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Performance Verification of CYP2C19 Enzyme Abundance Polymorphism Settings within the Simcyp Simulator v21. Metabolites 2022; 12:metabo12101001. [PMID: 36295903 PMCID: PMC9607610 DOI: 10.3390/metabo12101001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022] Open
Abstract
Physiologically based pharmacokinetic (PBPK) modeling has a number of applications, including assessing drug−drug interactions (DDIs) in polymorphic populations, and should be iteratively refined as science progresses. The Simcyp Simulator is annually updated and version 21 included updates to hepatic and intestinal CYP2C19 enzyme abundance, including addition of intermediate and rapid metabolizer phenotypes and changes to the ultra-rapid metabolizer enzyme abundance, with implications for population clearance and DDI predictions. This work details verification of the updates with sensitive CYP2C19 substrates, omeprazole and lansoprazole, using available clinical data from literature. Multiple assessments were performed, including recovery of areas under the concentration-time curve (AUC) and Cmax from compiled datasets for each drug, recovery of victim DDI ratios with CYP2C19 and/or CYP3A4 inhibition and recovery of relative exposure between phenotypes. Simulated data were within respective acceptance criteria for >80% of omeprazole AUC values, >70% of lansoprazole AUC and Cmax, >60% of AUC and Cmax DDI ratios and >80% of exposure ratios between different phenotypes. Recovery of omeprazole Cmax was lower (>50−70% within 2-fold) and possibly attributed to the variety of formulations used in the clinical dataset. Overall, the results demonstrated that the updated data used to parameterize CYP2C19 phenotypes reasonably described the pharmacokinetics of omeprazole and lansoprazole in genotyped or phenotyped individuals.
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Papp LA, Hancu G, Kelemen H, Tóth G. Chiral separation in the class of proton pump inhibitors by chromatographic and electromigration techniques: An overview. Electrophoresis 2021; 42:1761-1789. [PMID: 34004039 DOI: 10.1002/elps.202100032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/27/2021] [Accepted: 05/05/2021] [Indexed: 11/08/2022]
Abstract
Proton pump inhibitors (PPIs) are benzimidazole-derivative chiral sulfoxides, frequently used in the treatment of gastric hyperacidity-related disorders. Due to their stereoselective metabolism, the eutomeric forms of PPIs can present a more advantageous pharmacokinetic profile by comparison with the distomers or racemates. Moreover, two representatives of the class are used in therapy both as racemates and as pure enantiomers (esomeprazole, dexlansoprazole). A relatively large number of enantioseparation methods employed for the stereoselective determination of PPIs from pharmaceutical, biological, and environmental matrices were published in the past three decades. The purpose of the current overview is to provide a systematic survey of the available chiral separation methods published since the introduction of PPIs in the therapy up to the present. Analytical and bioanalytical methods using different chromatographic and electromigration techniques reported for the enantioseparation of omeprazole, lansoprazole, pantoprazole, rabeprazole, ilaprazole, and tenatoprazole are included. The analytical conditions of the presented methods are summarized in three comprehensive tables, while a critical discussion of the applied techniques, possible mechanism of enantiorecognition, and future perspectives on the topic are also presented.
