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Hung KKC, Lam RPK, Lee HKH, Choi YF, Tenney J, Zuo Z, Chong MKC, Hui TSI, Wong TK, Yiu TY, Chan SY, Mok CPY, Leung LY, Mak WK, Sun DTF, Cheng CH, Graham CA. Comparison of diclofenac with tramadol, tizanidine or placebo in the treatment of acute low back pain and sciatica: multi-center randomized controlled trial. Postgrad Med J 2024:qgae052. [PMID: 38679808 DOI: 10.1093/postmj/qgae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/16/2024] [Accepted: 03/25/2024] [Indexed: 05/01/2024]
Abstract
BACKGROUND Low back pain (LBP) is a leading cause of disability worldwide and has posed numerous health and socioeconomic challenges. This study compared whether nonsteroidal anti-inflammatory drugs (NSAIDs) in combination with tramadol, tizanidine or placebo would be the best treatment regime to improve the Roland Morris Disability Questionnaire (RMDQ) scores at 1 week. METHODS This was a multi-center, double-blind, randomized, and placebo-controlled trial including adult patients with acute LBP and sciatica in three emergency departments in Hong Kong. Patients were randomized to the receive tramadol 50 mg, tizanidine 2 mg, or placebo every 6 hours for 2 weeks in a 1:1:1 ratio. The RMDQ and other secondary outcomes were measured at baseline, Day 2, 7, 14, 21, and 28. Data were analyzed on an intention to treat basis. Crude and adjusted mean differences in the changes of RMDQ and NRS scores from baseline to Day 7 between tizanidine/tramadol and placebo were determined with 95% confidence intervals. RESULTS Two hundred and ninety-one patients were analyzed with the mean age of 47.4 years and 57.7% were male. The primary outcome of mean difference in RMDQs on Day 7 (compared with baseline) was non-significant for tizanidine compared with placebo (adjusted mean difference - 0.56, 95% CI -2.48 to 1.37) and tramadol compared with placebo (adjusted mean difference - 0.85, 95% CI -2.80 to 1.10). Only 23.7% were fully compliant to the treatment allocated. Complier Average Causal Effect analysis also showed no difference in the primary outcome for the tizanidine and tramadol versus placebo. CONCLUSION Among patients with acute LBP and sciatica presenting to the ED, adding tramadol or tizanidine to diclofenac did not improve functional recovery.
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Affiliation(s)
- Kevin K C Hung
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
- Accident & Emergency Department, Prince of Wales Hospital, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Rex P K Lam
- Department of Emergency Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, G06, G/F, University of Hong Kong the Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong SAR, China, Hong Kong
| | - Herman K H Lee
- Accident & Emergency Department, United Christian Hospital, 130 Hip Wo St, Kwun Tong, Hong Kong SAR, Hong Kong
| | - Yu Fai Choi
- Accident & Emergency Department, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Chai Wan, Hong Kong, Hong Kong
| | - Justin Tenney
- School of Pharmacy, The Chinese University of Hong Kong, 8th Floor, Lo Kwee-Seong Integrated Biomedical Sciences Building Area 39, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, Hong Kong
- Pharmacy Department, Canberra Hospital, Yamba Drive Garran ACT 2605, Canberra, Australia
| | - Zhong Zuo
- School of Pharmacy, The Chinese University of Hong Kong, 8th Floor, Lo Kwee-Seong Integrated Biomedical Sciences Building Area 39, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, Hong Kong
| | - Marc K C Chong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Theresa S I Hui
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Tak Kan Wong
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Tsz Ying Yiu
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Suet Yi Chan
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Catherine P Y Mok
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Ling Yan Leung
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Wai Kit Mak
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - David T F Sun
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Chi Hung Cheng
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
- Accident & Emergency Department, Prince of Wales Hospital, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
| | - Colin A Graham
- Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
- Accident & Emergency Department, Prince of Wales Hospital, 2/F, Main Clinical Block and Trauma Centre, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, Hong Kong
