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Albitar O, Harun SN, Sheikh Ghadzi SM. Semi-physiological Pharmacokinetic Model of Clozapine and Norclozapine in Healthy, Non-smoking Volunteers: The Impact of Race and Genetics. CNS Drugs 2024; 38:571-581. [PMID: 38836990 DOI: 10.1007/s40263-024-01092-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/17/2024] [Indexed: 06/06/2024]
Abstract
BACKGROUND AND OBJECTIVES: Clozapine is the medication of choice for treatment-resistant schizophrenia. However, it has a complex metabolism and unexplained interindividual variability. The current work aims to develop a pharmacokinetic model of clozapine and norclozapine in non-smokers and assess the impact of demographic and genetic predictors. METHODS Healthy volunteers were recruited in a population pharmacokinetic study. Blood samples were collected at 30 min and 1, 2, 3, 5 and 8 h following a single flat dose of clozapine (12.5 mg). The clozapine and norclozapine concentrations were measured via high-performance liquid chromatography-ultraviolet method. A semi-physiological pharmacokinetic model of clozapine and norclozapine was developed using nonlinear mixed-effects modeling. Clinical and genetic predictors were evaluated, including CYP1A2 (rs762551) and ABCB1 (rs2032582), using restriction fragment length polymorphism. RESULTS A total of 270 samples were collected from 33 participants. The data were best described using a two-compartment model for clozapine and a two-compartment model for norclozapine with first-order absorption and elimination and pre-systemic metabolism. The estimated (relative standard error) clearance of clozapine and norclozapine were 27 L h-1 (31.5 %) and 19.6 L h-1 (30%), respectively. Clozapine clearance was lower in sub-Saharan Africans (n = 4) and higher in Caucasians (n = 9) than Asians (n = 20). Participants with CYP1A2 (rs762551) (n = 18) and ABCB1 (rs2032582) (n = 12) mutant alleles had lower clozapine clearance in the univariate analysis. CONCLUSIONS This is the first study to develop a semi-physiological pharmacokinetic model of clozapine and norclozapine accounting for the pre-systemic metabolism. Asians required lower doses of clozapine as compared with Caucasians, while clozapine pharmacokinetics in sub-Saharan Africans should be further investigated in larger trials.
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Affiliation(s)
- Orwa Albitar
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, 11800, Gelugor, Penang, Malaysia
- Roche Pharma Research and Early Development, Basel, Switzerland
| | - Sabariah Noor Harun
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, 11800, Gelugor, Penang, Malaysia
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Meyer JM. Making sense of norclozapine levels: 3 clinical axioms. Schizophr Res 2024; 268:289-292. [PMID: 37945386 DOI: 10.1016/j.schres.2023.10.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/27/2023] [Accepted: 10/29/2023] [Indexed: 11/12/2023]
Abstract
Laboratories commonly provide norclozapine concentrations when a plasma clozapine level is requested, but the appropriate use of this information for the treatment of individuals with schizophrenia is not always clear. Particularly vexing is the fact that norclozapine possesses pharmacological properties that are distinct from its parent compound and which contribute to clozapine's efficacy signal, yet the literature focuses primarily on the association of clozapine levels with symptomatic improvement. The purpose of this brief article is to highlight findings with respect to the need to track norclozapine levels, or the ratio of clozapine/norclozapine plasma levels, to optimize efficacy among inadequate responders to clozapine treatment. In addition, there will be a discussion of the specific type of information provided by the clozapine/norclozapine ratio on clozapine's clearance, and how this ratio is sometimes misinterpreted. There is clinical value from to be derived from norclozapine levels and the clozapine/norclozapine ratio for schizophrenia management, and the principles governing use of this information will be distilled into 3 succinct axioms to aid clinicians in managing their clozapine-treated patients with schizophrenia.
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Anand A, Kumar R, Sharma S, Gupta A, Vijayvergiya R, Mehrotra S, Kumar B, Lad D, Patil AN, Shafiq N, Malhotra S. Development and validation wise assessment of genotype guided warfarin dosing algorithm in Indian population. Drug Metab Pers Ther 2023; 38:273-279. [PMID: 37075481 DOI: 10.1515/dmpt-2022-0189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/13/2023] [Indexed: 04/21/2023]
Abstract
OBJECTIVES A study was conducted to develop and validate the warfarin pharmacogenetic dose optimization algorithm considering the clinical pharmacogenetic implementation consortium (CPIC) recommendations for the Asian ethnicity population. METHODS The present prospective observational study recruited warfarin-receiving patients. We collected a three ml blood sample for VKORC1, CYP2C9*2, CYP2C9*3, and CYP4F2 polymorphism assessment during the follow-up visits. Clinical history, sociodemographic and warfarin dose details were noted. RESULTS The study recruited 300 patients (250 in derivation and 50 in validation timed cohort) receiving warfarin therapy. The baseline characteristics were similar in both cohorts. BMI, presence of comorbidity, VKORC1, CYP2C9*2, and CYP2C9*3 were identified as covariates significantly affecting the warfarin weekly maintenance dose (p<0.001 for all) and the same were included in warfarin pharmacogenetic dose optimization algorithm building. The algorithm built-in the present study showed a good correlation with Gage (r=0.57, p<0.0001), and IWPC (r=0.51, p<0.0001) algorithms, widely accepted in western side of the globe. The receiver operating characteristic curve analysis showed a sensitivity of 73 %, a positive predictive value of 96 %, and a specificity of 89 %. The algorithm correctly identified the validation cohort's warfarin-sensitive, intermediate reacting, and resistant patient populations. CONCLUSIONS Validation and comparisons of the warfarin pharmacogenetic dose optimization algorithm have made it ready for the clinical trial assessment.
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Affiliation(s)
- Aishwarya Anand
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rupesh Kumar
- Department of Cardiothoracic and Vascular Surgery, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Swati Sharma
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Ankur Gupta
- Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rajesh Vijayvergiya
- Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Saurabh Mehrotra
- Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Basant Kumar
- Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Deepesh Lad
- Department of Clinical Hematology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Amol N Patil
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Nusrat Shafiq
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Samir Malhotra
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Demirbugen Oz M, Ozdemir F, Tok KC, Dural E, Kir Y, Ulusoy M, Gumustas M, Baskak B, Suzen HS. The potential role of por*28 and cyp1a2*f genetic variations and lifestyle factors on clozapine and n-desmethyl clozapine plasma levels in schizophrenia patients. Expert Opin Drug Metab Toxicol 2023. [PMID: 37269349 DOI: 10.1080/17425255.2023.2221849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023]
Abstract
BACKGROUND Despite its advantages over other antipsychotics, for treatment-resistant schizophrenia, clinical use of Clozapine (CLZ) is challenging by its narrow therapeutic index and potentially life-threatening dose-related adverse effects. RESEARCH DESIGN AND METHODS As the potential role in CLZ metabolism is assigned to CYP1A2 enzyme and consequently Cytochrome P450 oxidoreductase (POR) their genetic variations might help to determine CLZ levels in schizophrenia patients. For this purpose, 112 schizophrenia patients receiving CLZ were included in the current study. Plasma CLZ and N-desmethylclozapine (DCLZ) levels were analyzed by using HPLC and genetic variations were identified with the PCR-RFLP method. RESULTS The patients' CYP1A2 and POR genotypes seemed to not affect plasma CLZ and DCLZ levels whereas in the subgroup analysis, POR × 28 genotype significantly influenced simple and adjusted plasma CLZ and DLCZ levels concerning smoking habit and caffeine consumption. CONCLUSIONS The findings of the present study highlight the importance of both genetic and non-genetic factors (smoking and caffeine consumption) for the individualization of the CLZ treatment. In addition to that, it suggests that the added utility of not only the CLZ metabolizing enzymes but also POR, which is crucial for proper CYP activity, to guide CLZ dosing might be useful for clinical decision-making.
