1
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Turner AJ, Nofziger C, Ramey BE, Ly RC, Bousman CA, Agúndez JAG, Sangkuhl K, Whirl-Carrillo M, Vanoni S, Dunnenberger HM, Ruano G, Kennedy MA, Phillips MS, Hachad H, Klein TE, Moyer AM, Gaedigk A. PharmVar Tutorial on CYP2D6 Structural Variation Testing and Recommendations on Reporting. Clin Pharmacol Ther 2023; 114:1220-1237. [PMID: 37669183 PMCID: PMC10840842 DOI: 10.1002/cpt.3044] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/23/2023] [Indexed: 09/07/2023]
Abstract
The Pharmacogene Variation Consortium (PharmVar) provides nomenclature for the highly polymorphic human CYP2D6 gene locus and a comprehensive summary of structural variation. CYP2D6 contributes to the metabolism of numerous drugs and, thus, genetic variation in its gene impacts drug efficacy and safety. To accurately predict a patient's CYP2D6 phenotype, testing must include structural variants including gene deletions, duplications, hybrid genes, and combinations thereof. This tutorial offers a comprehensive overview of CYP2D6 structural variation, terms, and definitions, a review of methods suitable for their detection and characterization, and practical examples to address the lack of standards to describe CYP2D6 structural variants or any other pharmacogene. This PharmVar tutorial offers practical guidance on how to detect the many, often complex, structural variants, as well as recommends terms and definitions for clinical and research reporting. Uniform reporting is not only essential for electronic health record-keeping but also for accurate translation of a patient's genotype into phenotype which is typically utilized to guide drug therapy.
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Affiliation(s)
- Amy J Turner
- Department of Pediatrics, Children’s Research Institute, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- RPRD Diagnostics LLC, Wauwatosa, Wisconsin, USA
| | | | | | - Reynold C Ly
- Department of Medical and Molecular Genetics, Division of Diagnostic Genomics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Chad A Bousman
- Department of Medical Genetics, University of Calgary, Calgary, Alberta, Canada
| | - José AG Agúndez
- University of Extremadura, Cáceres, Spain
- Institute of Molecular Pathology Biomarkers, Cáceres, Spain
| | - Katrin Sangkuhl
- Department of Biomedical Data Science, Stanford University, Stanford, California, USA
| | | | | | - Henry M Dunnenberger
- Mark R. Neaman Center for Personalized Medicine, NorthShore University Health System, Evanston, Illinois, USA
| | - Gualberto Ruano
- Institute of Living, Hartford Hospital (Hartford CT) and Department of Psychiatry, University of Connecticut School of Medicine (Farmington CT), USA
| | - Martin A Kennedy
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | | | - Houda Hachad
- Houda Hachad, Department of Clinical Operations, AccessDx Laboratories, Houston, Texas, USA
| | - Teri E Klein
- Departments of Biomedical Data Science and Medicine (BMIR), Stanford University, Stanford, California, USA
| | - Ann M Moyer
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrea Gaedigk
- Children’s Mercy Research Institute (CMRI), Kansas City, Missouri, USA
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
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2
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Beaulieu AM, Tabasky E, Osser DN. The psychopharmacology algorithm project at the Harvard South Shore Program: An algorithm for adults with obsessive-compulsive disorder. Psychiatry Res 2019; 281:112583. [PMID: 31600606 DOI: 10.1016/j.psychres.2019.112583] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/26/2019] [Accepted: 09/26/2019] [Indexed: 12/28/2022]
Abstract
A previous algorithm for the pharmacological treatment of obsessive-compulsive disorder was published in 2012. Developments over the past 7 years suggest an update is needed. The authors conducted searches in PubMed, focusing on new studies and reviews since 2012 that would support or change previous recommendations. We identified exceptions to the main algorithm, including pregnant women and women of child-bearing potential, the elderly, and patients with common medical and psychiatric co-morbidities. Selective serotonin reuptake inhibitors (SSRIs) are still first-line. An adequate trial requires a period at typical antidepressant doses and dose adjustments guided by a plasma level to evaluate for poor adherence or ultra-rapid metabolism. If the response is inadequate, consider a trial of another SSRI this time possibly taken to a very high dose. Clomipramine could be an alternative. If the response to the second trial remains inadequate, the next recommendation is to augment with aripiprazole or risperidone. Alternatively, augmentation with novel agents could be selected, including glutamatergic (memantine, riluzole, topiramate, n-acetylcysteine, lamotrigine), serotonergic (ondansetron), and anti-inflammatory (minocycline, celecoxib) agents. A third option could be transcranial magnetic stimulation. Lastly, after several of these trials, deep brain stimulation and cingulotomy have evidence for a role in the most treatment-refractory patients.
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Affiliation(s)
- Ashley M Beaulieu
- Department of Psychiatry, Harvard Medical School, VA Boston Healthcare System, Brockton Division, 940 Belmont Street, Brockton, MA 02301, United States
| | - Edward Tabasky
- Department of Psychiatry, NYS Psychiatric Institute, Columbia University College of Physicians and Surgeons, 1051 Riverside Drive, Box 111, New York, NY 10032, United States
| | - David N Osser
- Department of Psychiatry, Harvard Medical School, VA Boston Healthcare System, Brockton Division, 940 Belmont Street, Brockton, MA 02301, United States.
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3
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Marazziti D, Avella MT, Basile L, Mucci F, Dell'Osso L. Pharmacokinetics of serotonergic drugs: focus on OCD. Expert Opin Drug Metab Toxicol 2019; 15:261-273. [PMID: 30793987 DOI: 10.1080/17425255.2019.1584611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Although the treatment of obsessive-compulsive disorder (OCD), a common, chronic, and disabling psychiatric condition, has significantly improved in the last decades, with the demonstration of the specific effectiveness of serotonin reuptake inhibitors (SRIs), a large proportion of patients still show high relapse rates. In addition, pharmacological treatments should be maintained for years, so that the clinicians should take into account the pharmacokinetic changes in the long-term, which may be responsible for dangerous side effects or interactions. Areas covered: The aim of this paper was to review the literature on the pharmacokinetics of SSRIs and clomipramine, and on their pharmacokinetic parameters in OCD patients. Expert opinion: Although the literature on the pharmacokinetics of both clomipramine and SSRIs is consistent, data on pharmacokinetic parameters in OCD patients are very few. Given the impact of OCD, its chronicity requiring long-term treatments, together with the need to increase the clinical response rate, more studies in this field are urgently required.
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Affiliation(s)
- Donatella Marazziti
- a Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry , University of Pisa , Pisa , Italy
| | - Maria Teresa Avella
- a Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry , University of Pisa , Pisa , Italy
| | - Lucia Basile
- a Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry , University of Pisa , Pisa , Italy
| | - Federico Mucci
- a Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry , University of Pisa , Pisa , Italy
| | - Liliana Dell'Osso
- a Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry , University of Pisa , Pisa , Italy
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4
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Lam YWF. Principles of Pharmacogenomics. Pharmacogenomics 2019. [DOI: 10.1016/b978-0-12-812626-4.00001-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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5
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Pharmacogenomics in Psychiatric Disorders. Pharmacogenomics 2019. [DOI: 10.1016/b978-0-12-812626-4.00007-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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6
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Rahikainen AL, Vauhkonen P, Pett H, Palo JU, Haukka J, Ojanperä I, Niemi M, Sajantila A. Completed suicides of citalopram users-the role of CYP genotypes and adverse drug interactions. Int J Legal Med 2018; 133:353-363. [PMID: 30173302 DOI: 10.1007/s00414-018-1927-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/24/2018] [Indexed: 12/25/2022]
Abstract
Depression is known to be a risk factor for suicide. Currently, the most used antidepressants are selective serotonin reuptake inhibitors (SSRIs). Not all users, however, benefit from them. In such cases, treatment failure can be explained in part by genetic differences. In this study, we investigated the role of pharmacogenetic factors in citalopram-positive completed suicides (n = 349). Since citalopram is metabolized by CYP2C19 and CYP2D6 enzymes, the study population was genotyped for clinically relevant CYP2C19 and CYP2D6 polymorphisms and CYP2D6 copy number variation. To assess genetic differences between suicide cases and Finns in general, Finnish population samples (n = 855) were used as controls. Also, the role of drug interactions among suicide cases was evaluated. We found enrichment of a combined group of genetically predicted poor and ultrarapid metabolizer phenotypes (gMPs) of CYP2C19 among suicide victims compared to controls 0.356 [0.31-0.41] vs. 0.265 [0.24-0.30] (p = 0.0065). In CYP2D6 gMPs, there was no difference between cases and controls when the study population was analyzed as a whole. However, there were significantly more poor metabolizers among females who committed suicide by poisoning compared to female controls. In 8% of all drug poisoning deaths, lifetime drug-drug interaction was evaluated having a contribution to the fatal outcome. From clinical perspective, pharmacogenetic testing prior to initiation of SSRI drug could be beneficial. It may also be useful in medico-legal settings as it may elucidate obscure poisoning cases. Also, the possibility of unintentional drug interactions should be taken into account in drug poisoning deaths.