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Cheng W, Lam RPK, Chan CK. Factors associated with seizure in tramadol overdose: a 12-year retrospective study in Hong Kong. Clin Toxicol (Phila) 2022; 60:1220-1226. [DOI: 10.1080/15563650.2022.2124919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Wendy Cheng
- Accident & Emergency Department, Queen Elizabeth Hospital, Hospital Authority, Hong Kong, S.A.R, China
| | - Rex Pui Kin Lam
- Department of Emergency Medicine, School of Clinical Medicine, The University of Hong Kong, Hong Kong, S.A.R, China
| | - Chi Keung Chan
- Hong Kong Poison Information Centre, Hospital Authority, Hong Kong, S.A.R, China
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Bakar NS. Pharmacogenetics of common SNP affecting drug metabolizing enzymes: comparison of allele frequencies between European and Malaysian/Singaporean. Drug Metab Pers Ther 2021; 36:173-181. [PMID: 34412170 DOI: 10.1515/dmpt-2020-0153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 01/03/2021] [Indexed: 11/15/2022]
Abstract
Compared to Europe, data on genetic variation in genes transcribing drug metabolizing enzymes among Asian is limited due to ethnic diversity. Here we compare frequencies for clinically relevant single nucleotide polymorphism (SNP) commonly observed in drug metabolizing enzymes between European and Malaysian/Singaporean. Minor allele frequencies (MAF) for the indicated SNPs for European, South Asian and East Asian populations were obtained from the NCBI website (https://www.ncbi.nlm.nih.gov/snp). The SNP prevalence among Malaysian/Singaporean was characterized from gene association studies. Generally, some SNPs in CYP2D6 and CYP2C19 do not show good agreement between the two populations as to the MAF value obtained. CYP2D6*4 tends to be more common among European, whereas CYP2D6*10 is more common in Malays and Chinese among Singaporean. Regardless of different phenotype, MAF of CYP2D6*4 for Indians is similar to that seen by the European. Singaporeans show smaller MAF for CYP2C19*17 but higher CYP2C19*2 frequencies as opposed to European ones. Following growing attention to the contribution of CYP3A4/5, N-acetyltransferases (NAT2), thiopurine methyltransferase (TPMT) and uridine diphosphate glucuronosyltransferases (UGT)2B7 in predicting drug response across Europe, there are limited pharmacogenetics (PGx) studies examining the gene-drug interaction among Malaysian/Singaporean. To better understand the heterogeneity of the drug response, PGx studies for the abovementioned enzymes between ethnics in Malaysian/Singaporean should be identified.
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Affiliation(s)
- Nur Salwani Bakar
- School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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4
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Bakar NS. Pharmacogenetics of common SNP affecting drug metabolizing enzymes: comparison of allele frequencies between European and Malaysian/Singaporean. Drug Metab Pers Ther 2021; 0:dmdi-2020-0153. [PMID: 33735954 DOI: 10.1515/dmdi-2020-0153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 01/03/2021] [Indexed: 11/15/2022]
Abstract
Compared to Europe, data on genetic variation in genes transcribing drug metabolizing enzymes among Asian is limited due to ethnic diversity. Here we compare frequencies for clinically relevant single nucleotide polymorphism (SNP) commonly observed in drug metabolizing enzymes between European and Malaysian/Singaporean. Minor allele frequencies (MAF) for the indicated SNPs for European, South Asian and East Asian populations were obtained from the NCBI website (https://www.ncbi.nlm.nih.gov/snp). The SNP prevalence among Malaysian/Singaporean was characterized from gene association studies. Generally, some SNPs in CYP2D6 and CYP2C19 do not show good agreement between the two populations as to the MAF value obtained. CYP2D6*4 tends to be more common among European, whereas CYP2D6*10 is more common in Malays and Chinese among Singaporean. Regardless of different phenotype, MAF of CYP2D6*4 for Indians is similar to that seen by the European. Singaporeans show smaller MAF for CYP2C19*17 but higher CYP2C19*2 frequencies as opposed to European ones. Following growing attention to the contribution of CYP3A4/5, N-acetyltransferases (NAT2), thiopurine methyltransferase (TPMT) and uridine diphosphate glucuronosyltransferases (UGT)2B7 in predicting drug response across Europe, there are limited pharmacogenetics (PGx) studies examining the gene-drug interaction among Malaysian/Singaporean. To better understand the heterogeneity of the drug response, PGx studies for the abovementioned enzymes between ethnics in Malaysian/Singaporean should be identified.