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Affiliation(s)
- Merve Demirbugen Oz
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
| | - Fezile Ozdemir
- Dr Fazil Kucuk Faculty of Medicine, Eastern Mediterranean University, North, Cyprus, Turkey
| | - Kenan Can Tok
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Emrah Dural
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Sivas Cumhuriyet University, Sivas, Turkey
| | - Yagmur Kir
- Bursa Acibadem Hospital, Department of Psychiatry, Bursa, Turkey
| | - Muge Ulusoy
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - Mehmet Gumustas
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Bora Baskak
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - H Sinan Suzen
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
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Treatment-Resistant Schizophrenia, Clozapine Resistance, Genetic Associations, and Implications for Precision Psychiatry: A Scoping Review. Genes (Basel) 2023; 14:genes14030689. [PMID: 36980961 PMCID: PMC10048540 DOI: 10.3390/genes14030689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/03/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
Treatment-resistant schizophrenia (TRS) is often associated with severe burden of disease, poor quality of life and functional impairment. Clozapine is the gold standard for the treatment of TRS, although it is also known to cause significant side effects in some patients. In view of the burgeoning interest in the role of genetic factors in precision psychiatry, we conducted a scoping review to narratively summarize the current genetic factors associated with TRS, clozapine resistance and side effects to clozapine treatment. We searched PubMed from inception to December 2022 and included 104 relevant studies in this review. Extant evidence comprised associations between TRS and clozapine resistance with genetic factors related to mainly dopaminergic and serotoninergic neurotransmitter systems, specifically, TRS and rs4680, rs4818 within COMT, and rs1799978 within DRD2; clozapine resistance and DRD3 polymorphisms, CYP1A2 polymorphisms; weight gain with LEP and SNAP-25 genes; and agranulocytosis risk with HLA-related polymorphisms. Future studies, including replication in larger multi-site samples, are still needed to elucidate putative risk genes and the interactions between different genes and their correlations with relevant clinical factors such as psychopathology, psychosocial functioning, cognition and progressive changes with treatment over time in TRS and clozapine resistance.
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Sangüesa E, Cirujeda C, Concha J, Padilla PP, García CB, Ribate MP. Pharmacokinetic interactions between clozapine and valproic acid in patients with treatment-resistant schizophrenia: Does UGT polymorphism affect these drug interactions? Chem Biol Interact 2022; 364:110042. [PMID: 35853541 DOI: 10.1016/j.cbi.2022.110042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/13/2022] [Indexed: 11/29/2022]
Abstract
The combination of valproic acid (VPA) and clozapine (CLZ) is regularly prescribed for augmentation therapy in treatment resistant schizophrenia. The VPA has been shown to reduce norclozapine (NCLZ) plasma levels, but the mechanism of this interaction remains unknown. The aim of this study is to examine the differences between patients treated with CLZ and patients treated with CLZ plus VPA. For it, various factors have been evaluated. The study was based on plasma samples from CLZ and CLZ plus VPA treated patients (n = 61) subjected to routine therapeutic drug monitoring considering clinical data, smoking status, daily dose of CLZ and VPA, concomitant medications, albumin, and renal and hepatic function. Genotyping of polymorphisms of CYP1A2, CYP3A4/5, CYP2C19, ABCB1, UGT2B10 and CYP2C19 were performed by real time PCR. CYP2D6 were genotyped using competitive allele-specific PCR and by a long PCR based method. Plasma CLZ and NCLZ concentrations were measured by Liquid Chromatography-Tandem masses (LC-MS/MS) and plasma VPA by Ultraviolet-Visible (UV-vis) spectrophotometric immunoassay. The patients presented adequate CLZ levels in relation to the dose. However, NCLZ levels were excessively low and the CLZ/NCLZ ratio very high. Patients with UGT2B10 GT (rs61750900) genotype showed lower NCLZ plasma levels and C/D NCLZ, and higher CLZ/NCLZ ratio versus patients with UGT2B10 GG genotype. VPA, smoking, the presence of UGT2B10 GT genotype and having low albumin levels indicate that the CLZ/NCLZ ratio is affected, mostly coinciding with decreased NCLZ levels and possibly with an increased risk of neutropenia.
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Affiliation(s)
- Estela Sangüesa
- Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego- Zaragoza, Spain
| | - Christine Cirujeda
- Centro Neuropsiquiátrico Nuestra Señora del Carmen, Hermanas Hospitalarias, Zaragoza, Spain
| | - Julia Concha
- Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego- Zaragoza, Spain
| | - Pedro Pablo Padilla
- Centro Neuropsiquiátrico Nuestra Señora del Carmen, Hermanas Hospitalarias, Zaragoza, Spain
| | - Cristina Belén García
- Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego- Zaragoza, Spain.
| | - María Pilar Ribate
- Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego- Zaragoza, Spain
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Sangüesa E, Cirujeda C, Concha J, Padilla PP, García CB, Ribate MP. Exploring the usefulness of plasma level determination and pharmacogenetics for patients treated with clozapine. Per Med 2022; 19:181-192. [PMID: 35259926 DOI: 10.2217/pme-2021-0029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aims: The aims of the present study were to assess the variance of plasma clozapine (CLZ) levels and to identify the influence of sociodemographic and pharmacogenetic factors on it and to introduce these tools in a clinical setting. Patients & methods: CLZ concentration was measured and genetic variants of CLZ pharmacokinetic and pharmacodynamic factors were assessed in 23 patients with psychotic disorders. Results: A significant association between mean concentration/dose ratio (C/D) and smoking status, age and weight were found. There was a significant difference in mean plasma CLZ levels and gender. The rs762551 AA genotype in smokers had a significantly lower C/D. Conclusion: In addition to classical factors, monitoring of plasma concentrations together with pharmacogenetics led to greater individualization of treatment.
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Affiliation(s)
- Estela Sangüesa
- Pharmacy degree, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Zaragoza, Spain
| | - Christine Cirujeda
- Centro Neuropsiquiátrico Nuestra Señora del Carmen. Hermanas Hospitalarias, Zaragoza, Spain
| | - Julia Concha
- Pharmacy degree, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Zaragoza, Spain
| | - Pedro Pablo Padilla
- Centro Neuropsiquiátrico Nuestra Señora del Carmen. Hermanas Hospitalarias, Zaragoza, Spain
| | - Cristina Belén García
- Pharmacy degree, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Zaragoza, Spain
| | - María Pilar Ribate
- Pharmacy degree, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Zaragoza, Spain
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Patil AN, Kasudhan KS, Naveen M, Batra GK, Chakrabarti S, Avasthi A, Grover S. Precise pharmacogenetic pharmacometabolomic (PPP) guided clozapine therapy in treatment resistant schizophrenia: Insights from one ethnicity experiment. Schizophr Res 2021; 237:26-28. [PMID: 34481201 DOI: 10.1016/j.schres.2021.08.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 08/22/2021] [Accepted: 08/22/2021] [Indexed: 02/05/2023]
Affiliation(s)
- Amol N Patil
- Department of Clinical Pharmacology, PGIMER, Chandigarh, India
| | | | - M Naveen
- Department of Clinical Pharmacology, PGIMER, Chandigarh, India
| | | | | | - Ajit Avasthi
- Department of Psychiatry, PGIMER, Chandigarh, India
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Su Y, Yu H, Wang Z, Liu S, Zhao L, Fu Y, Yang Y, Du B, Zhang F, Zhang X, Huang M, Hou C, Huang G, Su Z, Peng M, Yan R, Zhang Y, Yan H, Wang L, Lu T, Jia F, Li K, Lv L, Wang H, Yu S, Wang Q, Tan Y, Xu Y, Zhang D, Yue W. Protocol for a pharmacogenomic study on individualised antipsychotic drug treatment for patients with schizophrenia. BJPsych Open 2021; 7:e121. [PMID: 34183088 PMCID: PMC8269926 DOI: 10.1192/bjo.2021.945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Schizophrenia is a severe and complex psychiatric disorder that needs treatment based on extensive experience. Antipsychotic drugs have already become the cornerstone of the treatment for schizophrenia; however, the therapeutic effect is of significant variability among patients, and only around a third of patients with schizophrenia show good efficacy. Meanwhile, drug-induced metabolic syndrome and other side-effects significantly affect treatment adherence and prognosis. Therefore, strategies for drug selection are desperately needed. In this study, we will perform pharmacogenomics research and set up an individualised preferred treatment prediction model. AIMS We aim to create a standard clinical cohort, with multidimensional index assessment of antipsychotic treatment for patients with schizophrenia. METHOD This trial is designed as a randomised clinical trial comparing treatment with different kinds of antipsychotics. A total sample of 2000 patients with schizophrenia will be recruited from in-patient units from five clinical research centres. Using a computer-generated program, the participants will be randomly assigned to four treatment groups: aripiprazole, olanzapine, quetiapine and risperidone. The primary outcomes will be measured as changes in the Positive and Negative Syndrome Scale of schizophrenia, which reflects the efficacy. Secondary outcomes include the measure of side-effects, such as metabolic syndromes. The efficacy evaluation and side-effects assessment will be performed at baseline, 2 weeks, 6 weeks and 3 months. RESULTS This trial will assess the efficacy and side effects of antipsychotics and create a standard clinical cohort with a multi-dimensional index assessment of antipsychotic treatment for schizophrenia patients. CONCLUSION This study aims to set up an individualized preferred treatment prediction model through the genetic analysis of patients using different kinds of antipsychotics.
