66 male) treated orally with HAL. Venous blood was obtained from each patient for determination of the HAL concentration/dose (C/D) ratio (the plasma concentration of HAL divided by the daily dose of HAL per kilogram body weight) and for CYP2D6 genotyping. Overall, there was a significant linear correlation between the HAL C/D ratio and age. In subgroup analyses, the correlation was significant for patients with non-2D6*10 homozygous genotypes, but not for those with the 2D6*10 homozygous genotype. Overall, the HAL C/D ratio was significantly higher in older subjects (at least 50 years old) than younger ones (less than 50 years old). The ratio was significantly higher in older than in younger subjects for patients with non-2D6*10 homozygous genotypes, but not for those with the 2D6*10 homozygous genotype. Our results indicate that the effect of age on the HAL C/D ratio depends upon the CYP2D6*10 genotype. Because there are racial differences in the CYP2D6 genotype, further studies should investigate age effects on the HAL C/D ratio in different patient populations.
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Affiliation(s)
- Koichi Ohara
- Clinical Research Institute, National Minami Hanamaki Hospital, 500 Suwa, Hanamaki, Iwate 025-0033, Japan.
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Shimizu T, Ochiai H, Asell F, Yokono Y, Kikuchi Y, Nitta M, Hama Y, Yamaguchi S, Hashimoto M, Taki K, Nakata K, Aida Y, Ohashi A, Ozawa N. Bioinformatics Research on Inter-racial Difference in Drug Metabolism II. Analysis on Relationship between Enzyme Activities of CYP2D6 and CYP2C19 and their Relevant Genotypes. Drug Metab Pharmacokinet 2003; 18:71-8. [PMID: 15618720 DOI: 10.2133/dmpk.18.71] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enzyme activities of CYP2D6 and CYP2C19 show a genetic polymorphism, and the frequency of poor metabolizers (PMs) on these enzymes depends on races. We have analyzed frequencies of mutant alleles and PMs based on the published data in previous study (Shimizu, T. et al.: Bioinformatics research on inter-racial difference in drug metabolism, I. Analysis on frequencies of mutant alleles and poor metabolizers on CYP2D6 and CYP2C19.). The study shows that there were racial differences in the frequencies of each mutant allele and PMs. In the present study, the correlation between genotypes and drug-metabolizing enzyme activities was investigated. The result showed that enzyme activities varied according to the genotypes of subjects even in the same race. On the other hand, if subjects had the same genotypes, almost no racial differences were observed in drug-metabolizing enzyme activities. From these results, it was supposed that the racial differences in activities of these enzymes could be explained by the differences in distribution of genotypes. It would be possible to explain the racial differences in drug-metabolizing enzyme activities based on the differences on individual pharmacogenetic background information, not merely by comparison of frameworks such as races and nations.
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Shimizu T, Ochiai H, Asell F, Shimizu H, Saitoh R, Hama Y, Katada J, Hashimoto M, Matsui H, Taki K, Kaminuma T, Yamamoto M, Aida Y, Ohashi A, Ozawa N. Bioinformatics Research on Inter-racial Difference in Drug Metabolism I. Analysis on Frequencies of Mutant Alleles and Poor Metabolizers on CYP2D6 and CYP2C19. Drug Metab Pharmacokinet 2003; 18:48-70. [PMID: 15618719 DOI: 10.2133/dmpk.18.48] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enzyme activities of CYP2D6 and CYP2C19 show a genetic polymorphism, and the frequency of poor metabolizers (PMs) on these enzymes depends on races. In the present study, the frequencies of mutant alleles and PMs in each race were analyzed based on information from published studies, considering the genetic polymorphisms of CYP2D6 and CYP2C19 as the causal factors of racial and inter-individual differences in pharmacokinetics. As a result, it was shown that there were racial differences in the frequencies of each mutant allele and PMs. The frequencies of PMs on CYP2D6 are 1.9% of Asians and 7.7% of Caucasians, and those of PMs on CYP2C19 are 15.8% of Asians and 2.2% of Caucasians. Based on the results, it was suggested that there would be racial differences in the frequencies of PM subjects whose blood concentrations might be higher for drugs metabolized by these enzymes. Additionally, it was suggested that enzyme activities would vary according to the number of functional alleles even in subjects judged to be extensive metabolizers (EMs). In the bridging study, genetic information regarding CYP2D6 and CYP2C19 of the subjects will help extrapolate foreign clinical data to a domestic population.
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