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Affiliation(s)
- Nur Salwani Bakar
- School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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5
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Chan W, Li MS, Sundaram SK, Tomlinson B, Cheung PY, Tzang CH. CYP2D6 allele frequencies, copy number variants, and tandems in the population of Hong Kong. J Clin Lab Anal 2018; 33:e22634. [PMID: 30069923 DOI: 10.1002/jcla.22634] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/05/2018] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND CYP2D6 plays a crucial role in drug metabolism of several drugs. It is known to be highly polymorphic with enzymatic activity ranging from poor to ultrarapid metabolic rates. While the frequencies of CYP2D6 alleles are generally known in different Asian populations, data on frequencies of the copy number variations (CNV) and tandems in CYP2D6 in which they occur are less well studied in these populations. METHODS A cohort of 800 consecutive, unrelated individuals were referred to Prenetics Limited (Prenetics) iGenes test by physicians in Hong Kong as part of their care with informed consent. These clinical samples were deidentified prior to further analysis. Genotyping and copy number determination of CYP2D6 were performed using target specific TaqMan® SNP genotyping and copy number assays. The phenotypes of CYP2D6 were predicted based on its genotypes and is dependent on the biallelic expression of alleles. RESULTS Among the Asian group (n = 735, 92%), the observed frequency of CYP2D6*36-*10 tandems was 34.1%. We also identified duplication of CYP2D6 alleles in 86 (11.7%) individuals of the study cohort. The frequency of all CYP2D6 duplicated alleles was 154 (10.5%) while only 28 (1.9%) of the duplications were of functional alleles (ie CYP2D6*1 and CYP2D6*2). CONCLUSION The present study provides a comprehensive analysis on the occurrences of CNV and tandems of the CYP2D6 gene in the Hong Kong population. The results contribute to the overall knowledge of pharmacogenomics and may accelerate the implementation of precision medicine in Asia.
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Affiliation(s)
- Wing Chan
- Prenetics Limited, Hong Kong City, Hong Kong
| | - Man S Li
- Prenetics Limited, Hong Kong City, Hong Kong
| | | | - Brian Tomlinson
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong City, Hong Kong
| | | | - Chi H Tzang
- Prenetics Limited, Hong Kong City, Hong Kong
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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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Dandara C, Swart M, Mpeta B, Wonkam A, Masimirembwa C. Cytochrome P450 pharmacogenetics in African populations: implications for public health. Expert Opin Drug Metab Toxicol 2014; 10:769-85. [PMID: 24588448 DOI: 10.1517/17425255.2014.894020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Africa harbors a disproportionate burden of disease when taking into account the triple challenge caused by HIV/AIDS, tuberculosis (TB) and malaria, against a backdrop of an increasing burden of noncommunicable diseases. More than 80% of therapeutic drugs used in the management of these diseases/conditions are metabolized by CYP enzymes that exhibit genetic polymorphisms. AREAS COVERED There is variability in the expression and activities of CYPs resulting in interindividual differences in the response to standard doses of therapeutic drugs, due to genetic polymorphisms, which exhibit both quantitative and qualitative differences between racial and between ethnic groups. The review aims to evaluate the implications of the genetic variation in CYPs on the public health of Africans. The CYPs reviewed here metabolize most of the commonly used therapeutic drugs and include CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4 and 3A5. Allele frequencies are compared between African ethnic groups and among populations of African, Asian and European origin. Data are obtained from our own studies and literature. EXPERT OPINION The variability in the pattern of genetic variation between populations translates into differences in drug response. Understanding CYP variability improves rational drug use and has public health significance.
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Affiliation(s)
- Collet Dandara
- University of Cape Town, Faculty of Health Sciences, Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences , Anzio Road Observatory, 7925, Cape Town , South Africa +27 21 406 6506 ;
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Chen B, Xu Y, Jiang T, Feng R, Sun J, Zhang W, Yang W, Li J, Adeniyi O, Chen H. Estimation of CYP2D6*10 genotypes on citalopram disposition in Chinese subjects by population pharmacokinetic assay. J Clin Pharm Ther 2013; 38:504-11. [PMID: 23981149 DOI: 10.1111/jcpt.12029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 10/25/2012] [Indexed: 11/26/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE There is great interindividual variability in citalopram (CIT) pharmacokinetics. We attempted to establish a population pharmacokinetic (PPK) model of CIT in Chinese healthy subjects, to evaluate the effect of genetic polymorphism on CIT pharmacokinetics and to compare the PPK and non-compartmental (NCA) assays in the estimation of CIT bioequivalence. METHODS Blood samples of 23 healthy subjects were collected after administration of CIT; plasma concentration of CIT was analysed using LC/MS-MS. CYP2C19 and CYP2D6*10 genotypes were determined. PPK model was established by using nonlinear mixed-effect modelling (NONMEM). The model was evaluated using goodness-of-fit plots and relative error measurements. Bioequivalence of CIT was evaluated by both PPK and NCA method. RESULTS AND DISCUSSION The estimated population absorption rate constant (ka ), clearance (CL/F) and volume of distribution (Vd/F) in Chinese healthy subjects are 0.64 L/h, 12.7 L/h and 705 L, respectively. Different CYP2C19 and CYP2D6 genotypes have impacts on CIT pharmacokinetics. There is about 5.5% decrement of CL/F for each CYP2C19*2 or CYP2D6*10 allele. The 90% confidence interval of CIT bioavailability obtained from NCA and PPK model were 96.4-105.4% and 92.5-103.4%, respectively. WHAT IS NEW AND CONCLUSION The PPK of CIT is best characterized by a one-compartment disposition model with first-order absorption. CYP2C19 and CYP2D6 genotypes have impacts on the CL/F of CIT. Bioequivalence of CIT can be estimated by both NCA and PPK model.