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Affiliation(s)
- Yi Su
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
| | - Hao Yu
- Institute of Mental Health, The Sixth Hospital of Peking University, China; Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China; and Department of Psychiatry, Jining Medical University, China
| | - Zhiren Wang
- Psychiatry Research Center, Beijing HuiLongGuan Hospital, Peking University, China
| | - Sha Liu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, China
| | - Liansheng Zhao
- Mental Health Center, West China Hospital, Sichuan University, China
| | - Yingmei Fu
- Shanghai Mental Health Center, Shanghai Jiaotong University, China
| | - Yongfeng Yang
- Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, China
| | - Bo Du
- Hebei Mental Health Center, The Sixth People's Hospital of Hebei Province, China
| | - Fuquan Zhang
- Wuxi Mental Health Center, Nanjing Medical University, China
| | - Xiangrong Zhang
- Department of Geriatric Psychiatry, Nanjing Brain Hospital Affiliated to Nanjing Medical University, China
| | - Manli Huang
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, China; and The Key Laboratory of Mental Disorder's Management of Zhejiang Province, China
| | - Cailan Hou
- Guangdong Mental Health Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong province, China; and School of Medicine, South China University of Technology, Guangzhou, Guangdong province, China
| | - Guoping Huang
- Department of Psychiatry, Mental Health Center of Sichuan Province, China
| | - Zhonghua Su
- Department of Psychiatry, Jining Mental Hospital, China
| | - Mao Peng
- Department of Neurology, Xuanwu Hospital, Capital Medical University, China
| | - Ran Yan
- Department of Radiology, China-Japan Friendship Hospital Affiliated to the Ministry of Health of PRC, China
| | - Yuyanan Zhang
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
| | - Hao Yan
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
| | - Lifang Wang
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
| | - Tianlan Lu
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
| | - Fujun Jia
- Guangdong Mental Health Center, Guangdong General Hospital, China; and School of Medicine, South China University of Technology, Guangzhou, Guangdong province, China
| | - Keqing Li
- Hebei Mental Health Center, The Sixth People's Hospital of Hebei Province, China
| | - Luxian Lv
- Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, China
| | - Hongxing Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, China
| | - Shunying Yu
- Shanghai Mental Health Center, Shanghai Jiaotong University, China
| | - Qiang Wang
- Mental Health Center, West China Hospital, Sichuan University, China
| | - Yunlong Tan
- HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Peking University, China
| | - Yong Xu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, China
| | - Dai Zhang
- Institute of Mental Health, The Sixth Hospital of Peking University, China; Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China; and Peking-Tsinghua Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Peking University, China
| | - Weihua Yue
- Institute of Mental Health, The Sixth Hospital of Peking University, China; and Key Laboratory of Mental Health, Ministry of Health & National Clinical Research Center for Mental Disorders (Peking University), China
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European Whites May Need Lower Minimum Therapeutic Clozapine Doses Than Those Customarily Proposed. J Clin Psychopharmacol 2021; 41:140-147. [PMID: 33587398 DOI: 10.1097/jcp.0000000000001341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE/BACKGROUND A nomogram from a British naturalistic study proposed that the clozapine dosing needed to reach a serum concentration of 350 ng/mL ranged from 265 mg/d (female nonsmokers) to 525 mg/d (male smokers). Some European reviews have used these dosing recommendations, which seem greater than what we found in an Italian White sample ranging from 245 mg/d (female nonsmokers) to 299 mg/d (male smokers). Five other published samples of European Whites were added to the Italian sample to estimate clozapine doses recommended for reaching 350 ng/mL. METHODS/PROCEDURES Average clozapine metabolizers were obtained by eliminating outliers with confounding variables: (1) psychiatric inducers and inhibitors; (2) doses less than 100 mg/d; and (3) when possible, patients with inflammation, obesity, or using oral contraceptives. The study included 1363 average metabolizer European Whites: the Italian sample and 5 new samples. Mean averages that reached serum concentration levels of 350 ng/mL were calculated after stratification by sex and smoking status in each sample. Then, weighted mean averages were obtained by combining the 6 samples. FINDINGS/RESULTS The estimated weighted mean clozapine dosages ranged from 236 to 368 mg/d (236 mg/d in 218 female nonsmokers, 256 mg/d in 340 male nonsmokers, 357 mg/d in 269 female smokers, and 368 mg/d in 546 male smokers). IMPLICATIONS/CONCLUSIONS Our recommended dosages are less than those recommended in Europe. Future studies in European Whites need to replicate these recommended doses for average metabolizer patients after sex and smoking stratification and further explore clozapine dosing for those with relevant clinical confounders.
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Whiskey E, Romano G, Elliott M, Campbell M, Anandarajah C, Taylor D, Valsraj K. Possible pharmacogenetic factors in clozapine treatment failure: a case report. Ther Adv Psychopharmacol 2021; 11:20451253211030844. [PMID: 35211290 PMCID: PMC8862186 DOI: 10.1177/20451253211030844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/18/2021] [Indexed: 01/19/2023] Open
Abstract
There is still much to learn about the predictors of therapeutic response in psychiatry, but progress is gradually being made and precision psychiatry is an exciting and emerging subspeciality in this field. This is critically important in the treatment of refractory psychotic disorders, where clozapine is the only evidence-based treatment but only about half the patients experience an adequate response. In this case report, we explore the possible biological mechanisms underlying treatment failure and discuss possible ways of improving clinical outcomes. Further work is required to fully understand why some patients fail to respond to the most effective treatment in refractory schizophrenia. Therapeutic drug monitoring together with early pharmacogenetic testing may offer a path for some patients with refractory psychotic symptoms unresponsive to clozapine treatment.
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Affiliation(s)
- Eromona Whiskey
- Pharmacy Department, South London and Maudsley NHS Foundation Trust, Denmark Hill, London, SE5 8AZ, UK
| | | | | | | | | | - David Taylor
- Pharmacy Department, South London and Maudsley NHS Foundation Trust, London, UK
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Li Z, Lee SH, Jeong HJ, Kang HE. Pharmacokinetic changes of clozapine and norclozapine in a rat model of non-alcoholic fatty liver disease induced by orotic acid. Xenobiotica 2020; 51:324-334. [PMID: 33185134 DOI: 10.1080/00498254.2020.1851070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Impaired in vitro oxidation of clozapine has been reported in steatotic rat liver due to downregulation of cytochrome P450 (CYP) 1A. Pharmacokinetic changes of clozapine and its major metabolite, norclozapine, were evaluated in a rat model of non-alcoholic fatty liver disease (NAFLD) induced by orotic acid. Significantly slower in vitro CLint for formation of norclozapine from clozapine was observed in NAFLD rats than in control rats as a result of the reduced protein expression and metabolic activity of CYP1A1/2. However, systemic exposures to clozapine in NAFLD rats were comparable to those in controls after intravenous (4 mg/kg) and oral (10 mg/kg) administration of clozapine. Of note, the AUC of the norclozapine and AUCnorclozapine/AUCclozapine ratio following intravenous and oral administration of clozapine rather increased significantly in NAFLD rats, as a result of the slowed subsequent metabolism of norclozapine via CYP1A1/2. Steady-state brain concentrations of both clozapine and norclozapine were significantly higher in NAFLD rats than those in control rats following intravenous infusion of clozapine. Increased systemic exposure to norclozapine and elevated brain concentrations of clozapine and norclozapine observed in NAFLD rats imply that further studies are warranted on the pharmacotherapy of clozapine in patients with pre-existing or drug-induced hepatic steatosis.