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Affiliation(s)
- Anna-Liina Rahikainen
- Department of Forensic Medicine, University of Helsinki, P.O.Box 40, Kytösuontie 11, 00014, Helsinki, Finland.
| | - P Vauhkonen
- Forensic Medicine Unit, National Institute for Health and Welfare, P.O.Box 30, Mannerheimintie 166, 00271, Helsinki, Finland
| | - H Pett
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Clinical Pharmacology, University of Helsinki and Helsinki University Central Hospital, P.O.Box 20, Tukholmankatu 8C, 00014, Helsinki, Finland
| | - J U Palo
- Department of Forensic Medicine, University of Helsinki, P.O.Box 40, Kytösuontie 11, 00014, Helsinki, Finland.,Forensic Genetics Unit, National Institute for Health and Welfare, P.O.Box 30, Mannerheimintie 166, 00271, Helsinki, Finland
| | - J Haukka
- Department of Public Health, University of Helsinki, P.O.Box 20, Tukholmankatu 8B, 00014, Helsinki, Finland
| | - I Ojanperä
- Department of Forensic Medicine, University of Helsinki, P.O.Box 40, Kytösuontie 11, 00014, Helsinki, Finland.,Forensic Toxicology Unit, National Institute for Health and Welfare, P.O.Box 30, Mannerheimintie 166, 00271, Helsinki, Finland
| | - M Niemi
- Department of Clinical Pharmacology, University of Helsinki and Helsinki University Central Hospital, P.O.Box 20, Tukholmankatu 8C, 00014, Helsinki, Finland
| | - Antti Sajantila
- Department of Forensic Medicine, University of Helsinki, P.O.Box 40, Kytösuontie 11, 00014, Helsinki, Finland.
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7
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CYP 2D6* 4 polymorphism in Polycythemia vera patients in Turkish population. MARMARA MEDICAL JOURNAL 2018. [DOI: 10.5472/marumj.430790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Santini SA, Panza F, Lozupone M, Bellomo A, Greco A, Seripa D. Genetics of tailored medicine: Focus on CNS drugs. Microchem J 2018. [DOI: 10.1016/j.microc.2017.02.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Seripa D, Lozupone M, Stella E, Paroni G, Bisceglia P, La Montagna M, D’onofrio G, Gravina C, Urbano M, Priore MG, Lamanna A, Daniele A, Bellomo A, Logroscino G, Greco A, Panza F. Psychotropic drugs and CYP2D6 in late-life psychiatric and neurological disorders. What do we know? Expert Opin Drug Saf 2017; 16:1373-1385. [DOI: 10.1080/14740338.2017.1389891] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Davide Seripa
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Madia Lozupone
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Eleonora Stella
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Giulia Paroni
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Paola Bisceglia
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Maddalena La Montagna
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Grazia D’onofrio
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Carolina Gravina
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Maria Urbano
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Maria Giovanna Priore
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Angela Lamanna
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Antonio Daniele
- Institute of Neurology, Catholic University of Sacred Heart, Rome, Italy
| | - Antonello Bellomo
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Giancarlo Logroscino
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
- Department of Clinical Research in Neurology, University of Bari Aldo Moro, “Pia Fondazione Cardinale G. Panico”, Tricase, Lecce, Italy
| | - Antonio Greco
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
| | - Francesco Panza
- Complex Structure of Geriatrics, Department of Medical Sciences, IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
- Department of Clinical Research in Neurology, University of Bari Aldo Moro, “Pia Fondazione Cardinale G. Panico”, Tricase, Lecce, Italy
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10
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Abstract
PURPOSE/BACKGROUND This commentary deals with the neglected issue of the art of psychopharmacology by recounting the authors' journeys. METHODS/PROCEDURES First, a model of medical science situated within the history of medicine is described including (1) a limitation of the mathematical model of science, (2) the distinction between mechanistic science and mathematical science, (3) how this distinction is applied to medicine, and (4) how this distinction is applied to explain pharmacology to psychiatrists. Second, the neglected art of psychopharmacology is addressed by explaining (1) where the art of psychopharmacotherapy was hiding in the first author's psychopharmacology research, (2) how the Health Belief Model was applied to the art of medicine, (3) how the second author became interested in the Health Belief Model, and (4) his studies introducing the Health Belief Model in psychopharmacology. The authors' collaboration led to: (1) study of the effect of pharmacophobia on poor adherence and (2) reflection on the limits of the art of psychopharmacology. FINDINGS/RESULTS Low adherence was found in 45% (116/258) of psychiatric patients with pharmacophobia versus 22% (149/682) in those with no pharmacophobia, providing an odds ratio of 2.9 (95% confidence interval, 2.2-4.0) and an adjusted odds ratio of 2.5 (95% confidence interval, 1.8-3.5) after adjusting for other variables contributing to poor adherence. IMPLICATIONS/CONCLUSIONS Different cognitive patterns in different patients may contribute to poor adherence. Specific interventions targeting these varying cognitive styles may be needed in different patients to improve drug adherence.