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Affiliation(s)
- Lajos Attila Papp
- Department of Pharmaceutical Chemistry, "George Emil Palade" University of Medicine, Pharmacy, Sciences and Technology of Târgu Mureș, Romania
| | - Gabriel Hancu
- Department of Pharmaceutical Chemistry, "George Emil Palade" University of Medicine, Pharmacy, Sciences and Technology of Târgu Mureș, Romania
| | - Hajnal Kelemen
- Department of Pharmaceutical Chemistry, "George Emil Palade" University of Medicine, Pharmacy, Sciences and Technology of Târgu Mureș, Romania
| | - Gergő Tóth
- Department of Pharmaceutical Chemistry, Semmelweis University, Budapest, Hungary
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3
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Miftahussurur M, Doohan D, Syam AF, Nusi IA, Subsomwong P, Waskito LA, Maulahela H, Akil F, Uwan WB, Siregar G, Fauzia KA, Rezkitha YAA, Rahman A, Wibawa IDN, Saudale AMJ, Richardo M, Sugihartono T, Chomariyati A, Bramantoro T, Uchida T, Yamaoka Y. CYP2C19 Polymorphisms in Indonesia: Comparison among Ethnicities and the Association with Clinical Outcomes. BIOLOGY 2021; 10:300. [PMID: 33917299 PMCID: PMC8067412 DOI: 10.3390/biology10040300] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 01/06/2023]
Abstract
CYP2C19 polymorphisms are important factors for proton pump inhibitor-based therapy. We examined the CYP2C19 genotypes and analyzed the distribution among ethnicities and clinical outcomes in Indonesia. We employed the polymerase chain reaction-restriction fragment length polymorphism method to determine the CYP2C19 genotypes and evaluated inflammation severity with the updated Sydney system. For CYP2C19*2, 46.4% were the homozygous wild-type allele, 14.5% were the homozygous mutated allele, and 39.2% were the heterozygous allele. For CYP2C19*3, 88.6% were the homozygous wild-type allele, 2.4% were the homozygous mutated allele, and 9.0% were the heterozygous allele. Overall, the prevalence of rapid, intermediate, and poor metabolizers in Indonesia was 38.5, 41.6, and 19.9%, respectively. In the poor metabolizer group, the frequency of allele *2 (78.8%) was higher than the frequency of allele *3 (21.2%). The Papuan had a significantly higher likelihood of possessing poor metabolizers than the Balinese (OR 11.0; P = 0.002). The prevalence of poor metabolizers was lower compared with the rapid and intermediate metabolizers among patients with gastritis and gastroesophageal reflux disease. Intermediate metabolizers had the highest prevalence, followed by rapid metabolizers and poor metabolizers. Dosage adjustment should therefore be considered when administering proton pump inhibitor-based therapy in Indonesia.
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Affiliation(s)
- Muhammad Miftahussurur
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya 60286, Indonesia; (I.A.N.); (T.S.); (A.C.)
- Institute of Tropical Disease, Universitas Airlangga, Surabaya 60115, Indonesia; (D.D.); (L.A.W.); (K.A.F.); (Y.A.A.R.)
| | - Dalla Doohan
- Institute of Tropical Disease, Universitas Airlangga, Surabaya 60115, Indonesia; (D.D.); (L.A.W.); (K.A.F.); (Y.A.A.R.)
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
| | - Ari Fahrial Syam
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Indonesia, Jakarta 10430, Indonesia; (A.F.S.); (H.M.)
| | - Iswan Abbas Nusi
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya 60286, Indonesia; (I.A.N.); (T.S.); (A.C.)
| | - Phawinee Subsomwong
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Indonesia, Jakarta 10430, Indonesia; (A.F.S.); (H.M.)
| | - Langgeng Agung Waskito
- Institute of Tropical Disease, Universitas Airlangga, Surabaya 60115, Indonesia; (D.D.); (L.A.W.); (K.A.F.); (Y.A.A.R.)
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
| | - Hasan Maulahela
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Fardah Akil
- Center of Gastroentero-Hepatology, Department of Internal Medicine, Faculty of Medicine, Hasanuddin University, Makassar 90245, Indonesia;
| | - Willy Brodus Uwan
- Department of Internal Medicine, Santo Antonius Hospital, Pontianak 78243, Indonesia;
| | - Gontar Siregar
- Division of Gastroentero-Hepatology, Department of Internal Medicine, Faculty of Medicine, University of Sumatra Utara, Medan 20155, Indonesia;
| | - Kartika Afrida Fauzia
- Institute of Tropical Disease, Universitas Airlangga, Surabaya 60115, Indonesia; (D.D.); (L.A.W.); (K.A.F.); (Y.A.A.R.)