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Affiliation(s)
- Zhengri Li
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, South Korea
| | - Song Hee Lee
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, South Korea
| | - Hee Jin Jeong
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, South Korea
| | - Hee Eun Kang
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, South Korea
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Ivashchenko DV, Khoang SZ, Tazagulova MK, Makhmudova BV, Buromskaya NI, Shimanov PV, Deitch RV, Dorina IV, Nastovich MI, Akmalova KA, Kachanova AA, Grishina EA, Savchenko LM, Shevchenko YS, Sychev DA. The polymorphic variants DRD2 rs1800497 and ABCB1 3435C>T are associated with antipsychotic safety parameters in adolescents with an acute psychotic episode: the results of a pilot study. ACTA ACUST UNITED AC 2020. [DOI: 10.14412/2074-2711-2020-5-24-31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Children and adolescents are more likely than adults to experience adverse side effects when taking antipsychotics. Pharmacogenetic testing allows one to more accurately choose the initial dose of a drug. The genes of pharmacokinetic factors have been shown to be of high prognostic value for the safety of antipsychotics in adults.Patients and methods. The study enrolled 36 adolescents (58.3% male) (mean age, 14.83±1.84 years). All the patients took an antipsychotic. The follow-up lasted 28 days. On 14 and 28 days of treatment, its efficiency and safety were evaluated using the Children's Global Assessment Scale (CGAS), the Positive and Negative Syndrome Scale (PANSS), the Udvalg for Kliniske Undersњgelser Side Effects Rating Scale (UKU-SERS), the Simpson-Angus Scale (SAS), and the Barnes Akathisia Rating Scale (BARS). The patients were genotyped for CYP3A4*22, CYP3A5*3, CYP2D6*4, *9, *10, ABCB1 1236C>T, 2677G>T/A, 3435C>T, DRD2 rs1800497, DRD4 rs1800955, and HTR2A rs6313.Results and discussion. The decrease in the mean score of the PANSS subscale “Productive symptoms” was more pronounced in carriers of the DRD2 rs1800497 polymorphic variant (-6.5 [-10.25; -3.75] vs -3 [-6.5; -2 ] on 14 day (p=0.028) and (-11 [-13; -9.5] vs -5 [-9; -3.5] on 28 day (p=0.001) compared to baseline. The carriage of ABCB1 3435CT+TT was associated with worse tolerance to pharmacotherapy on 14 day (the total score of the UKU-SERS M, 8 [3; 11.75] vs M, 2 [1; 6]; p=0.034). The carriers of DRD2 rs1800497 reported a greater severity of antipsychotic-induced neurological disorders (UKU-SERS subscale score M, 1 [0; 2.25] vs M 0 [0; 1]; p=0.029).Conclusion. The polymorphic variants DRD2 rs1800497 and ABCB1 3435C>T were established to be significantly associated with the efficacy and safety of antipsychotics in adolescents with an acute psychotic episode.
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Affiliation(s)
- D. V. Ivashchenko
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - S. Z. Khoang
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Ministry of Health of Russia
| | - M. Kh. Tazagulova
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | | | - N. I. Buromskaya
- G.E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents, Moscow Healthcare Department
| | - P. V. Shimanov
- G.E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents, Moscow Healthcare Department
| | - R. V. Deitch
- G.E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents, Moscow Healthcare Department
| | - I. V. Dorina
- G.E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents, Moscow Healthcare Department
| | - M. I. Nastovich
- G.E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents, Moscow Healthcare Department
| | - K. A. Akmalova
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - A. A. Kachanova
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - E. A. Grishina
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - L. M. Savchenko
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - Yu. S. Shevchenko
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
| | - D. A. Sychev
- Russian Medical Academy of Continuing Professional Education, Ministry of Health of Russia
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14
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Jovanović M, Vučićević K, Miljković B. Understanding variability in the pharmacokinetics of atypical antipsychotics - focus on clozapine, olanzapine and aripiprazole population models. Drug Metab Rev 2020; 52:1-18. [PMID: 32008418 DOI: 10.1080/03602532.2020.1717517] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Antipsychotic medicines are widely used for the management of psychotic symptoms regardless of the underlying diagnosis. Most atypical antipsychotics undergo extensive metabolism prior to excretion. Various factors may influence their pharmacokinetics, particularly elimination, leading to highly variable drug concentrations between individual patients following the same dosing regimen. Population pharmacokinetic approach, based on nonlinear mixed effects modeling, is a useful tool to identify covariates explaining pharmacokinetic variability, as well as to characterize and distinguish unexplained residual and between-subject (interindividual) variability. In addition, this approach allows the use of both sparsely and intensively sampled data. In this paper, we reviewed the pharmacokinetic characteristics of clozapine, olanzapine and aripiprazole, focusing on a population modeling approach. In particular, models based on a nonlinear mixed effects approach performed by NONMEM® software in order to identify and quantify sources of pharmacokinetic variability are presented. Population models were identified through systematic searches of PubMed and sixteen studies were selected. Some of the factors identified that significantly contribute to variability in elimination among clozapine, olanzapine, and aripiprazole are demographic characteristics, body weight, genetic polymorphism, smoking and in some cases drug interactions. Scientific research based on pharmacometric modeling is useful to further characterize sources of variability and their combined effect.
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Affiliation(s)
- Marija Jovanović
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Katarina Vučićević
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Branislava Miljković
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
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15
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M N, Patil AN, Pattanaik S, Kaur A, Banerjee D, Grover S. ABCB1 and DRD3 polymorphism as a response predicting biomarker and tool for pharmacogenetically guided clozapine dosing in Asian Indian treatment resistant schizophrenia patients. Asian J Psychiatr 2020; 48:101918. [PMID: 31896438 DOI: 10.1016/j.ajp.2019.101918] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/25/2019] [Accepted: 12/25/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate association of two single nucleotide polymorphisms (SNPs) ABCB1(rs1045462) and DRD3(rs6280) with clozapine response and the dose in treatment resistant schizophrenia (TRS) patients. METHODS 200 TRS patients were enrolled in the study during their follow up visit post clozapine initiation. SNP assessment was performed for DRD3 (rs6280) and ABCB1(rs1045462) by sequencing. Blood sample for genotyping was collected with disease and treatment related variables recording on case record form. Patients were classified as responders or nonresponders based upon Andreasen criteria and Positive and Negative Syndrome Scale (PANSS). RESULTS Mean clozapine dose, the genotype frequency distribution of ABCB1, DRD3 SNPs were significantly different in clozapine responder and non-responder study population (p < 0.05). CT genotype of ABCB1 and AG genotype of DRD3 were observed to be more prevalent in the responder group. TT genotype of ABCB1 and AG genotype of DRD3 were prevalent in the nonresponder group. Clozapine dosing equations for responder and nonresponder TRS populations were developed through logistic regression analysis. 27% variability in clozapine dose was explained by possible combinations of ABCB1 and DRD3 SNP analysis. CONCLUSION Differential ABCB1(rs1045462) and DRD3(rs6280) genotype frequencies among the clozapine responders and non-responders explained clear feasibility of response predictor potential along with clozapine dose variability association. Pharmacogenetically guided clozapine dosing is possible if more SNPs are considered together with ABCB1(rs1045462) and DRD3(rs6280) in TRS patients.