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11
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Hicks JK, Sangkuhl K, Swen JJ, Ellingrod VL, Müller DJ, Shimoda K, Bishop JR, Kharasch ED, Skaar TC, Gaedigk A, Dunnenberger HM, Klein TE, Caudle KE, Stingl JC. Clinical pharmacogenetics implementation consortium guideline (CPIC) for CYP2D6 and CYP2C19 genotypes and dosing of tricyclic antidepressants: 2016 update. Clin Pharmacol Ther 2017; 102:37-44. [PMID: 27997040 DOI: 10.1002/cpt.597] [Citation(s) in RCA: 381] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/21/2016] [Accepted: 12/07/2016] [Indexed: 11/06/2022]
Affiliation(s)
- J K Hicks
- DeBartolo Family Personalized Medicine Institute, Division of Population Science, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
| | - K Sangkuhl
- Department of Genetics, Stanford University, Stanford, California, USA
| | - J J Swen
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - V L Ellingrod
- Department of Clinical, Social and Administrative Sciences, College of Pharmacy, and Department of Psychiatry, School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - D J Müller
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - K Shimoda
- Department of Psychiatry, Dokkyo Medical University, Japan
| | - J R Bishop
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, and Department of Psychiatry, College of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - E D Kharasch
- Division of Clinical and Translational Research, Department of Anesthesiology, Washington University in St, Louis, St, Louis, Missouri, USA
| | - T C Skaar
- Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - A Gaedigk
- Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children's Mercy, Kansas City, Missouri and Department of Pediatrics, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - H M Dunnenberger
- Center for Molecular Medicine, NorthShore University HealthSystem, Evanston, Illinois, USA
| | - T E Klein
- Department of Genetics, Stanford University, Stanford, California, USA
| | - K E Caudle
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - J C Stingl
- Division of Research, Federal Institute of Drugs and Medical Devices, Bonn, Germany
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12
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Lozupone M, Panza F, Stella E, La Montagna M, Bisceglia P, Miscio G, Galizia I, Daniele A, di Mauro L, Bellomo A, Logroscino G, Greco A, Seripa D. Pharmacogenetics of neurological and psychiatric diseases at older age: has the time come? Expert Opin Drug Metab Toxicol 2016; 13:259-277. [DOI: 10.1080/17425255.2017.1246533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Madia Lozupone
- Unit of Neurodegenerative Disease, Department of Basic Medicine Sciences, Neuroscience, and Sense Organs, University of Bari ‘Aldo Moro,’, Bari, Italy
| | - Francesco Panza
- Unit of Neurodegenerative Disease, Department of Basic Medicine Sciences, Neuroscience, and Sense Organs, University of Bari ‘Aldo Moro,’, Bari, Italy
- Unit of Neurodegenerative Disease, Department of Clinical Research in Neurology, University of Bari ‘Aldo Moro’ at ‘Pia Fondazione Card. G. Panico,’, Tricase, Lecce, Italy
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Eleonora Stella
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Maddalena La Montagna
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Paola Bisceglia
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Giuseppe Miscio
- Laboratory of Clinical Chemistry, Department of Clinical Pathology, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Ilaria Galizia
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Antonio Daniele
- Institute of Neurology, Catholic University of Sacred Heart, Rome, Italy
| | - Lazzaro di Mauro
- Laboratory of Clinical Chemistry, Department of Clinical Pathology, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Antonello Bellomo
- Psychiatric Unit, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Giancarlo Logroscino
- Unit of Neurodegenerative Disease, Department of Basic Medicine Sciences, Neuroscience, and Sense Organs, University of Bari ‘Aldo Moro,’, Bari, Italy
- Unit of Neurodegenerative Disease, Department of Clinical Research in Neurology, University of Bari ‘Aldo Moro’ at ‘Pia Fondazione Card. G. Panico,’, Tricase, Lecce, Italy
| | - Antonio Greco
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Davide Seripa
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
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13
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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: 172] [Impact Index Per Article: 19.1] [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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14
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Human gene copy number variation and infectious disease. Hum Genet 2014; 133:1217-33. [PMID: 25110110 DOI: 10.1007/s00439-014-1457-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/20/2014] [Indexed: 01/05/2023]
Abstract
Variability in the susceptibility to infectious disease and its clinical manifestation can be determined by variation in the environment and by genetic variation in the pathogen and the host. Despite several successes based on candidate gene studies, defining the host variation affecting infectious disease has not been as successful as for other multifactorial diseases. Both single nucleotide variation and copy number variation (CNV) of the host contribute to the host's susceptibility to infectious disease. In this review we focus on CNV, particularly on complex multiallelic CNV that is often not well characterised either directly by hybridisation methods or indirectly by analysis of genotypes and flanking single nucleotide variants. We summarise the well-known examples, such as α-globin deletion and susceptibility to severe malaria, as well as more recent controversies, such as the extensive CNV of the chemokine gene CCL3L1 and HIV infection. We discuss the potential biological mechanisms that could underly any genetic association and reflect on the extensive complexity and functional variation generated by a combination of CNV and sequence variation, as illustrated by the Fc gamma receptor genes FCGR3A, FCGR3B and FCGR2C. We also highlight some understudied areas that might prove fruitful areas for further research.
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15
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Crowley JJ, Kim Y, Lenarcic AB, Quackenbush CR, Barrick CJ, Adkins DE, Shaw GS, Miller DR, de Villena FPM, Sullivan PF, Valdar W. Genetics of adverse reactions to haloperidol in a mouse diallel: a drug-placebo experiment and Bayesian causal analysis. Genetics 2014; 196:321-47. [PMID: 24240528 PMCID: PMC3872195 DOI: 10.1534/genetics.113.156901] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/14/2013] [Indexed: 12/21/2022] Open
Abstract
Haloperidol is an efficacious antipsychotic drug that has serious, unpredictable motor side effects that limit its utility and cause noncompliance in many patients. Using a drug-placebo diallel of the eight founder strains of the Collaborative Cross and their F1 hybrids, we characterized aggregate effects of genetics, sex, parent of origin, and their combinations on haloperidol response. Treating matched pairs of both sexes with drug or placebo, we measured changes in the following: open field activity, inclined screen rigidity, orofacial movements, prepulse inhibition of the acoustic startle response, plasma and brain drug level measurements, and body weight. To understand the genetic architecture of haloperidol response we introduce new statistical methodology linking heritable variation with causal effect of drug treatment. Our new estimators, "difference of models" and "multiple-impute matched pairs", are motivated by the Neyman-Rubin potential outcomes framework and extend our existing Bayesian hierarchical model for the diallel (Lenarcic et al. 2012). Drug-induced rigidity after chronic treatment was affected by mainly additive genetics and parent-of-origin effects (accounting for 28% and 14.8% of the variance), with NZO/HILtJ and 129S1/SvlmJ contributions tending to increase this side effect. Locomotor activity after acute treatment, by contrast, was more affected by strain-specific inbreeding (12.8%). In addition to drug response phenotypes, we examined diallel effects on behavior before treatment and found not only effects of additive genetics (10.2-53.2%) but also strong effects of epistasis (10.64-25.2%). In particular: prepulse inhibition showed additivity and epistasis in about equal proportions (26.1% and 23.7%); there was evidence of nonreciprocal epistasis in pretreatment activity and rigidity; and we estimated a range of effects on body weight that replicate those found in our previous work. Our results provide the first quantitative description of the genetic architecture of haloperidol response in mice and indicate that additive, dominance-like inbreeding and parent-of-origin effects contribute strongly to treatment effect heterogeneity for this drug.
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Affiliation(s)
- James J. Crowley
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Yunjung Kim
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Alan B. Lenarcic
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Corey R. Quackenbush
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Cordelia J. Barrick
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Daniel E. Adkins
- Center for Biomarker Research and Personalized Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Ginger S. Shaw
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - Darla R. Miller
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | | | - Patrick F. Sullivan
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
| | - William Valdar
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-7264
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Meier F, Kontekakis A, Schöffski O. Bewertung der Einsparpotenziale in der Arzneimitteltherapie durch Dosisanpassung an die Polymorphismen im Cytochrom P450. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/bf03320779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Cytochrome P450 enzymes in drug metabolism: regulation of gene expression, enzyme activities, and impact of genetic variation. Pharmacol Ther 2013; 138:103-41. [PMID: 23333322 DOI: 10.1016/j.pharmthera.2012.12.007] [Citation(s) in RCA: 2460] [Impact Index Per Article: 223.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 12/27/2012] [Indexed: 02/06/2023]
Abstract
Cytochromes P450 (CYP) are a major source of variability in drug pharmacokinetics and response. Of 57 putatively functional human CYPs only about a dozen enzymes, belonging to the CYP1, 2, and 3 families, are responsible for the biotransformation of most foreign substances including 70-80% of all drugs in clinical use. The highest expressed forms in liver are CYPs 3A4, 2C9, 2C8, 2E1, and 1A2, while 2A6, 2D6, 2B6, 2C19 and 3A5 are less abundant and CYPs 2J2, 1A1, and 1B1 are mainly expressed extrahepatically. Expression of each CYP is influenced by a unique combination of mechanisms and factors including genetic polymorphisms, induction by xenobiotics, regulation by cytokines, hormones and during disease states, as well as sex, age, and others. Multiallelic genetic polymorphisms, which strongly depend on ethnicity, play a major role for the function of CYPs 2D6, 2C19, 2C9, 2B6, 3A5 and 2A6, and lead to distinct pharmacogenetic phenotypes termed as poor, intermediate, extensive, and ultrarapid metabolizers. For these CYPs, the evidence for clinical significance regarding adverse drug reactions (ADRs), drug efficacy and dose requirement is rapidly growing. Polymorphisms in CYPs 1A1, 1A2, 2C8, 2E1, 2J2, and 3A4 are generally less predictive, but new data on CYP3A4 show that predictive variants exist and that additional variants in regulatory genes or in NADPH:cytochrome P450 oxidoreductase (POR) can have an influence. Here we review the recent progress on drug metabolism activity profiles, interindividual variability and regulation of expression, and the functional and clinical impact of genetic variation in drug metabolizing P450s.