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Affiliation(s)
- B Chen
- Department of Pharmacy, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
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Baclig MO, Predicala RZ, Mapua CA, Lozano-Kühne JP, Daroy MLG, Natividad FF, Javier FO. Allelic and genotype frequencies of catechol-O-methyltransferase (Val158Met) and CYP2D6*10 (Pro34Ser) single nucleotide polymorphisms in the Philippines. INTERNATIONAL JOURNAL OF MOLECULAR EPIDEMIOLOGY AND GENETICS 2012; 3:115-121. [PMID: 22724048 PMCID: PMC3376921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 04/23/2012] [Indexed: 06/01/2023]
Abstract
A hospital-based cross-sectional study was conducted to determine the allelic and genotype frequencies in the genes encoding for catechol-O-methyltransferase and CYP2D6*10 among healthy volunteers and patients clinically diagnosed with cancer pain. PCR-RFLP was used to identify COMT and CYP2D6*10 genotypes. Allelic frequencies among healthy volunteer Filipinos were 0.83 and 0.17 for the COMT Val and COMT Met alleles, respectively. Calculated frequencies in Hardy-Weinberg equilibrium (HWE) were 73% for COMT Val/Val, 26% for COMT Val/Met, and 1% for COMT Met/Met genotype. For CYP2D6*10, allelic frequencies in HWE among volunteers were 0.46 for the C allele and 0.54 for the T allele. Twenty percent were identified as homozygous for the wild-type C/C genotype, 56% were identified as heterozygous for the C/T genotype, and 24% were identified as homozygous for the T/T variant genotype. No significant differences in COMT and CYP2D6*10 allele frequencies between cancer patients and healthy volunteers were noted. Our data demonstrated that the allele frequencies of COMT and CYP2D6*10 in the Filipino healthy volunteers were similar with other Asians but markedly different from Caucasian populations.
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Affiliation(s)
- Michael O Baclig
- Research and Biotechnology Division, St. Luke’s Medical Center, Quezon City, Philippines.
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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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Wang HH, Liao YW, Chiang HL, Wu JY, Chen YT. Novel DNA sequence variations of cytochrome P450 genes in the Han Chinese population. Pharmacogenomics 2009; 10:359-74. [DOI: 10.2217/14622416.10.3.359] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: Cytochrome P450 is an important monooxygenase responsible for the metabolism of a large variety of structurally diverse compounds. The aim of this study was to systematically investigate the DNA sequence variations in 14 cytochrome P450 genes relevant to drug metabolism in the Han Chinese population. Materials & methods: We sequenced these 14 genes in 23 subjects and determined the allele frequencies. Results: We identified a total of 312 genetic variants, which included 80 (25.6%) novel variants. These novel variants included 67 noncoding variants, four synonymous and nine nonsynonymous variants. Among these variants, an 11-nucleotide insertion in the 3´-flanking site of intron 6 in CYP2E1 (c.968-77_-76insGATGGGTGGAT) had the highest allele frequency of 0.565. A total of 16 of these novel variants were predicted to have potential functional consequences; however, among them only c.-1299T>A in CYP2C18 and c.-498C>A in CYP2D6 reached a frequency of 4.9%. Conclusions: This study establishes a genetic database of cytochrome P450 genes in the Han Chinese population and suggests further genetic diversity throughout this important gene family.