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Affiliation(s)
- Naveen M
- Department of Pharmacology, PGIMER, Chandigarh, India
| | - Amol N Patil
- Department of Pharmacology, PGIMER, Chandigarh, India
| | | | - Anit Kaur
- Department of Pediatrics, PGIMER, Chandigarh, India
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16
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Albitar O, Harun SN, Zainal H, Ibrahim B, Sheikh Ghadzi SM. Population Pharmacokinetics of Clozapine: A Systematic Review. BIOMED RESEARCH INTERNATIONAL 2020; 2020:9872936. [PMID: 31998804 PMCID: PMC6970501 DOI: 10.1155/2020/9872936] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND OBJECTIVE Clozapine is a second-generation antipsychotic drug that is considered the most effective treatment for refractory schizophrenia. Several clozapine population pharmacokinetic models have been introduced in the last decades. Thus, a systematic review was performed (i) to compare published pharmacokinetics models and (ii) to summarize and explore identified covariates influencing the clozapine pharmacokinetics models. METHODS A search of publications for population pharmacokinetic analyses of clozapine either in healthy volunteers or patients from inception to April 2019 was conducted in PubMed and SCOPUS databases. Reviews, methodology articles, in vitro and animal studies, and noncompartmental analysis were excluded. RESULTS Twelve studies were included in this review. Clozapine pharmacokinetics was described as one-compartment with first-order absorption and elimination in most of the studies. Significant interindividual variations of clozapine pharmacokinetic parameters were found in most of the included studies. Age, sex, smoking status, and cytochrome P450 1A2 were found to be the most common identified covariates affecting these parameters. External validation was only performed in one study to determine the predictive performance of the models. CONCLUSIONS Large pharmacokinetic variability remains despite the inclusion of several covariates. This can be improved by including other potential factors such as genetic polymorphisms, metabolic factors, and significant drug-drug interactions in a well-designed population pharmacokinetic model in the future, taking into account the incorporation of larger sample size and more stringent sampling strategy. External validation should also be performed to the previously published models to compare their predictive performances.
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Affiliation(s)
- Orwa Albitar
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Sabariah Noor Harun
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Hadzliana Zainal
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Baharudin Ibrahim
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
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17
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Schoretsanitis G, Kane JM, Ruan CJ, Spina E, Hiemke C, de Leon J. A comprehensive review of the clinical utility of and a combined analysis of the clozapine/norclozapine ratio in therapeutic drug monitoring for adult patients. Expert Rev Clin Pharmacol 2019; 12:603-621. [DOI: 10.1080/17512433.2019.1617695] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Georgios Schoretsanitis
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - John M. Kane
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Can-Jun Ruan
- Laboratory of Clinical Psychopharmacology & The National Clinical Research Centre for Mental Disorders & Beijing Key Lab of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Christoph Hiemke
- Department of Psychiatry and Psychotherapy, University Medical Center of Mainz, Mainz, Germany
| | - Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, KY, USA
- Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain
- Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apostol Hospital, University of the Basque Country, Vitoria, Spain
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18
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Clozapine Metabolism in East Asians and Caucasians: A Pilot Exploration of the Prevalence of Poor Metabolizers and a Systematic Review. J Clin Psychopharmacol 2019; 39:135-144. [PMID: 30811372 DOI: 10.1097/jcp.0000000000001018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE/BACKGROUND In clozapine therapeutic drug monitoring (TDM) studies, Chinese reached the same concentrations using half the dosage Caucasians use. Defining clozapine poor metabolizers (PMs) requires stratification by ethnicity, smoking, and sex. METHODS/PROCEDURES After sex and smoking stratification in 129 Chinese inpatients (mean, 8.8 TDM samples per patient), we explored the association between the total concentration-dose (C/D) ratio and CYP1A2 (*1C, *1F, and *7) and CYP2C19 alleles (*2 and *3). A systematic literature review identified 22 clozapine TDM prior studies (13 in Caucasians and 7 in East Asians). FINDINGS/RESULTS In our Chinese sample, the mean total clozapine C/D ratio (ng/mL per mg/d) was 1.96 for 22 male smokers, 2.07 for 5 female smokers, 2.47 for 36 male nonsmokers, and 2.95 for 66 female nonsmokers. CYP1A2 *1C had no significant effects, and CYP1A2 *1F had small effects. Five clozapine PMs (4%) needed low clozapine doses of 75 to 115 mg/d to get therapeutic concentrations. Using the same methodology in a published Italian sample, we found 5 PMs (3.3% of 152). In the systematic review, the clozapine C/D ratio (ng/mL per mg/d) was higher when comparing: (1) weighted mean values of 1.57 in 876 East Asians versus 1.07 in 1147 Caucasians and (2) ranks of 8 East Asians versus 13 Caucasian samples (P < 0.001). IMPLICATIONS/CONCLUSIONS Future TDM studies need to further explore the frequency of clozapine PMs after sex and smoking stratification in East Asian and Caucasian patients. Compared with Caucasians, East Asians appear to have a clinically relevant decrease in clozapine clearance.
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19
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Legge SE, Walters JT. Genetics of clozapine-associated neutropenia: recent advances, challenges and future perspective. Pharmacogenomics 2019; 20:279-290. [PMID: 30767710 PMCID: PMC6563116 DOI: 10.2217/pgs-2018-0188] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Clozapine is the only effective antipsychotic for treatment-resistant schizophrenia but remains widely under prescribed, at least in part due to its potential to cause agranulocytosis and neutropenia. In this article, we provide an overview of the current understanding of the genetics of clozapine-associated agranulocytosis and neutropenia. We now know that the genetic etiology of clozapine-associated neutropenia is complex and is likely to involve variants from several genes including HLA-DQB1, HLA-B and SLCO1B3/SLCO1B7. We describe recent findings relating to the Duffy-null genotype and its association with benign neutropenia in individuals with African ancestry. Further advances will come from sequencing studies, large, cross-population studies and in understanding the molecular mechanisms underlying these associations.
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Affiliation(s)
- Sophie E Legge
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
| | - James Tr Walters
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
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20
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Genetic Polymorphisms Associated With Constipation and Anticholinergic Symptoms in Patients Receiving Clozapine. J Clin Psychopharmacol 2018; 38:193-199. [PMID: 29620694 DOI: 10.1097/jcp.0000000000000885] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Clozapine impairs gastrointestinal motility owing to its anticholinergic and antiserotonergic properties. This commonly leads to constipation and potentially to more severe complications such as bowel obstruction and ischemia. The aim of this study was to determine whether genetic variations in the genes encoding muscarinic and serotonergic receptors (CHRM2, CHRM3, HTR2, HTR3, HTR4, and HTR7) explain the variations in incidence of constipation and anticholinergic symptoms during clozapine treatment. Genes associated with opiate-induced constipation were also included in this analysis (TPH1, OPRM1, ABCB1, and COMT). PROCEDURES Blood samples from 176 clozapine-treated, Finnish, white patients with schizophrenia were genotyped. Constipation and anticholinergic symptoms were rated using the Liverpool University Neuroleptic Side Effect Rating Scale self-report questionnaire. In total, 192 single-nucleotide polymorphisms (SNPs) were detected and grouped to formulate a weighted genetic-risk score (GRS). RESULTS No significant associations between individual SNPs or GRSs and constipation or laxative use were observed. A GRS of 19 SNPs in CHRM2, CHRM3, HTR3C, HTR7, ABCB1, OPRM1, and TPH1 was associated with anticholinergic symptoms in a generalized linear univariate model, with body mass index, clozapine monotherapy, and GRS as explaining variables (permuted P = 0.014). Generalized linear univariate model analysis performed on the opiate-induced constipation-associated SNPs and a single CHRM3 SNP revealed an association between anticholinergic symptoms and a score of 8 SNPs (adjusted P = 0.038, permuted P = 0.002). CONCLUSIONS Two GRSs are able to predict the risk of anticholinergic symptoms in patients receiving clozapine and possibly an increased risk of gastrointestinal hypomotility.