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18
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Lam YF, Fukui N, Sugai T, Watanabe J, Watanabe Y, Suzuki Y, Someya T. Pharmacogenomics in Psychiatric Disorders. Pharmacogenomics 2013. [DOI: 10.1016/b978-0-12-391918-2.00006-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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19
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Andresen H, Augustin C, Streichert T. Toxicogenetics--cytochrome P450 microarray analysis in forensic cases focusing on morphine/codeine and diazepam. Int J Legal Med 2012; 127:395-404. [PMID: 22899355 DOI: 10.1007/s00414-012-0759-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 08/03/2012] [Indexed: 01/10/2023]
Abstract
Genetic polymorphisms in cytochrome P 450 (CYP) enzymes could lead to a phenotype with altered enzyme activity. In pharmacotherapy, genotype-based dose recommendations achieved great importance for several drugs. In our pilot study, we ask if these genetic tests should be applied to forensic problems as a matter of routine. Starting from 2004 through 2008, we screened routine cases for samples where the relation of parent compound to metabolite(s) (P/M ratio), particularly morphine to codeine ratios and diazepam to its metabolites, was noticeable or not consistent with the information provided by the defendants. We found 11 samples with conspicuous results. These were analyzed for polymorphisms of the CYP 2D6 and 2C19 genes using the Roche AmpliChip Cytochrome P450 Genotyping test. If not previously conducted, a general unknown analysis by gas chromatography/mass spectrometry (GC/MS) was additionally carried out. For CYP 2D6, we found two cases with the genotype poor metabolizer (PM), three cases with heterozygote extensive metabolizer genotype classified as an intermediate metabolizer (IM) with probably reduced enzyme activities, but no ultrarapid metabolizer genotype. For CYP 2C19, two cases were characterized as IM phenotypes, with no PM found. Once we achieved no appropriate amounts of DNA, one case was excluded after GC/MS analysis. Only in one case could the polymorphism clearly explain the changes in drug metabolism. More frequently, a drug-drug interaction was thought to have a stronger impact. Additionally, our results suggest that IM genotypes may be more relevant than previously suspected. With respect to the small number of cases in which we thought a genotyping would be helpful, we conclude that the overall relevance of toxicogenetics in forensic problems is moderate. However, in some individual cases, a genotyping may provide new insight.
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Affiliation(s)
- H Andresen
- Institute of Legal Medicine, Forensic Toxicology, University Medical Center Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany.
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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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Teh LK, Mohamed NI, Salleh MZ, Rohaizak M, Shahrun NS, Saladina JJ, Shia JKS, Roslan H, Sood S, Rajoo TS, Muniandy SP, Henry G, Ngow HA, Hla U KT, Din J. The risk of recurrence in breast cancer patients treated with tamoxifen: polymorphisms of CYP2D6 and ABCB1. AAPS JOURNAL 2011; 14:52-9. [PMID: 22183189 DOI: 10.1208/s12248-011-9313-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Accepted: 11/28/2011] [Indexed: 01/26/2023]
Abstract
CYP2D6 plays a major role in the metabolism of tamoxifen, and polymorphism of P-glycoprotein has been associated with resistance of many drug therapies. This study investigates the clinical impact of genetic variants of CYP2D6 and ABCB1 in breast cancer patients treated with tamoxifen. Blood samples from 95 breast cancer patients treated with tamoxifen were collected and genotyped for CYP2D6 and ABCB1 variants using allele-specific PCR method. Recurrence risks were calculated using Kaplan-Meier analysis and compared using the log-rank test. Patients carrying CYP2D6*10/*10 and heterozygous null allele (IM) showed higher risks of developing recurrence and metastasis (OR 13.14; 95% CI 1.57-109.94; P = 0.004) than patients with CYP2D6*1/*1 and *1/*10 genotypes. Patients with homozygous CC genotypes of ABCB1 C3435T showed a shorter time to recurrence. Patients who were CYP2D6 IM and homozygous CC genotype of C3435T have statistically significant higher risks of recurrence (P = 0.002). Similarly, median time to recurrence in these patients was only 12 months (95% CI = 0.79-23.2) compared to those without this combination which was 48 months (95% CI = 14.7-81.2). Patients with CYP2D6 IM and homozygous CC genotype of ABCB1 C3435T have shorter times to recurrence. The results confirmed the findings of previous studies and support FDA recommendation to perform pre-genotyping in patients before the choice of therapy is determined in breast cancer patients.
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Affiliation(s)
- L K Teh
- Pharmacogenomics Centre, Faculty of Pharmacy, Universiti Teknologi MARA, Campus Puncak Alam, Selangor Darul Ehsan, Malaysia.
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Cavallari LH, Jeong H, Bress A. Role of cytochrome P450 genotype in the steps toward personalized drug therapy. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2011; 4:123-36. [PMID: 23226058 PMCID: PMC3513224 DOI: 10.2147/pgpm.s15497] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Indexed: 12/19/2022]
Abstract
Genetic polymorphism for cytochrome 450 (P450) enzymes leads to interindividual variability in the plasma concentrations of many drugs. In some cases, P450 genotype results in decreased enzyme activity and an increased risk for adverse drug effects. For example, individuals with the CYP2D6 loss-of-function genotype are at increased risk for ventricular arrhythmia if treated with usual does of thioridazine. In other cases, P450 genotype may influence the dose of a drug required to achieve a desired effect. This is the case with warfarin, with lower doses often necessary in carriers of a variant CYP2C9*2 or *3 allele to avoid supratherapeutic anticoagulation. When a prodrug, such as clopidogrel or codeine, must undergo hepatic biotransformation to its active form, a loss-of-function P450 genotype leads to reduced concentrations of the active drug and decreased drug efficacy. In contrast, patients with multiple CYP2D6 gene copies are at risk for opioid-related toxicity if treated with usual doses of codeine-containing analgesics. At least 25 drugs contain information in their US Food and Drug Administration-approved labeling regarding P450 genotype. The CYP2C9, CYP2C19, and CYP2D6 genes are the P450 genes most often cited. To date, integration of P450 genetic information into clinical decision making is limited. However, some institutions are beginning to embrace routine P450 genotyping to assist in the treatment of their patients. Genotyping for P450 variants may carry less risk for discrimination compared with genotyping for disease-associated variants. As such, P450 genotyping is likely to lead the way in the clinical implementation of pharmacogenomics. This review discusses variability in the CYP2C9, CYP2C19, and CYP2D6 genes and the implications of this for drug efficacy and safety.
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Affiliation(s)
- Larisa H Cavallari
- Department of Pharmacy Practice ; Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
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23
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Morrow PK, Serna R, Broglio K, Pusztai L, Nikoloff DM, Hillman GR, Fontecha M, Li R, Michaud L, Hortobagyi G, Gonzalez-Angulo AM. Effect of CYP2D6 polymorphisms on breast cancer recurrence. Cancer 2011; 118:1221-7. [DOI: 10.1002/cncr.26407] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/06/2011] [Accepted: 06/10/2011] [Indexed: 11/11/2022]
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Abstract
Medico-legal autopsy is the primary method in determining the cause and manner of death when the death is suspected to be unnatural. In some of these autopsies, the death remains ambiguous, even after a complete autopsy including histological investigation and toxicological screenings. In cases where there are no morphological abnormalities, medico-legal genetics may offer additional means to provide knowledge of possible genetic mutations, which may have initiated the process or predisposed the individual to stress risk conditions leading to death. One class of ambiguous deaths consists of drug-related deaths where the interpretation of the toxicological results are not clear. In such situations post mortem genotyping and the analysis of metabolite rations may provide an insight to the findings. A few cases demonstrating the potential strength of pharmacogenetics in medico-legal context has been published. However, there is a paramount need for serious scientific studies before the field of post mortem pharmacogenetics can be utilized in routine medico-legal analyses casework and brought routinely into courtroom.
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Affiliation(s)
- A Sajantila
- Hjelt Institute, Department of Forensic Medicine, P.O. Box 14, University of Helsinki, Finland.