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Affiliation(s)
- Hui-Hung Wang
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Yie-Wen Liao
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Hung-Lun Chiang
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Jer-Yuarn Wu
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
- China Medical College Hospital, Taiwan
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
- Duke University Medical Center, NC, USA
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13
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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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14
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Cai WM, Chen B, Zhang WX. Frequency of CYP2D6*10 and *14 alleles and their influence on the metabolic activity of CYP2D6 in a healthy Chinese population. Clin Pharmacol Ther 2007; 81:95-8. [PMID: 17186005 DOI: 10.1038/sj.clpt.6100015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To study the frequency of CYP2D6(*)10 and (*)14 alleles in a healthy Chinese population, and the influence of these two alleles on the metabolic activity of CYP2D6. CYP2D6(*)10 and (*)14 genotypes of 295 healthy Chinese subjects were determined using a tetra-primer method and allele-specific amplification. CYP2D6 phenotypes of 131 subjects were determined using dextramethorphan as probe drug. There were 10 subjects with a (*)14 allele, including one homozygous for (*)14. The gene frequency of (*)10 and (*)14 alleles were 55.8 and 1.8%, respectively. The metabolic ratio (MR) of dextramethorphan in 131 subjects was 0.032+/-0.106. The MR of (*)1/(*)1, (*)1/(*)10, (*)10/(*)10, (*)1/(*)14, (*)10/(*)14, and (*)14/(*)14 groups were 0.007+/-0.012, 0.009+/-0.010, 0.042+/-0.029, 0.093, 0.11, and 1.186, respectively. The MR of subjects with (*)14 allele was higher than those of (*)1/(*)1, (*)1/(*)10, or (*)10/(*)10 groups (P<0.001). The CYP2D6(*)10 and (*)14 alleles have substantial impact on the metabolic activity of CYP2D6, and the CYP2D6(*)14 allele may be the cause of the poor metabolizer phenotype in Chinese subjects.
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Affiliation(s)
- W M Cai
- Department of Pharmacy, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, People's Republic of China.
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15
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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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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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Ji L, Pan S, Marti-Jaun J, Hänseler E, Rentsch K, Hersberger M. Single-Step Assays to Analyze CYP2D6 Gene Polymorphisms in Asians: Allele Frequencies and a Novel *14B Allele in Mainland Chinese. Clin Chem 2002. [DOI: 10.1093/clinchem/48.7.983] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractBackground: Cytochrome P450-dependent monooxygenase 2D6 (CYP2D6) activity can be estimated by investigating the metabolism of model drugs or by genotyping the most common CYP2D6 alleles. For Caucasians, the CYP2D6 allele frequencies are well investigated, and single-step assays are available for genotyping, whereas allele analysis in mainland Chinese is limited.Methods: Two tetra-primer assays and one allele-specific amplification assay were developed to easily genotype the CYP2D6 alleles *8, *10, and *14 previously detected in Asians. Applying these assays in combination with established single-tube assays, we analyzed 223 DNA samples from Chinese volunteers for the CYP2D6 alleles *3, *4, *5, *6, *8, *10, and *14 and for duplication of CYP2D6.Results: Six different alleles were detected in mainland Chinese. The most frequent mutant allele was the intermediate metabolizer allele, CYP2D6*10, with a prevalence of 51.3%, followed by the poor metabolizer alleles CYP2D6*5 (7.2%) and a novel variant of CYP2D6*14. This novel *14B allele (2.0%) differs from the *14 allele by the absence of the C188T substitution and by the additional G1749C substitution. Furthermore, six duplication alleles of CYP2D6 were detected, including one duplication of the *10 allele (*10X2).Conclusions: The CYP2D6 allele frequencies in mainland Chinese shows some genetic diversity compared with Chinese from other regions: a novel *14B allele, a slightly higher frequency of the *5 allele, and a slightly lower frequency of the *10 allele than in most other Chinese populations.