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21
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Papazisis G, Goulas A, Sarrigiannidis A, Bargiota S, Antoniadis D, Raikos N, Basgiouraki E, Bozikas VP, Garyfallos G. ABCB1 and CYP2D6 polymorphisms and treatment response of psychotic patients in a naturalistic setting. Hum Psychopharmacol 2018; 33. [PMID: 29250824 DOI: 10.1002/hup.2644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 08/28/2017] [Accepted: 11/10/2017] [Indexed: 12/25/2022]
Abstract
OBJECTIVES The aim of our study was to examine the association between ABCB1 polymorphisms G2677T/A (rs2032582) and C3435T (rs1045642) and common CYP2D6 variants, with the response to antipsychotic treatment of psychotic patients, in a naturalistic setting, in Greece. METHODS One hundred patients suffering from schizophrenia and other psychotic disorders were included in the study. Dosages were normalized to chlorpromazine equivalents. Response following 1 month of treatment was assessed as either a continuous variable, using the distribution of the corrected Positive and Negative Syndrome Scale percent change, or as a dichotomous variable defined as the number of patients scoring ≥30% from the corrected baseline Positive and Negative Syndrome Scale score. Genotyping was achieved with established polymerase chain reaction-restriction fragment length polymorphism methods. RESULTS With response treated as a continuous variable, the homozygous recessive rs2032582 genotypes (TT) who were simultaneously carriers of a loss-of-function CYP2D6 allele (*4 or *5) responded significantly worse than the rest of the patients. Comparison of genotype frequencies revealed a statistically significant association of the above combination. No significant association between chlorpromazine equivalents and the tested genotypes was detected. CONCLUSION We have detected a possible interaction between ABCB1 and CYP2D6 in affecting response of psychotic patients to drug treatment, in a naturalistic setting.
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Affiliation(s)
- Georgios Papazisis
- Department of Clinical Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Antonios Goulas
- 1st Department of Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexios Sarrigiannidis
- 2nd University Department of Psychiatry, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Stavroula Bargiota
- 2nd University Department of Psychiatry, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Diomidis Antoniadis
- 2nd University Department of Psychiatry, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikolaos Raikos
- Department of Forensic Medicine and Toxicology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Emmanouela Basgiouraki
- 1st Department of Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Vasileios P Bozikas
- 1st University Department of Psychiatry, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Georgios Garyfallos
- 2nd University Department of Psychiatry, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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22
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Smith RM. Advancing psychiatric pharmacogenomics using drug development paradigms. Pharmacogenomics 2017; 18:1459-1467. [PMID: 28975860 DOI: 10.2217/pgs-2017-0104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Drugs used to treat psychiatric disorders, even when taken as directed, fail to provide adequate relief for a sizeable proportion of patients. Despite our advancements in understanding human genetics and development of high-throughput tools to probe variation, pharmacogenomics has yielded marginal ability to predict drug response for psychiatric disorders. Here, I review the current pharmacogenomics paradigm, identifying opportunities to incorporate drug development strategies designed to increase the probability of delivering a successful molecule to the clinic. This includes using in-depth pharmacokinetic profiles, clear measures of target engagement and target-specific pharmacodynamic responses orthogonal to clinical response. The complex pharmacological profiles psychiatric drugs require re-examination of simplified clinical response-oriented pharmacogenetic hypotheses, in favor of a more complete patient profile.
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Affiliation(s)
- Ryan M Smith
- Division of Pharmaceutics & Translational Therapeutics, Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa, College of Pharmacy, 115 South Grand Avenue, S427 Pharmacy Building, Iowa City, IA 52242, USA
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23
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Piatkov I, Caetano D, Assur Y, Lau SL, Jones T, Boyages SC, McLean M. ABCB1 and ABCC1 single-nucleotide polymorphisms in patients treated with clozapine. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2017; 10:235-242. [PMID: 28919802 PMCID: PMC5587196 DOI: 10.2147/pgpm.s142314] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Clozapine (CZ) has superior efficacy to other antipsychotic agents in the treatment of schizophrenia and has been extensively used in clinical practice. ATP-binding cassette (ABC) transporter proteins are responsible for the distribution of various molecules as well as drugs across extracellular and intracellular membranes, including the blood-brain barrier. Genetic variations in these proteins can account for differences in treatment response. We investigated the influence of ABCB1 rs1045642 and ABCC1 rs212090 single-nucleotide polymorphisms (SNPs) on CZ serum level, clinical outcome, and changes in body mass index (BMI) in the first year of CZ treatment. These polymorphisms influenced baseline BMI in males (p=0.009 and 0.054, B1 and C1, respectively), changes in BMI in males after 3 (p=0.026, ABCB1) and 12 months (p=0.022, ABCC1) of CZ treatment, and level of diastolic pressure (p=0.002 and 0.051, respectively). The combination of ABCB1 + ABCC1 homozygote SNPs was associated with increased CZ and norclozapine serum levels (p=0.054 and 0.010, respectively). ABC transporter SNPs could be potential biomarkers for CZ-induced weight gain and cardiovascular complications. Further pharmacogenetic research is warranted to help clinicians with their treatment decision, including concomitant use of drugs and prevention of side effects.
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Affiliation(s)
- Irina Piatkov
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Dorgival Caetano
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Yolinda Assur
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Sue Lynn Lau
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Trudi Jones
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Steven C Boyages
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
| | - Mark McLean
- University Clinic and Research Centre Blacktown, Western Sydney University, Western Sydney Local Health District, Blacktown, NSW, Australia
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Swathy B, Saradalekshmi KR, Nair IV, Nair C, Banerjee M. Pharmacoepigenomic responses of antipsychotic drugs on pharmacogenes are likely to be modulated by miRNAs. Epigenomics 2017; 9:811-821. [DOI: 10.2217/epi-2016-0181] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aim: It is imperative to differentiate the role of host epigenetics from pharmacoepigenetics in resolving therapeutic response. Therefore, the objective was to identify how antipsychotic drugs influence epigenetic response on pharmacogenes. Materials & methods: The study design was based on in vitro evaluation of pharmacoepigenetic response of haloperidol, clozapine and olanzapine. Post antipsychotic treatment, the alterations in expression of ABCB1, CYP1A2 and CYP3A4 were monitored, and followed up by promoter methylation and their target miRNA expression studies. Critical observations were followed up in a restrictive clinical setting. Results: Under in vitro conditions increased expression of ABCB1, CYP1A2 and CYP3A4 was observed which seems to be regulated by miR-27a and miR-128a and not by methylation. A similar pattern was observed in clinical setting with ABCB1, which was reflective of good therapeutic response. Conclusion: The study demonstrates that antipsychotic drugs can influence miRNA-mediated epigenetic response in pharmacogenes resulting in modulating therapeutic response.