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25
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Aitchison K, Datla K, Rooprai H, Fernando J, Dexter D. Regional distribution of clomipramine and desmethylclomipramine in rat brain and peripheral organs on chronic clomipramine administration. J Psychopharmacol 2010; 24:1261-8. [PMID: 19553387 DOI: 10.1177/0269881109105789] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The tricyclic antidepressant (TCA) clomipramine has been widely used in psychiatry for over 40 years. More recently, its therapeutic potential as an antineoplastic drug has been identified. However, there are no prior data on regional distribution in the brain of clomipramine and its primary metabolite (desmethylclomipramine) after chronic oral administration. The aim of this study was to determine the concentrations of clomipramine and desmethylclomipramine in different rat-brain regions and to compare those with levels in plasma and peripheral organs after chronic oral treatment of Sprague Dawley rats (15 mg/kg) for 14 days. The levels of both parent TCA and metabolite were analysed by high-performance liquid chromatography in six brain regions (cortex, hypothalamus, hippocampus, striatum, brainstem and cerebellum), five peripheral organs and in plasma. Our data show that the cerebral cortex had the highest concentration of clomipramine (2.9 microg/mg), with successively lower concentrations in the hypothalamus, striatum, cerebellum, hippocampus and brainstem. Of the peripheral organs, the lungs and liver, had the highest levels of clomipramine, while in the heart, only the metabolite was detected. The plasma concentration (0.17 microg/ml or 0.48 microM) was comparable to that in the hippocampus and cerebellum (approximately 0.20 microg/mg). The differential distribution of clomipramine in different brain regions and the regional variation in clomipramine to desmethylclomipramine ratios have implications for the use of clomipramine in psychiatry and neuro-oncology.
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Affiliation(s)
- K Aitchison
- Institute of Psychiatry at King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, London, UK.
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26
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Squassina A, Manchia M, Manolopoulos VG, Artac M, Lappa-Manakou C, Karkabouna S, Mitropoulos K, Zompo MD, Patrinos GP. Realities and expectations of pharmacogenomics and personalized medicine: impact of translating genetic knowledge into clinical practice. Pharmacogenomics 2010; 11:1149-67. [DOI: 10.2217/pgs.10.97] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The implementation of genetic data for a better prediction of response to medications and adverse drug reactions is becoming a reality in some clinical fields. However, to be successful, personalized medicine should take advantage of an informational structured framework of genetic, phenotypic and environmental factors in order to provide the healthcare system with useful tools that can optimize the effectiveness of specific treatment. The impact of personalized medicine is potentially enormous, but the results that have so far been gathered are often difficult to translate into clinical practice. In this article we have summarized the most relevant applications of pharmacogenomics on diseases to which they have already been applied and fields in which they are currently emerging. The article provides an overview of the opportunities and shortcomings of the implementation of genetic information into personalized medicine and its full adoption in the clinic. In the second instance, it provides readers from different fields of expertise with an accessible interpretation to the barriers and opportunities in the use/adoption of pharmacogenomic testing between the different clinical areas.
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Affiliation(s)
| | - Mirko Manchia
- University of Cagliari, Cagliari, Italy
- Dalhousie University, Halifax, Nova Scotia, Canada
| | | | | | | | | | | | | | - George P Patrinos
- University of Patras, Department of Pharmacy, School of Health Sciences, University Campus, Rion, GR-265 04, Patras, Greece
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Ingelman-Sundberg M, Sim SC. Pharmacogenetic biomarkers as tools for improved drug therapy; emphasis on the cytochrome P450 system. Biochem Biophys Res Commun 2010; 396:90-4. [PMID: 20494117 DOI: 10.1016/j.bbrc.2010.02.162] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 02/24/2010] [Indexed: 11/19/2022]
Abstract
Important interindividual differences in drug pharmacokinetics cause absence of drug response or adverse drug reactions in significant fractions of the populations. The identification of the major enzymes participating, and the elucidation of the genetic basis for this variation in particular among cytochromes P450, provide tools for a personalized medicine treatment, which can make drug therapy much more effective at a lower cost. Much of the pioneering work linking drug metabolizing phenotype to genetic polymorphism among the P450 enzymes has been carried out at Karolinska Institutet. In this review we give a background and description of this work as well as the important implications for future medicine.
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Affiliation(s)
- Magnus Ingelman-Sundberg
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden.
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28
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Kalari KR, Hebbring SJ, Chai HS, Li L, Kocher JPA, Wang L, Weinshilboum RM. Copy number variation and cytidine analogue cytotoxicity: a genome-wide association approach. BMC Genomics 2010; 11:357. [PMID: 20525348 PMCID: PMC2894803 DOI: 10.1186/1471-2164-11-357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 06/04/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The human genome displays extensive copy-number variation (CNV). Recent discoveries have shown that large segments of DNA, ranging in size from hundreds to thousands of nucleotides, are either deleted or duplicated. This CNV may encompass genes, leading to a change in phenotype, including drug response phenotypes. Gemcitabine and 1-beta-D-arabinofuranosylcytosine (AraC) are cytidine analogues used to treat a variety of cancers. Previous studies have shown that genetic variation may influence response to these drugs. In the present study, we set out to test the hypothesis that variation in copy number might contribute to variation in cytidine analogue response phenotypes. RESULTS We used a cell-based model system consisting of 197 ethnically-defined lymphoblastoid cell lines for which genome-wide SNP data were obtained using Illumina 550 and 650 K SNP arrays to study cytidine analogue cytotoxicity. 775 CNVs with allele frequencies > 1% were identified in 102 regions across the genome. 87/102 of these loci overlapped with previously identified regions of CNV. Association of CNVs with gemcitabine and AraC IC50 values identified 11 regions with permutation p-values < 0.05. Multiplex ligation-dependent probe amplification assays were performed to verify the 11 CNV regions that were associated with this phenotype; with false positive and false negative rates for the in-silico findings of 1.3% and 0.04%, respectively. We also had basal mRNA expression array data for these same 197 cell lines, which allowed us to quantify mRNA expression for 41 probesets in or near the CNV regions identified. We found that 7 of those 41 genes were highly expressed in our lymphoblastoid cell lines, and one of the seven genes (SMYD3) that was significant in the CNV association study was selected for further functional experiments. Those studies showed that knockdown of SMYD3, in pancreatic cancer cell lines increased gemcitabine and AraC resistance during cytotoxicity assay, consistent with the results of the association analysis. CONCLUSIONS These results suggest that CNVs may play a role in variation in cytidine analogue effect. Therefore, association studies of CNVs with drug response phenotypes in cell-based model systems, when paired with functional characterization, might help to identify CNV that contributes to variation in drug response.
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Affiliation(s)
- Krishna R Kalari
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.
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Fluconazole-induced intoxication with phenytoin in a patient with ultra-high activity of CYP2C9. Eur J Clin Pharmacol 2010; 66:791-5. [PMID: 20405111 DOI: 10.1007/s00228-010-0820-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 03/26/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE The cytochrome P450 enzyme CYP2C9 metabolizes several important drugs, such as warfarin and oral antidiabetic drugs. The enzyme is polymorphic, and all known alleles, for example, CYP2C9*2 and*3, give decreased activity. Ultra-high activity of the enzyme has not yet been reported. METHODS We present a patient with Behçet's disease who required treatment with high doses of phenytoin. When fluconazole, a potent inhibitor of CYP2C9, was added to the treatment regimen, the patient developed ataxia, tremor, fatigue, slurred speech and somnolence, indicating phenytoin intoxication. On suspicion of ultra-high activity of CYP2C9, a phenotyping test for CYP2C9 with losartan was performed. RESULTS The patient was shown to have a higher activity of CYP2C9 than any of the 190 healthy Swedish Caucasians used as controls. CONCLUSIONS Our finding of an ultrarapid metabolism of losartan and phenytoin may apply to other CYP2C9 substrates, where inhibition of CYP2C9 may cause severe adverse drug reactions.
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Zackrisson AL, Lindblom B, Ahlner J. High frequency of occurrence of CYP2D6 gene duplication/multiduplication indicating ultrarapid metabolism among suicide cases. Clin Pharmacol Ther 2009; 88:354-9. [PMID: 19907421 DOI: 10.1038/clpt.2009.216] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In Sweden, about 550 individuals die every year of drug intoxication. Many of these drugs are metabolized by CYP enzymes such as CYP2D6 and CYP2C19. A lack of these enzymes, resulting in poor metabolism, can lead to adverse reactions and even to fatality. On the other hand, an ultrarapid metabolism can lead to insufficient drug plasma concentration, resulting in failure of treatment, or it can lead to high concentrations of active/toxic metabolites. The aim of this project was to study the genetic profile of individuals with regard to the presence of CYP2D6 and CYP2C19 genes, in cases of fatal intoxication (242), suicide (intoxications excluded) (262), and natural death (212). PCR, followed by pyrosequencing, was used for all the analyses. We found that, among those who died of suicide (suicide cases), there was a higher number carrying more than two active CYP2D6 genes (corresponding to the phenotype of ultrarapid metabolizer) as compared with those who died of natural causes (natural-death cases) (P = 0.007).