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Affiliation(s)
- Ling Ji
- Institute of Clinical Chemistry, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
- Clinical Medical Laboratory, Union Hospital Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Republic of China
| | - Shixiu Pan
- Clinical Medical Laboratory, Union Hospital Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Republic of China
| | - Jacqueline Marti-Jaun
- Institute of Clinical Chemistry, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
| | - Edgar Hänseler
- Institute of Clinical Chemistry, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
| | - Katharina Rentsch
- Institute of Clinical Chemistry, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
| | - Martin Hersberger
- Institute of Clinical Chemistry, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
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Teh LK, Ismail R, Yusoff R, Hussein A, Isa MN, Rahman AR. Heterogeneity of the CYP2D6 gene among Malays in Malaysia. J Clin Pharm Ther 2001; 26:205-11. [PMID: 11422605 DOI: 10.1046/j.1365-2710.2001.00347.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Although Malays shared an origin with Chinese, their evolution saw substantial divergences. Phenotyping studies suggested that they differed in CYP2D6 polymorphism, with higher PM prevalence but lesser right-shift for debrisoquine MRs. OBJECTIVE To study the genotype distribution of CYP2D6 among the Malays in Malaysia. METHOD We obtained DNA from 107 Malays and used PCR to determine common CYP2D6 alleles. RESULT CYP2D6*1 occurred at a frequency of 36.0%, duplicated gene, 0.93%, CYP2D6*4, 2.8%, CYP2D6*5, 5.1%, CYP2D6*9, 3.3%, CYP2D6*10, 49.5% and CYP2D6*17, 0.5%. The findings of CYP2D6*17 and CYP2D6*9 were novel for Asia. The frequency for CYP2D6*10 was lower than in other Asian races. The most frequent genotypes were CYP2D6*1/*10 at 39.3%. Two subjects had genotypes that predicted PM phenotype, 35% showed genotypes that predicted intermediate metabolizers and one subject had a genotype that predicted ultra-rapid metabolism. CONCLUSION The genetic polymorphism of CYP2D6 in Malays is different from Chinese and Far Eastern races. They may be intermediate between East Asians and Caucasians in CYP2D6 activity. Further study in relation to the evolution of races and disease prevalence may help to identify the contributions of the polymorphism in alleged susceptibility to diseases apart from delineating its contributions to ethnic differences in the pharmacology of CYP2D6 drugs.
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Affiliation(s)
- L K Teh
- Department of Pharmacy, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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19
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Abstract
BACKGROUND Although they originated from China, Malays have undergone a lot of intermarriages. A study suggested that CYP2D6 poor metabolism (PM) phenotype was more common in Malays compared to Chinese. CYP2D6 is highly polymorphic and is involved in the metabolism of many drugs and has been implicated in some environmentally-induced diseases. It is therefore useful to further study this polymorphism in Malays. OBJECTIVE To study debrisoquine metabolism phenotypes in healthy Malay volunteers. METHOD We administered debrisoquine to 51 Malays and used HPLC to measure urinary debrisoquine and 4-hydroxy debrisoquine to calculate debrisoquine metabolic ratios (MR). RESULTS Debrisoquine MR varied widely and with probit analysis we were able to identify population subsets. Although the frequency distribution for the MR showed a right shift, the shift was less than that reported for the Chinese population. We also found 2 poor metabolizers and one ultra rapid metaboliser in the population. CONCLUSION The genetic polymorphism of debrisoquine in Malays differs from that in the Chinese. Both their PM prevalence and their MR distribution suggest that they are intermediate between Europeans and Chinese in relation to this polymorphism. Studies to compare CYP2D6 genotypes between them and related races would be useful to further define these differences.
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Affiliation(s)
- R Ismail
- Department of Pharmacology, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan, Malaysia.
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20
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Aitchison KJ, Jordan BD, Sharma T. The relevance of ethnic influences on pharmacogenetics to the treatment of psychosis. DRUG METABOLISM AND DRUG INTERACTIONS 2000; 16:15-38. [PMID: 10820581 DOI: 10.1515/dmdi.2000.16.1.15] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Interethnic variation amongst the drug metabolising enzymes relevant to the treatment of psychosis is reviewed. The frequency of genetically determined variants at the extremes of enzyme activity is seen to vary considerably between different ethnic groups; in addition, a shift in the frequency distribution giving an overall lower population mean activity may occur. The role of dietary and other environmental influences in the generation of interethnic variation in cytochrome activity is also discussed. Clinical studies pertinent to this variation are reviewed. It is suggested that the reason for conflicting data from some clinical studies is the existence of overlapping substrate specificity, so that one cytochrome is able to substitute for another. Individuals deficient for more than one cytochrome would be likely to show much more pronounced clinical effects than those showing single cytochrome deficiency.