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Affiliation(s)
- Babu Swathy
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Koramannil R Saradalekshmi
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Indu V Nair
- Mental Health Centre, Thiruvananthapuram, Kerala, India
| | | | - Moinak Banerjee
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
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25
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Akamine Y, Sugawara-Kikuchi Y, Uno T, Shimizu T, Miura M. Quantification of the steady-state plasma concentrations of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia using a novel HPLC method and the effects of CYPs and ABC transporters polymorphisms. Ann Clin Biochem 2017; 54:677-685. [PMID: 27932669 DOI: 10.1177/0004563216686377] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background This study developed a novel high-performance liquid chromatography (HPLC) method for the simultaneous quantification of clozapine and its active metabolite, N-desmethylclozapine, in human plasma and investigated the effects of various factors, including genetic polymorphisms in cytochrome P450 (CYP) 2D6, CYP3A5, ABCB1 and ABCG2, on the steady-state plasma trough concentrations (C0) of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia. Methods Forty-five patients had been receiving fixed doses of clozapine for at least four weeks. The CYP2D6 ( CYP2D6*2, CYP2D6*5, CYP2D6*10), CYP3A5 ( CYP3A5*3), ABCB1 (1236C > T, 2677G > T/A, 3435C > T) and ABCG2 (421 C > A) genotypes were identified by polymerase chain reaction. Results The within- and between-day coefficients of variation (CV) were less than 11.0%, and accuracy was within 9.0% over the linear range from 10 to 2500 ng/mL for both analytes, and their LOQs were each 10 ng/mL. The median C0/dose (C0/D) ratios of clozapine were significantly higher in patients with the ABCG2 421 A allele than in those with the 421 C/C genotype ( P = 0.010). However, there were no significant differences in C0/D ratios of clozapine and N-desmethylclozapine among ABCB1, CYP2D6 or CYP3A5 genotypes. In multiple regression analysis, including polymorphisms, age, body weight and biochemical data of patients, the ABCG2 polymorphism alone was correlated with the C0/D ratios of clozapine ( R2 = 0.139, P = 0.016). Conclusions Among the various CYPs and drug transporters, BCRP appeared to most strongly influence clozapine exposure. Knowledge of the patient's ABCG2 421 C > A genotype before initiating therapy may be useful when making dosing decisions aimed at achieving optimal clozapine exposure.
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Affiliation(s)
- Yumiko Akamine
- 1 Department of Pharmacy, Akita University Hospital, Akita, Japan
| | - Yuka Sugawara-Kikuchi
- 2 Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Tsukasa Uno
- 3 Department of Pharmacy, Zikeikai-Aoimori Hospital, Aomori, Japan
| | - Tetsuo Shimizu
- 2 Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Masatomo Miura
- 1 Department of Pharmacy, Akita University Hospital, Akita, Japan
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26
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Vasudev K, Choi YH, Norman R, Kim RB, Schwarz UI. Genetic Determinants of Clozapine-Induced Metabolic Side Effects. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2017; 62:138-149. [PMID: 27681143 PMCID: PMC5298525 DOI: 10.1177/0706743716670128] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Atypical antipychotics are linked to a higher incidence of metabolic side effects, including weight gain, dyslipidemia, and diabetes. In this study, we examined the prevalence and potential genetic predictors of metabolic side effects in 60 adult patients on clozapine. METHOD Genetic variants of relevance to clozapine metabolism, clearance, and response were assessed through targeted genotyping of cytochrome P450 enzymes CYP1A2 and CYP2C19, the efflux transporter ABCB1, the serotonin receptor (HTR2C), leptin (LEP), and leptin receptor (LEPR). Clozapine levels and other potential confounders, including concurrent medications, were also included in the analysis. RESULTS More than half of the patients were obese (51%), had metabolic syndrome (52.5%), and 30.5% were overweight. There was a high prevalence of antipsychotic polypharmacy (61.9%). With multivariable linear regression analysis, LEP -2548G>A, LEPR c.668A>G, and HTR2C c.551-3008 C>G were identified as genetic predictors of body mass index (BMI) after considering effects of clozapine dose, blood level, and concurrent medications (adjusted R2 = 0.305). Metabolic syndrome was found to be significantly associated with clozapine level and CYP2C19*2 and LEPR c.668 G alleles. Clozapine levels in patients with metabolic syndrome were significantly higher compared to those without metabolic syndrome (1886 ± 895 vs. 1283 ± 985 ng/mL, P < 0.01) and were associated with the CYP2C19*2 genotype. No association was found between the genetic variants studied and lipid or glucose levels. CONCLUSION This study confirms a high prevalence of metabolic side effects with clozapine and suggests higher clozapine level and pharmacogenetic markers in CYP2C19, LEP, LEPR, and HTR2C receptors as important predictors of BMI and metabolic syndrome.
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Affiliation(s)
- Kamini Vasudev
- 1 Departments of Psychiatry and Medicine, Western University, London, Ontario
| | - Yun-Hee Choi
- 2 Department of Epidemiology and Biostatistics, Western University, London, Ontario
| | - Ross Norman
- 3 Department of Psychiatry and Epidemiology and Biostatistics, Western University, London, Ontario
| | - Richard B Kim
- 4 Department of Medicine, Physiology & Pharmacology, and Oncology, Western University, London, Ontario
| | - Ute I Schwarz
- 4 Department of Medicine, Physiology & Pharmacology, and Oncology, Western University, London, Ontario
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Balibey H, Basoglu C, Lundgren S, Babaoglu MO, Yasar U, Herken H, Rane A, Bozkurt A, Cetin M. CYP1A2*1F Polymorphism Decreases Clinical Response to Clozapine in Patients with Schizophrenia. ACTA ACUST UNITED AC 2016. [DOI: 10.5455/bcp.20110622071701] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
| | | | - Stefan Lundgren
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Melih O. Babaoglu
- Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara-Turkey
| | - Umit Yasar
- Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara-Turkey
| | - Hasan Herken
- Department of Psychiatry, Pamukkale University, Denizli-Turkey
| | - Anders Rane
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Atilla Bozkurt
- Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara-Turkey
| | - Mesut Cetin
- Department of Psychiatry, GATA, Istanbul-Turkey
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28
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Gene polymorphisms potentially related to the pharmacokinetics of clozapine: a systematic review. Int Clin Psychopharmacol 2016; 31:179-84. [PMID: 25563806 DOI: 10.1097/yic.0000000000000065] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clozapine is currently the ultimate effective therapy for otherwise treatment-refractory schizophrenia. However, the drug is also associated with many adverse effects, some of them potentially fatal. Thus, there is an unmet need to predict clinical response to clozapine. As the pharmacokinetics of clozapine vary considerably between and within individuals, there may be an association between genetic polymorphisms and clozapine plasma concentration and consequently, clinical response. We have reviewed studies that have investigated the association between clozapine metabolic pathways related to genes polymorphisms in relation to plasma clozapine concentration and clinical response. Overall, most of the studies reported negative results. The only gene polymorphism that has been found to be associated with clozapine plasma concentration and response was the ABCB1 gene, which codes for transmembrane transporters expressed in the bowel mucosa, blood-brain barrier, kidney and liver. More prospective longitudinal studies are needed to elucidate the possible role of the ABCB1 polymorphism and transmembrane transporters in clozapine pharmacokinetics and clinical response.
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29
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Relation of the Allelic Variants of Multidrug Resistance Gene to Agranulocytosis Associated With Clozapine. J Clin Psychopharmacol 2016; 36:257-61. [PMID: 27043126 DOI: 10.1097/jcp.0000000000000495] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Clozapine use is associated with leukopenia and more rarely agranulocytosis, which may be lethal. The drug and its metabolites are proposed to interact with the multidrug resistance transporter (ABCB1/MDR1) gene product, P-glycoprotein (P-gp). Among various P-glycoprotein genetic polymorphisms, nucleotide changes in exons 26 (C3435T), 21 (G2677T), and 12 (C1236T) have been implicated for changes in pharmacokinetics and pharmacodynamics of many substrate drugs. In this study, we aimed to investigate the association between these specific ABCB1 polymorphisms and clozapine-associated agranulocytosis (CAA). Ten patients with a history of CAA and 91 control patients without a history of CAA, despite 10 years of continuous clozapine use, were included. Patient recruitment and blood sample collection were conducted at the Hacettepe University Faculty of Medicine, Department of Psychiatry, in collaboration with the members of the Schizophrenia and Other Psychotic Disorders Section of the Psychiatric Association of Turkey, working in various psychiatry clinics. After DNA extraction from peripheral blood lymphocytes, genotyping was performed using polymerase chain reaction and endonuclease digestion. Patients with CAA had shorter duration of clozapine use but did not show any significant difference in other clinical, sociodemographic characteristics and in genotypic or allelic distributions of ABCB1 variants and haplotypes compared with control patients. Among the 10 patients with CAA, none carried the ABCB1 all-variant haplotype (TT-TT-TT), whereas the frequency of this haplotype was approximately 12% among the controls. Larger sample size studies and thorough genetic analyses may reveal both genetic risk and protective factors for this serious adverse event.