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Affiliation(s)
- A L Zackrisson
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
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32
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Affiliation(s)
- Shu-Feng Zhou
- Discipline of Chinese Medicine, School of Health Sciences, RMIT University, Victoria, Australia.
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33
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Zhou SF, Liu JP, Chowbay B. Polymorphism of human cytochrome P450 enzymes and its clinical impact. Drug Metab Rev 2009; 41:89-295. [PMID: 19514967 DOI: 10.1080/03602530902843483] [Citation(s) in RCA: 502] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.
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Affiliation(s)
- Shu-Feng Zhou
- School of Health Sciences, RMIT University, Bundoora, Victoria, Australia.
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Brauch H, Jordan VC. Targeting of tamoxifen to enhance antitumour action for the treatment and prevention of breast cancer: The ‘personalised’ approach? Eur J Cancer 2009; 45:2274-83. [DOI: 10.1016/j.ejca.2009.05.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 05/22/2009] [Indexed: 12/13/2022]
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Bijl MJ, Luijendijk HJ, van den Berg JF, Visser LE, van Schaik RHN, Hofman A, Vulto AG, van Gelder T, Tiemeier H, Stricker BHC. Association between the CYP2D6*4 polymorphism and depression or anxiety in the elderly. Pharmacogenomics 2009; 10:541-7. [PMID: 19374513 DOI: 10.2217/pgs.09.9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION 5-methoxytryptamine (5-MT), a precursor of serotonin, is considered to be an endogenous substrate of cytochrome P450 2D6 (CYP2D6). Homozygous carriers of the variant allele CYP2D6*4 lack CYP2D6 enzyme activity. Relative to extensive metabolizers, these poor metabolizers may have lower baseline serotonin concentrations in various brain regions, and may be more prone to depression or anxiety. AIM To test whether the CYP2D6*4/*4 genotype is associated with a predisposition to depression or anxiety disorders in the elderly. MATERIALS & METHODS We conducted a cross-sectional study within the Rotterdam Study, a population-based cohort study, among persons aged 55 years or older, who were screened for depression and anxiety disorders at two consecutive examination rounds. Logistic regression was used to analyze the association between the CYP2D6*4 polymorphism and the risk of depression or anxiety disorders. RESULTS The risk of major depression in CYP2D6*4/*4 was not significantly different from extensive metabolizers (OR = 0.85; 95% CI: 0.36-2.00; p = 0.72). Neither did we find an association between CYP2D6 genotype and minor depression (OR = 1.56; 95% CI: 0.69-3.52; p = 0.28). No increased risk of anxiety disorders was found (OR = 1.19; 95% CI: 0.68-2.09; p = 0.55). CONCLUSION Variation in the CYP2D6 gene is not related to a predisposition to depression or anxiety disorders in the elderly.
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Affiliation(s)
- Monique J Bijl
- Erasmus Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
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Overbeek A, Lambalk CB. Phenotypic and pharmacogenetic aspects of ovulation induction in WHO II anovulatory women. Gynecol Endocrinol 2009; 25:222-34. [PMID: 19408171 DOI: 10.1080/09513590802571118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Because of an enormous increase in pharmacogenetic and -genomic knowledge, an era of predicting drug response on the basis of one's genome is drawing close to reality. Anovulation is the most common cause of infertility, and outcomes of treatment are often unpredictable. This review aims to summarise in what way genetic variability might modify effects of drug-metabolising enzymes, transporters and receptors, thereby altering response to drugs used in ovulation induction.
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Affiliation(s)
- Annelies Overbeek
- Department of Obstetrics and Gynaecology, Division of Reproductive Medicine, VU University Medical Centre, Amsterdam, The Netherlands.
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Gareri P, De Fazio P, Russo E, Marigliano N, De Fazio S, De Sarro G. The safety of clozapine in the elderly. Expert Opin Drug Saf 2008; 7:525-38. [PMID: 18759705 DOI: 10.1517/14740338.7.5.525] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Clozapine was the first atypical 'broad spectrum' antipsychotic drug to be marketed and the first agent approved for the treatment of schizophrenia refractory to other medications. It is also effective for the treatment of aggressive behaviour in schizophrenic and demented patients and in the management of psychosis and aggression in Parkinson's disease and Lewy body dementia. OBJECTIVE The aim of this review is to study the safety of clozapine for use in elderly patients. METHODS An extensive Medline search was made. Some studies that were referenced in reports from our pharmacovigilance centre and from regulatory agencies such as the FDA, EMEA and WHO were included. CONCLUSIONS Clozapine treatment in the elderly requires a careful geriatric assessment. However, its use is strongly limited by the possibility of onset of severe adverse effects such as potentially fatal agranulocytosis, myocarditis and others such as seizures, weight gain and metabolic adverse effects.
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Affiliation(s)
- Pietro Gareri
- University "Magna Graecia" of Catanzaro, "Mater Domini" University Hospital, Clinical Pharmacology and Pharmacovigilance Unit, Faculty of Medicine and Surgery, Department of Experimental and Clinical Medicine, Catanzaro, Italy.
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Non-response to consecutive antidepressant therapy caused by CYP2D6 ultrarapid metabolizer phenotype. Int J Neuropsychopharmacol 2008; 11:727-8. [PMID: 18384706 DOI: 10.1017/s1461145708008742] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Katz DA, Murray B, Bhathena A, Sahelijo L. Defining drug disposition determinants: a pharmacogenetic-pharmacokinetic strategy. Nat Rev Drug Discov 2008; 7:293-305. [PMID: 18382463 DOI: 10.1038/nrd2486] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In preclinical and early clinical drug development, information about the factors influencing drug disposition is used to predict drug interaction potential, estimate and understand population pharmacokinetic variability, and select doses for clinical trials. However, both in vitro drug metabolism studies and pharmacogenetic association studies on human pharmacokinetic parameters have focused on a limited subset of the proteins involved in drug disposition. Furthermore, there has been a one-way information flow, solely using results of in vitro studies to select candidate genes for pharmacogenetic studies. Here, we propose a two-way pharmacogenetic-pharmacokinetic strategy that exploits the dramatic recent expansion in knowledge of functional genetic variation in proteins that influence drug disposition, and discuss how it could improve drug development.
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Affiliation(s)
- David A Katz
- Abbott Global Pharmaceutical Research & Development, 100 Abbott Park Road, Abbott Park, Illinois 60064-3500, USA.
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Ingelman-Sundberg M, Sim SC, Gomez A, Rodriguez-Antona C. Influence of cytochrome P450 polymorphisms on drug therapies: pharmacogenetic, pharmacoepigenetic and clinical aspects. Pharmacol Ther 2007; 116:496-526. [PMID: 18001838 DOI: 10.1016/j.pharmthera.2007.09.004] [Citation(s) in RCA: 757] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 09/20/2007] [Indexed: 01/11/2023]
Abstract
The polymorphic nature of the cytochrome P450 (CYP) genes affects individual drug response and adverse reactions to a great extent. This variation includes copy number variants (CNV), missense mutations, insertions and deletions, and mutations affecting gene expression and activity of mainly CYP2A6, CYP2B6, CYP2C9, CYP2C19 and CYP2D6, which have been extensively studied and well characterized. CYP1A2 and CYP3A4 expression varies significantly, and the cause has been suggested to be mainly of genetic origin but the exact molecular basis remains unknown. We present a review of the major polymorphic CYP alleles and conclude that this variability is of greatest importance for treatment with several antidepressants, antipsychotics, antiulcer drugs, anti-HIV drugs, anticoagulants, antidiabetics and the anticancer drug tamoxifen. We also present tables illustrating the relative importance of specific common CYP alleles for the extent of enzyme functionality. The field of pharmacoepigenetics has just opened, and we present recent examples wherein gene methylation influences the expression of CYP. In addition microRNA (miRNA) regulation of P450 has been described. Furthermore, this review updates the field with respect to regulatory initiatives and experience of predictive pharmacogenetic investigations in the clinics. It is concluded that the pharmacogenetic knowledge regarding CYP polymorphism now developed to a stage where it can be implemented in drug development and in clinical routine for specific drug treatments, thereby improving the drug response and reducing costs for drug treatment.