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
| | - Yudith Annisa Ayu Rezkitha
- Institute of Tropical Disease, Universitas Airlangga, Surabaya 60115, Indonesia; (D.D.); (L.A.W.); (K.A.F.); (Y.A.A.R.)
- Faculty of Medicine, University of Muhammadiyah Surabaya, Surabaya 60113, Indonesia
| | - Abdul Rahman
- Department of Internal Medicine, Kolaka General Hospital, Kolaka 93511, Indonesia;
| | - I Dewa Nyoman Wibawa
- Division of Gastroentero-Hepatology, Department of Internal Medicine, Faculty of Medicine, University of Udayana, Denpasar 80232, Indonesia;
| | | | - Marselino Richardo
- Department of Internal Medicine, Merauke City General Hospital, Merauke 99613, Indonesia;
| | - Titong Sugihartono
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya 60286, Indonesia; (I.A.N.); (T.S.); (A.C.)
| | - Alvi Chomariyati
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya 60286, Indonesia; (I.A.N.); (T.S.); (A.C.)
| | - Taufan Bramantoro
- Department of Dental Public Health, Faculty of Dental Medicine, Universitas Airlangga, Surabaya 60131, Indonesia;
| | - Tomohisa Uchida
- Department of Molecular Pathology, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
| | - Yoshio Yamaoka
- Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya 60286, Indonesia; (I.A.N.); (T.S.); (A.C.)
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan;
- Global Oita Medical Advanced Research Center for Health, Oita University, Yufu 879-5593, Japan
- Department of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, TX 77030, USA
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Lin YA, Wang H, Gu ZJ, Wang WJ, Zeng XY, Du YL, Ying SS, Zhang BH. Effect of CYP2C19 Gene Polymorphisms on Proton Pump Inhibitor, Amoxicillin, and Levofloxacin Triple Therapy for Eradication of Helicobacter Pylori. Med Sci Monit 2017; 23:2701-2707. [PMID: 28577017 PMCID: PMC5467706 DOI: 10.12659/msm.901514] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The effects of PPI are variable owing to the CYP2C19 polymorphisms. However, whether the polymorphisms could affect the Hp eradication efficacy of triple therapy is still not clear. The present study aimed to assess the effects of CYP2C19 gene polymorphisms on proton pump inhibitor (PPI), amoxicillin, and levofloxacin triple therapy for Helicobacter pylori (Hp) eradication. MATERIAL AND METHODS We randomly assigned 160 Hp-positive patients with chronic gastritis to 2 groups to receive either 20 mg bid omeprazole (OAL group, n=80) or 10 mg bid rabeprazole (RAL group, n=80), combined with 1000 mg bid amoxicillin and 500 mg qd levofloxacin. The 2 groups were treated for 10 days. The CYP2C19 genotypes included wild-type, M1 mutant gene (*2, the mutation of exon 5), and M2 mutant gene (*3, the mutation of exon 4) identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFIP). According to CYP2C19 genotype combinations, the patients were divided into extensive metabolizer (EM), intermediate metabolizer (IM), and poor metabolizer (PM) subgroups. The eradication efficacy of Hp was evaluated by 14C-UBT at 28 days after treatment. RESULTS The trial was completed by 155 patients. Hp eradication rates in OAL and RAL groups were 78.2% and 88.3%, respectively, on per-protocol (PP) analysis, indicating no significant difference (P>0.05). Regarding CYP2C19 genotypes, eradication rates of 60.7%, 84.2%, and 100% were obtained for EM, IM, and PM subgroups, respectively, of the OAL group. EM group eradication rates were significantly lower than IM and PM group values (P<0.05). In the RAL group, no such difference was observed (P>0.05). Hp eradication rates were significantly lower in the EM subgroup of the OAL group compared with that of the RAL group. CONCLUSIONS Hp eradication rates were higher in the RAL group than in OAL-treated patients. Interestingly, omeprazole-based therapy was significantly affected by the CYP2C19 genotype, unlike the rabeprazole-based therapy.