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Affiliation(s)
- K J Aitchison
- Section of Clinical Neuropharmacology, Institute of Psychiatry, London, UK
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21
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Garcia-Barceló M, Chow LY, Chiu HFK, Wing YK, Lee DTS, Lam KL, Waye MMY. Genetic Analysis of the CYP2D6 Locus in a Hong Kong Chinese Population. Clin Chem 2000. [DOI: 10.1093/clinchem/46.1.18] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Background: The cytochrome P450 CYP2D6 enzyme debrisoquine 4-hydroxylase metabolizes many different classes of commonly used drugs, such as tricyclic antidepressants and neuroleptics. Genetic polymorphism of the CYP2D6 gene is responsible for pronounced interindividual and interracial differences in the metabolism of these drugs. The CYP2D6*10 allele and its variants are the most frequent alleles found in Orientals, and they are responsible for diminished debrisoquine 4-hydroxylase activity because of the presence of a C188→T mutation in exon 1.
Methods: One hundred nineteen Hong Kong Chinese subjects were genotyped by means of allele-specific PCR, PCR, and restriction enzyme analysis for 10 CYP2D6 alleles (CYP2D6*1, *2, *4D, *5, *8/*14, *10A, *10B, *15, *16, and J9).
Results: CYP2D6*10B was the most prevalent allele, and CYP2D6*10/CYP2D6*10 was the most frequent genotype, representing 46.22% of the population.
Conclusions: There was no significant difference in the prevalence of the alleles analyzed between our study and the Chinese populations genotyped previously. This is the largest study in terms of the number of CYP2D6 alleles analyzed in an Oriental population and the first one conducted in a Hong Kong Chinese population.
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Affiliation(s)
- Mercè Garcia-Barceló
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Lok Yee Chow
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Helen Fung Kum Chiu
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Yun Kowk Wing
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Dominic Tak Shing Lee
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Kwok Lim Lam
- Department of Psychiatry, 11/F Room 134046, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Mary Miu Yee Waye
- Department of Biochemistry, Room 608, 6/F Mong Man Wai Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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22
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Abstract
1. The cytochrome P450 monooxygenases, CYP2D6, CYP2C19, and CYP2C9, display polymorphism. CYP2D6 and CYP2C19 have been studied extensively, and despite their low abundance in the liver, they catalyze the metabolism of many drugs. 2. CYP2D6 has numerous allelic variants, whereas CYP2C19 has only two. Most variants are translated into inactive, truncated protein or fail to express protein. 3. CYP2C9 is expressed as the wild-type enzyme and has two variants, in each of which one amino acid residue has been replaced. 4. The nucleotide base sequences of the cDNAs of the three polymorphic genes and their variants have been determined, and the proteins derived from these genes have been characterized. 5. An absence of CYP2D6 and/or CYP2C19 in an individual produces a poor metabolizer (PM) of drugs that are substrates of these enzymes. 6. When two drugs that are substrates for a polymorphic CYP enzyme are administered concomitantly, each will compete for that enzyme and competitively inhibit the metabolism of the other substrate. This can result in toxicity. 7. Patients can be readily phenotyped or genotyped to determine their CYP2D6 or CYP2C19 enzymatic status. Poor metabolizers (PMs), extensive metabolizers (EMs), and ultrarapid metabolizers (URMs) can be identified. 8. Numerous substrates and inhibitors of CYP2D6, CYP2C19, and CYP2C9 are identified. 9. An individual's diet and age can influence CYP enzyme activity. 10. CYP2D6 polymorphism has been associated with the risk of onset of various illnesses, including cancer, schizophrenia, Parkinson's disease, Alzheimer's disease, and epilepsy.
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Affiliation(s)
- R T Coutts
- Department of Psychiatry, University of Alberta, Edmonton, Canada
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Terao T, Ohmori O, Shinkai T. A puzzling case of seizures and visual hallucinations during clomipramine treatment with a high dose but causing a low serum concentration. Acta Psychiatr Scand 1999; 99:388-90; discussion 390-2. [PMID: 10353456 DOI: 10.1111/j.1600-0447.1999.tb07246.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We present a puzzling case of a 25-year-old depressive man suffering from seizures and visual hallucinations during clomipramine treatment with a high dose but causing a low serum concentration. We examined alleles of cytochrome P450 (CYP) isozymes. It was revealed that he was not an ultrarapid metabolizer for CYP2D6, and that the genotypes were homozygous for CYP2D6J and heterozygous for CYP2C19m1. Throughout the treatment period, his compliance was good. Since he was a smoker, it seems likely that his low clomipramine level was due to smoking-induced CYP1A2 activity. These findings suggest that smoking-induced CYP1A2 activity overcomes the possibly inhibiting effects of homozygosity for CYP2D6J and heterozygosity for CYP2C19m1, and that high-dose clomipramine is not always a direct cause of seizures.