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Affiliation(s)
- Magnus Ingelman-Sundberg
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177, Stockholm, Sweden.
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Bertilsson L. Metabolism of antidepressant and neuroleptic drugs by cytochrome p450s: clinical and interethnic aspects. Clin Pharmacol Ther 2007; 82:606-9. [PMID: 17898711 DOI: 10.1038/sj.clpt.6100358] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Early after the introduction of the classical tricyclic antidepressants and neuroleptics, it was shown that the plasma concentrations of these drugs varied between patients given the same dose. This variation is to a major extent due to the variation in the activity of cytochrome P450 (CYP) enzymes (cf. review by Bertilsson et al.1) During recent year(s), the different CYP enzymes catalyzing the metabolism of these drugs have been identified and the clinical relevance has also been identified. This brief review highlights the clinical importance and ethnic differences in the metabolism of these drugs.
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Affiliation(s)
- L Bertilsson
- Division of Clinical Pharmacology, Department of Laboratory Medicine at Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
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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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Hebbring SJ, Adjei AA, Baer JL, Jenkins GD, Zhang J, Cunningham JM, Schaid DJ, Weinshilboum RM, Thibodeau SN. Human SULT1A1 gene: copy number differences and functional implications. Hum Mol Genet 2006; 16:463-70. [PMID: 17189289 DOI: 10.1093/hmg/ddl468] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
SULT1A1, which catalyzes the sulfate conjugation of a wide variety of natural and synthetic compounds, is genetically polymorphic. Biochemical and pharmacogenetic studies have demonstrated that individual variation in the level of enzyme activity is inherited. Common single-nucleotide polymorphisms (SNPs) located in the open reading frame and in the 5'-flanking region (5'-FR) may account for a portion of this individual variation. In this study, we demonstrate the presence of SULT1A1 gene deletions and duplications, representing an additional source of variability in the metabolic activity of this enzyme. A quantitative multiplex PCR assay was used to measure the extent of copy number differences and the frequency of these events in different populations. An analysis of DNA from 362 Caucasian-American and 99 African-American showed the presence of 1 to approximately 5 copies of SULT1A1 in individual samples: 5% of Caucasian subjects contained a single copy of the gene and 26% had three or more copies, while 63% of African-American subjects had three or more copies. Analysis of the genomic region surrounding the SULT1A1 gene in three separate cases with a deletion demonstrated that the entire SULT1A1 gene was affected. Reporter assays, constructed for each of the various 5'-FR SNP haplotypes, suggest that these may also play a role in SULT1A1 activity. However, the variability in the level of enzyme activity among 23 human platelet and 267 human liver samples was best explained by gene copy number differences when all sources of genetic variability were considered (P < 0.0001). Overall, these observations have obvious implications for the effectiveness of SULT1A1 as a drug and hormone metabolizing enzyme and its potential role as a risk factor for disease.
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Affiliation(s)
- Scott J Hebbring
- Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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de Leon J, Susce MT, Murray-Carmichael E. The AmpliChip CYP450 genotyping test: Integrating a new clinical tool. Mol Diagn Ther 2006; 10:135-51. [PMID: 16771600 DOI: 10.1007/bf03256453] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The AmpliChip CYP450 Test, which analyzes patient genotypes for cytochrome P450 (CYP) genes CYP2D6 and CYP2C19, is a major step toward introducing personalized prescribing into the clinical environment. Interest in adverse drug reactions (ADRs), the genetic revolution, and pharmacogenetics have converged with the introduction of this tool, which is anticipated to be the first of a new wave of such tools to follow over the next 5-10 years. The AmpliChip CYP450 Test is based on microarray technology, which combines hybridization in precise locations on a glass microarray and a fluorescent labeling system. It classifies individuals into two CYP2C19 phenotypes (extensive metabolizers [EMs] and poor metabolizers [PMs]) by testing three alleles, and into four CYP2D6 phenotypes (ultrarapid metabolizers [UMs], EMs, intermediate metabolizers [IMs], and PMs) by testing 27 alleles, including seven duplications. CYP2D6 is a metabolic enzyme with four activity levels (or phenotypes): UMs with unusually high activity; normal subjects, known as EMs; IMs with low activity; and PMs with no CYP2D6 activity (7% of Caucasians and 1-3% in other ethnic groups). Levels of evidence for the association between CYP2D6 PMs and ADRs are relatively reasonable and include systematic reviews of case-control studies of some typical antipsychotics and tricyclic antidepressants (TCAs). Evidence for other phenotypes is considerably more limited. The CYP2D6 PM phenotype may be associated with risperidone ADRs and discontinuation due to ADRs. Venlafaxine, aripiprazole, duloxetine, and atomoxetine are newer drugs metabolized by CYP2D6 but studies of the clinical relevance of CYP2D6 genotypes are needed. Non-psychiatric drugs metabolized by CYP2D6 include metoprolol, tamoxifen, and codeine-like drugs. CYP2C19 PMs (3-4% of Caucasians and African Americans, and 14-21% of Asians) may require dose adjustment for some TCAs, moclobemide, and citalopram. Other drugs metabolized by CYP2C19 are diazepam and omeprazole. The future of pharmacogenetics depends on the ability to overcome serious obstacles, including the difficulties of conducting and publishing studies in light of resistance from grant agencies, pharmaceutical companies, and some scientific reviewers. Assuming more studies are published, pharmacogenetic clinical applications may be compromised by economic factors and the lack of physician education. The combination of a US FDA-approved test, such as the AmpliChip CYP450 Test, and an FDA definition of CYP2D6 as a 'valid biomarker' makes CYP2D6 genotyping a prime candidate to be the first successful pharmacogenetic test in the clinical environment. One can use microarray technology to test for hundreds of single nucleotide polymorphisms (SNPs) but, taking into account the difficulties for single gene approaches such as CYP2D6, it is unlikely that very complex pharmacogenetic approaches will reach the clinical market in the next 5-10 years.
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Affiliation(s)
- Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, Kentucky 40508, USA.
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Thuerauf N, Lunkenheimer J. The impact of the CYP2D6-polymorphism on dose recommendations for current antidepressants. Eur Arch Psychiatry Clin Neurosci 2006; 256:287-93. [PMID: 16783493 DOI: 10.1007/s00406-006-0663-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cytochrome P450 CYP2D6 represents an extensively characterized polymorphic drug-metabolizing enzyme. The CYP2D6-gene is highly polymorphic and more than 70 different alleles are known currently. The activity of the enzyme markedly varies among individuals from poor to intermediate and extensive up to ultrarapid metabolism on the basis of the polymorphism of the CYP2D6 gene. Association studies provide growing evidence for the clinical importance of the CYP2D6 polymorphism investigating whether the CYP2D6 genotype distribution differs from that of the normal population either in patients with marked adverse effects or in nonresponders during treatment with CYP2D6 substrates. However, these scientifically important studies present less information for dose adjustments necessary to individualize pharmacotherapy in a given clinical case. With respect to psychopharmacological drug metabolism several antidepressants were characterized as being CYP2D6 substrates. Thus, this review summarizes dose recommendations of current antidepressants.
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Affiliation(s)
- Norbert Thuerauf
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Univeristy of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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Juran BD, Egan LJ, Lazaridis KN. The AmpliChip CYP450 test: principles, challenges, and future clinical utility in digestive disease. Clin Gastroenterol Hepatol 2006; 4:822-30. [PMID: 16797246 DOI: 10.1016/j.cgh.2006.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Understanding genetically encoded inherited differences in drug metabolism and targets (ie, receptors, transporters) offers the promise of minimizing adverse drug reactions and improving therapies. Among the enzymes involved in drug metabolism, the cytochromes P450 (CYP450) hold a central position. In fact, CYP450 are involved in the biotransformation of most drugs used in clinical practice. Recent advances in the development of DNA-based diagnostics, coupled with a better understanding of genetic polymorphisms in influencing pharmacologic responses, have provided the foundation for novel in vitro tests that may predict side effects and/or therapeutic responses. The AmpliChip CYP450 test was developed as a clinical test to evaluate an individual's metabolic capacity for certain drugs by identifying polymorphisms of 2 CYP450 enzymes (ie, CYP2D6 and CYP2D19). Even though the AmpliChip CYP450 has been approved by the US Food and Drug Administration, its practical clinical utility has not yet been determined, and there is a paucity of data related to gastrointestinal and liver diseases. An understanding of the principles and opportunities provided by this new category of diagnostic test is key before planning the necessary studies to evaluate the usefulness of AmpliChip CYP450 in gastroenterologic clinical practice.