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Affiliation(s)
- Yun-An Lin
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Hong Wang
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Zhu-Jun Gu
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Wen-Jia Wang
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Xiao-Yan Zeng
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Yan-Lei Du
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Song-Song Ying
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
| | - Bo-Hua Zhang
- Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou, Guangdong, China (mainland)
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Uehara S, Kawano M, Murayama N, Uno Y, Utoh M, Inoue T, Sasaki E, Yamazaki H. Oxidation of R- and S-omeprazole stereoselectively mediated by liver microsomal cytochrome P450 2C19 enzymes from cynomolgus monkeys and common marmosets. Biochem Pharmacol 2016; 120:56-62. [DOI: 10.1016/j.bcp.2016.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/14/2016] [Indexed: 10/21/2022]
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Gao N, Tian X, Fang Y, Zhou J, Zhang H, Wen Q, Jia L, Gao J, Sun B, Wei J, Zhang Y, Cui M, Qiao H. Gene polymorphisms and contents of cytochrome P450s have only limited effects on metabolic activities in human liver microsomes. Eur J Pharm Sci 2016; 92:86-97. [PMID: 27339126 DOI: 10.1016/j.ejps.2016.06.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/16/2016] [Accepted: 06/18/2016] [Indexed: 12/22/2022]
Abstract
Extensive inter-individual variations in pharmacokinetics are considered as a major reason for unpredictable drug responses. As the most important drug metabolic enzymes, inter-individual variations of cytochrome P450 (CYP) activities are not clear in human liver. In this paper, metabolic activities, gene polymorphisms and protein contents of 10 CYPs were determined in 105 human normal liver microsomes. The results indicated substantial inter-individual variations in CYP activities, with the greatest being CYP2C19 activity (>600-fold). Only half of 10 CYP isoforms and 26 gene polymorphism sites had limited effects on metabolic activities, such as CYP2A6, CYP2B6, CYP2C9, CYP2D6 and CYP3A4/5, others had almost no effects. Compared with their respective wild type, Km, Vmax, and CLint decreased by 51.6%, 88.7% and 70.7% in CYP2A6*1/*4 genotype, Vmax and CLint decreased by 32.8% and 60.2% in CYP2C9*1/*3 genotype, Km increased by 118.4% and CLint decreased by 65.2% in CYP2D6 100TT genotype, respectively. Moreover, there were only 4 CYP isoforms, CYP1A2, CYP2A6, CYP2E1 and CYP3A5, which had moderate or weak correlations between Vmax values and corresponding contents. In conclusions, the genotypes and contents of some CYPs have only limited effects on metabolic activities, which imply that there are other more important factors to influence inter-individual variations.
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Affiliation(s)
- Na Gao
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Xin Tian
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Yan Fang
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Jun Zhou
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Haifeng Zhang
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Qiang Wen
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Linjing Jia
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Jie Gao
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Bao Sun
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Jingyao Wei
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Yunfei Zhang
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Mingzhu Cui
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China
| | - Hailing Qiao
- Institute of Clinical Pharmacology, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan Province 450052, People's Republic of China.