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Affiliation(s)
- T Terao
- Department of Psychiatry, University of Occupational and Environmental Health, Kitakyushu, Japan
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24
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Wormhoudt LW, Commandeur JN, Vermeulen NP. Genetic polymorphisms of human N-acetyltransferase, cytochrome P450, glutathione-S-transferase, and epoxide hydrolase enzymes: relevance to xenobiotic metabolism and toxicity. Crit Rev Toxicol 1999; 29:59-124. [PMID: 10066160 DOI: 10.1080/10408449991349186] [Citation(s) in RCA: 217] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this review, an overview is presented of the current knowledge of genetic polymorphisms of four of the most important enzyme families involved in the metabolism of xenobiotics, that is, the N-acetyltransferase (NAT), cytochrome P450 (P450), glutathione-S-transferase (GST), and microsomal epoxide hydrolase (mEH) enzymes. The emphasis is on two main topics, the molecular genetics of the polymorphisms and the consequences for xenobiotic metabolism and toxicity. Studies are described in which wild-type and mutant alleles of biotransformation enzymes have been expressed in heterologous systems to study the molecular genetics and the metabolism and pharmacological or toxicological effects of xenobiotics. Furthermore, studies are described that have investigated the effects of genetic polymorphisms of biotransformation enzymes on the metabolism of drugs in humans and on the metabolism of genotoxic compounds in vivo as well. The effects of the polymorphisms are highly dependent on the enzyme systems involved and the compounds being metabolized. Several polymorphisms are described that also clearly influence the metabolism and effects of drugs and toxic compounds, in vivo in humans. Future perspectives in studies on genetic polymorphisms of biotransformation enzymes are also discussed. It is concluded that genetic polymorphisms of biotransformation enzymes are in a number of cases a major factor involved in the interindividual variability in xenobiotic metabolism and toxicity. This may lead to interindividual variability in efficacy of drugs and disease susceptibility.
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Affiliation(s)
- L W Wormhoudt
- Leiden Amsterdam Center for Drug Research, Vrije Universiteit, Department of Pharmacochemistry, The Netherlands
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25
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Brannan MD, Reidenberg P, Radwanski E, Shneyer L, Lin CC, Cayen MN, Affrime MB. Loratadine administered concomitantly with erythromycin: pharmacokinetic and electrocardiographic evaluations. Clin Pharmacol Ther 1995; 58:269-78. [PMID: 7554700 DOI: 10.1016/0009-9236(95)90243-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To evaluate the effects of coadministration of loratadine and erythromycin on the pharmacokinetics and electrocardiographic repolarization (QTc) pharmacodynamics of loratadine and its metabolite descarboethoxyloratadine in healthy volunteers. METHODS Twenty-four healthy volunteers were studied in a prospective, double-blind crossover design while confined in a Clinical Research Center. The primary pharmacodynamic end point of the study was the difference between baseline and day 10 mean QTc intervals obtained from surface electrocardiograms. Plasma concentrations of loratadine, descarboethoxyloratadine, and erythromycin were measured on treatment day 10 for pharmacokinetic analysis. Subjects received in random sequence the following three treatments for 10 consecutive days during three separate study periods: 10 mg loratadine every morning plus 500 mg erythromycin stearate every 8 hours, or 10 mg loratadine every morning plus placebo every 8 hours, or placebo every morning plus 500 mg erythromycin stearate. RESULTS Concomitant administration of loratadine and erythromycin was associated with increased plasma concentrations of loratadine (40% increase in area under the plasma concentration-time curve [AUC]) and descarboethoxyloratadine (46% increase in AUC) compared with loratadine alone. Analysis of variance showed no difference between the treatment groups in effect on QTc intervals compared with baseline, and no significant change from baseline was observed. No clinically relevant changes in the safety profile of loratadine were observed, and there were no reports of sedation nor syncope. CONCLUSION Although concomitant administration of loratadine and erythromycin was associated with increased plasma concentrations of loratadine and descarboethoxyloratadine, no clinically relevant changes in the safety profile of loratadine were observed. In this study, 10 mg loratadine administered orally for 10 consecutive days was well tolerated when coadministered with therapeutic doses of erythromycin stearate.
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Affiliation(s)
- M D Brannan
- Schering-Plough Research Institute, Kenilworth, NJ 07033, USA
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