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Affiliation(s)
- Brian D Juran
- Center for Basic Research in Digestive Diseases, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Ozdemir V, Aklillu E, Mee S, Bertilsson L, Albers LJ, Graham JE, Caligiuri M, Lohr JB, Reist C. Pharmacogenetics for off-patent antipsychotics: reframing the risk for tardive dyskinesia and access to essential medicines. Expert Opin Pharmacother 2006; 7:119-33. [PMID: 16433578 DOI: 10.1517/14656566.7.2.119] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
First-generation antipsychotics (FGAs) induce tardive dyskinesia, a debilitating involuntary hyperkinetic movement disorder, in 20-50% of individuals with a psychotic illness during chronic treatment. There is presently no curative treatment or definitive predictive test for tardive dyskinesia. The authors note that the three antipsychotic drugs enlisted in the most recent (14th) World Health Organization Model List of Essential Medicines--chlorpromazine, fluphenazine and haloperidol--belong to the FGA therapeutic class. In this regard, the need to choose between the competing objectives of ensuring global access to affordable and efficacious medicines, such as FGAs, and the formidable long-term risk for tardive dyskinesia, may create an ethical conundrum. Pharmacogenetics has thus far been conceptually framed as a tool to individualize therapy with new drugs under patent protection. However, the authors suggest that pharmacogenetics may also improve access to pharmacotherapy through the reintroduction of affordable second-line generic drugs or FGAs with suboptimal safety, as first-line therapy, in targeted subpopulations in whom they present a lower risk for tardive dyskinesia. To impact positively on global public health and distributive justice, a directory complementary to the essential medicines library--one that enlists the 'essential biomarkers' required for optimal pharmacotherapy--may benefit patients who do not have adequate access to new antipsychotic medications. This review discusses pharmacogenetic associations of tardive dyskinesia that are in part supported by meta-analyses and the oxidative stress-neuronal degeneration hypothesis.
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Affiliation(s)
- Vural Ozdemir
- VA Long Beach Healthcare System, Southern California Institute for Research and Education, Department of Psychiatry and Human Behavior, College of Medicine, University of California, Irvine, Long Beach, CA 90822, USA.
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Sabbagh A, Darlu P. Data-Mining Methods as Useful Tools for Predicting Individual Drug Response: Application to CYP2D6 Data. Hum Hered 2006; 62:119-34. [PMID: 17057402 DOI: 10.1159/000096416] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 08/22/2006] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Selecting a maximally informative subset of polymorphisms to predict a clinical outcome, such as drug response, requires appropriate search methods due to the increased dimensionality associated with looking at multiple genotypes. In this study, we investigated the ability of several pattern recognition methods to identify the most informative markers in the CYP2D6 gene for the prediction of CYP2D6 metabolizer status. METHODS Four data-mining tools were explored: decision trees, random forests, artificial neural networks, and the multifactor dimensionality reduction (MDR) method. Marker selection was performed separately in eight population samples of different ethnic origin to evaluate to what extent the most informative markers differ across ethnic groups. RESULTS Our results show that the number of polymorphisms required to predict CYP2D6 metabolic phenotype with a high accuracy can be dramatically reduced owing to the strong haplotype block structure observed at CYP2D6. MDR and neural networks provided nearly identical results and performed the best. CONCLUSION Data-mining methods, such as MDR and neural networks, appear as promising tools to improve the efficiency of genotyping tests in pharmacogenetics with the ultimate goal of pre-screening patients for individual therapy selection with minimum genotyping effort.
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Affiliation(s)
- Audrey Sabbagh
- Unité de Recherche en Génétique Epidémiologique et Structure des Populations Humaines, INSERM U535, Villejuif, France.
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Ingelman-Sundberg M. Genetic polymorphisms of cytochrome P450 2D6 (CYP2D6): clinical consequences, evolutionary aspects and functional diversity. THE PHARMACOGENOMICS JOURNAL 2005; 5:6-13. [PMID: 15492763 DOI: 10.1038/sj.tpj.6500285] [Citation(s) in RCA: 726] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
CYP2D6 is of great importance for the metabolism of clinically used drugs and about 20-25% of those are metabolised by this enzyme. In addition, the enzyme utilises hydroxytryptamines as endogenous substrates. The polymorphism of the enzyme results in poor, intermediate, efficient or ultrarapid metabolisers (UMs) of CYP2D6 drugs. It is plausible that the UM genotype, where more than one active gene on one allele occurs, is the outcome of selective dietary selection in certain populations in North East Africa. The UM phenotype affects 5.5% of the population in Western Europe. A hypothesis for the evolutionary basis behind selection for CYP2D6 gene duplications is presented in relation to selection for Cyp6 variants in insecticide resistant Drosophila strains. The polymorphism of CYP2D6 significantly affects the pharmacokinetics of about 50% of the drugs in clinical use, which are CYP2D6 substrates. The consequences of the polymorphism at ordinary drug doses can be either adverse drug reactions or no drug response. Examples are presented where CYP2D6 polymorphism affects the efficacy and costs of drug treatment. Predictive CYP2D6 genotyping is estimated by the author to be beneficial for treatment of about 30-40% of CYP2D6 drug substrates, that is, for about 7-10% of all drugs clinically used, although prospective clinical studies are necessary to evaluate the exact benefit of drug selection and dosage based on the CYP2D6 genotype.
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Affiliation(s)
- M Ingelman-Sundberg
- Division of Molecular Toxicology, IMM, Karolinska Institutet, Stockholm, Sweden.
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Steimer W, Zöpf K, von Amelunxen S, Pfeiffer H, Bachofer J, Popp J, Messner B, Kissling W, Leucht S. Amitriptyline or Not, That Is the Question: Pharmacogenetic Testing of CYP2D6 and CYP2C19 Identifies Patients with Low or High Risk for Side Effects in Amitriptyline Therapy. Clin Chem 2005; 51:376-85. [PMID: 15590749 DOI: 10.1373/clinchem.2004.041327] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground: Amitriptyline has been replaced in many countries by alternative and more expensive drugs based on claims of improved tolerability and toxicity and despite slightly reduced efficacy. Preliminary studies indicate that adverse effects could be linked to polymorphisms of drug-metabolizing enzymes, but information on their clinical impact remains scanty and includes mainly case reports. We conducted a prospective blinded two-center study seeking correlations between CYP2C19 and CYP2D6 genotypes, drug concentrations, adverse events, and therapy response.Methods: Fifty Caucasian inpatients with at least medium-grade depressive disorder received amitriptyline at a fixed dose of 75 mg twice a day. Blood samples for concentration monitoring of amitriptyline and nortriptyline were taken weekly until discharge along with evaluations of depression (Hamilton Depression Scale and Clinical Global Impression Scale) and side effect (Dosage Record and Treatment Emergent Symptoms Scale; DOTES) scores.Results: In a ROC analysis, nortriptyline but not amitriptyline concentrations correlated with side effects (DOTES sum score ≥5; area under the curve, 0.733; P = 0.008). Carriers of two functional CYP2D6 alleles had a significantly lower risk of side effects than carriers of only one functional allele (12.1% vs 76.5%; P = 0.00001). The lowest risk was observed for carriers of two functional CYP2D6 alleles combined with only one functional CYP2C19 allele [0 of 13 (0%) vs 9 of 11 (81.8%) for the high-risk group; P = 0.00004]. We found no correlations between drug concentrations or genotypes and therapeutic response.Conclusions: Combined pharmacogenetic testing for CYP2D6 and CYP2C19 identifies patients with low risk for side effects in amitriptyline therapy and could possibly be used to individualize antidepressive regimens and reduce treatment cost. Identification of genotypes associated with slightly reduced intermediate metabolism may be more important than currently anticipated. It could also be the key to demonstrating cost-effectiveness for CYP2D6 genotyping in critical dose drugs.
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Affiliation(s)
- Werner Steimer
- Institut für Klinische Chemie und Pathobiochemie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
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