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Xie Q, Chen Y, Liu F, Zhong Z, Zhao K, Ling Z, Wang F, Tang X, Wang Z, Liu L, Liu X. Interspecies differences in metabolism of deoxypodophyllotoxin in hepatic microsomes from human, monkey, rat, mouse and dog. Drug Metab Pharmacokinet 2016; 31:314-22. [PMID: 27329261 DOI: 10.1016/j.dmpk.2016.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 01/11/2023]
Abstract
Deoxypodophyllotoxin (DPT) is a natural lignan product which has drawn much attention due to its pharmacological properties including antitumor effect. The purpose of this study was to investigate interspecies differences in metabolism of DPT in hepatic microsomes from human (HLM), cynomolgus monkey (CyLM), rat (RLM), mouse (MLM) and dog (DLM). Incubation of DPT with hepatic microsomes from five species in the presence of NADPH resulted in formation of seven metabolites, five of which were compared with the synthetic standards. M2 was the most abundant metabolite in microsomes from all species. Rank order of intrinsic clearance for M2 formation was RLM > CyLM > MLM > HLM > DLM. In HLM, sulfaphenazole showed the strongest inhibition effect on M2 formation, but neither ticlopidine nor ketoconazole inhibited M2 formation in HLM. Results from cDNA-expressed human CYP450s experiments showed that clearance of M2 formation was much higher in CYP2C9 and CYP2C19 than that in CYP3A4. Contributions of the three CYP450 isoforms to M2 formation in HLM were estimated using relative activity factor (RAF) method or correction by amount of CYP450 isoforms in HLM. M2 formation in HLM was mainly attributed to CYP2C9, followed by CYP2C19. Involvement of CYP3A4 was minor.
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Affiliation(s)
- Qiushi Xie
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Yang Chen
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Fei Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Zeyu Zhong
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Kaijing Zhao
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Zhaoli Ling
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Fan Wang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Xiange Tang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Zhongjian Wang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Li Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
| | - Xiaodong Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
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Shah RR, Smith RL. Addressing phenoconversion: the Achilles' heel of personalized medicine. Br J Clin Pharmacol 2015; 79:222-40. [PMID: 24913012 PMCID: PMC4309629 DOI: 10.1111/bcp.12441] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/04/2014] [Indexed: 02/06/2023] Open
Abstract
Phenoconversion is a phenomenon that converts genotypic extensive metabolizers (EMs) into phenotypic poor metabolizers (PMs) of drugs, thereby modifying their clinical response to that of genotypic PMs. Phenoconversion, usually resulting from nongenetic extrinsic factors, has a significant impact on the analysis and interpretation of genotype-focused clinical outcome association studies and personalizing therapy in routine clinical practice. The high phenotypic variability or genotype-phenotype mismatch, frequently observed due to phenoconversion within the genotypic EM population, means that the real number of phenotypic PM subjects may be greater than predicted from their genotype alone, because many genotypic EMs would be phenotypically PMs. If the phenoconverted population with genotype-phenotype mismatch, most extensively studied for CYP2D6, is as large as the evidence suggests, there is a real risk that genotype-focused association studies, typically correlating only the genotype with clinical outcomes, may miss clinically strong pharmacogenetic associations, thus compromising any potential for advancing the prospects of personalized medicine. This review focuses primarily on co-medication-induced phenoconversion and discusses potential approaches to rectify some of the current shortcomings. It advocates routine phenotyping of subjects in genotype-focused association studies and proposes a new nomenclature to categorize study populations. Even with strong and reliable data associating patients' genotypes with clinical outcome(s), there are problems clinically in applying this knowledge into routine pharmacotherapy because of potential genotype-phenotype mismatch. Drug-induced phenoconversion during routine clinical practice remains a major public health issue. Therefore, the principal challenges facing personalized medicine, which need to be addressed, include identification of the following factors: (i) drugs that are susceptible to phenoconversion; (ii) co-medications that can cause phenoconversion; and (iii) dosage amendments that need to be applied during and following phenoconversion.
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Affiliation(s)
| | - Robert L Smith
- Department of Surgery and Cancer, Faculty of Medicine, Imperial CollegeLondon, UK
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Jia LL, Zhong ZY, Li F, Ling ZL, Chen Y, Zhao WM, Li Y, Jiang SW, Xu P, Yang Y, Hu MY, Liu L, Liu XD. The Aggravation of Clozapine-Induced Hepatotoxicity by Glycyrrhetinic Acid in Rats. J Pharmacol Sci 2014; 124:468-79. [DOI: 10.1254/jphs.13257fp] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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