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30
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van der Weide K, Loovers H, Pondman K, Bogers J, van der Straaten T, Langemeijer E, Cohen D, Commandeur J, van der Weide J. Genetic risk factors for clozapine-induced neutropenia and agranulocytosis in a Dutch psychiatric population. THE PHARMACOGENOMICS JOURNAL 2016; 17:471-478. [PMID: 27168101 DOI: 10.1038/tpj.2016.32] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/03/2016] [Accepted: 04/15/2016] [Indexed: 12/21/2022]
Abstract
Prescription of clozapine is complicated by the occurrence of clozapine-induced reduction of neutrophils. The aim of this study was to identify genetic risk factors in a population of 310 Dutch patients treated with clozapine, including 38 patients developing neutropenia and 31 patients developing agranulocytosis. NQO2 1541AA (NRH quinone oxidoreductase 2; protects cells against oxidative metabolites) was present at a higher frequency in agranulocytosis patients compared with control (23% versus 7%, P=0.03), as was ABCB1 (ABC-transporter-B1; drug efflux transporter) 3435TT (32% versus 20%, P=0.05). In patients developing neutropenia, ABCB1 3435TT and homozygosity for GSTT1null (glutathione-S-transferase; conjugates reactive clozapine metabolites into glutathione) were more frequent compared with control (34% versus 20%, P=0.05 and 31% versus 14%, P=0.03), whereas GSTM1null was less frequent in these patients (31% versus 52%, P=0.03). To investigate whether combinations of the identified genetic risk factors have a higher predictive value, should be confirmed in a larger case-control study.
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Affiliation(s)
- K van der Weide
- Department of Clinical Chemistry, St Jansdal Hospital, Harderwijk, The Netherlands
| | - H Loovers
- Department of Clinical Chemistry, St Jansdal Hospital, Harderwijk, The Netherlands.,Psychiatric Hospital GGz Centraal, Dependance Meerkanten, Ermelo, The Netherlands
| | - K Pondman
- Department of Clinical Chemistry, St Jansdal Hospital, Harderwijk, The Netherlands
| | - J Bogers
- Mental Health Services Rivierduinen, Oegstgeest, The Netherlands
| | - T van der Straaten
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - E Langemeijer
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - D Cohen
- Mental Health Services North-Holland North, Heerhugowaard, The Netherlands
| | - J Commandeur
- AIMMS-Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU Amsterdam, Amsterdam, The Netherlands
| | - J van der Weide
- Department of Clinical Chemistry, St Jansdal Hospital, Harderwijk, The Netherlands.,Psychiatric Hospital GGz Centraal, Dependance Meerkanten, Ermelo, The Netherlands
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31
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Wolking S, Schaeffeler E, Lerche H, Schwab M, Nies AT. Impact of Genetic Polymorphisms of ABCB1 (MDR1, P-Glycoprotein) on Drug Disposition and Potential Clinical Implications: Update of the Literature. Clin Pharmacokinet 2016; 54:709-35. [PMID: 25860377 DOI: 10.1007/s40262-015-0267-1] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ATP-binding cassette transporter B1 (ABCB1; P-glycoprotein; multidrug resistance protein 1) is an adenosine triphosphate (ATP)-dependent efflux transporter located in the plasma membrane of many different cell types. Numerous structurally unrelated compounds, including drugs and environmental toxins, have been identified as substrates. ABCB1 limits the absorption of xenobiotics from the gut lumen, protects sensitive tissues (e.g. the brain, fetus and testes) from xenobiotics and is involved in biliary and renal secretion of its substrates. In recent years, a large number of polymorphisms of the ABCB1 [ATP-binding cassette, sub-family B (MDR/TAP), member 1] gene have been described. The variants 1236C>T (rs1128503, p.G412G), 2677G>T/A (rs2032582, p.A893S/T) and 3435C>T (rs1045642, p.I1145I) occur at high allele frequencies and create a common haplotype; therefore, they have been most widely studied. This review provides an overview of clinical studies published between 2002 and March 2015. In summary, the effect of ABCB1 variation on P-glycoprotein expression (messenger RNA and protein expression) and/or activity in various tissues (e.g. the liver, gut and heart) appears to be small. Although polymorphisms and haplotypes of ABCB1 have been associated with alterations in drug disposition and drug response, including adverse events with various ABCB1 substrates in different ethnic populations, the results have been majorly conflicting, with limited clinical relevance. Future research activities are warranted, considering a deep-sequencing approach, as well as well-designed clinical studies with appropriate sample sizes to elucidate the impact of rare ABCB1 variants and their potential consequences for effect sizes.
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Affiliation(s)
- Stefan Wolking
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler Strasse 3, 72076, Tübingen, Germany
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32
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Association studies of genomic variants with treatment response to risperidone, clozapine, quetiapine and chlorpromazine in the Chinese Han population. THE PHARMACOGENOMICS JOURNAL 2015; 16:357-65. [PMID: 26282453 DOI: 10.1038/tpj.2015.61] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/08/2015] [Accepted: 07/14/2015] [Indexed: 01/01/2023]
Abstract
Schizophrenia is a widespread mental disease with a prevalence of about 1% in the world population. Continuous long-term treatment is required to maintain social functioning and prevent symptom relapse of schizophrenia patients. However, there are considerable individual differences in response to the antipsychotic drugs. There is a pressing need to identify more drug-response-related markers. But most pharmacogenomics of schizophrenia have typically focused on a few candidate genes in small sample size. In this study, 995 subjects were selected for discovering the drug-response-related markers. A total of 77 single-nucleotide polymorphisms of 25 genes have been investigated for four commonly used antipsychotic drugs in China: risperidone, clozapine, quetiapine, and chlorpromazine. Significant associations with treatment response for several genes, such as CYP2D6, CYP2C19, COMT, ABCB1, DRD3 and HTR2C have been verified in our study. Also, we found several new candidate genes (TNIK, RELN, NOTCH4 and SLC6A2) and combinations (haplotype rs1544325-rs5993883-rs6269-rs4818 in COMT) that are associated with treatment response to the four drugs. Also, multivariate interactions analysis demonstrated the combination of rs6269 in COMT and rs3813929 in HTR2C may work as a predictor to improve the clinical antipsychotic response. So our study is of great significance to improve current knowledge on the pharmacogenomics of schizophrenia, thus promoting the implementation of personalized medicine in schizophrenia.The Pharmacogenomics Journal advance online publication, 18 August 2015; doi:10.1038/tpj.2015.61.
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Abstract
This review considers pharmacogenetics of the so called 'second-generation' antipsychotics. Findings for polymorphisms replicating in more than one study are emphasized and compared and contrasted with larger-scale candidate gene studies and genome-wide association study analyses. Variants in three types of genes are discussed: pharmacokinetic genes associated with drug metabolism and disposition, pharmacodynamic genes encoding drug targets, and pharmacotypic genes impacting disease presentation and subtype. Among pharmacokinetic markers, CYP2D6 metabolizer phenotype has clear clinical significance, as it impacts dosing considerations for aripiprazole, iloperidone and risperidone, and variants of the ABCB1 gene hold promise as biomarkers for dosing for olanzapine and clozapine. Among pharmacodynamic variants, the TaqIA1 allele of the DRD2 gene, the DRD3 (Ser9Gly) polymorphism, and the HTR2C -759C/T polymorphism have emerged as potential biomarkers for response and/or side effects. However, large-scale candidate gene studies and genome-wide association studies indicate that pharmacotypic genes may ultimately prove to be the richest source of biomarkers for response and side effect profiles for second-generation antipsychotics.
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Affiliation(s)
- Mark D Brennan
- Department of Biochemistry & Molecular Biology, School of Medicine, University of Louisville, Louisville, KY 40292, USA.
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34
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Tovilla-Zárate CA, Vargas I, Hernández S, Fresán A, Aguilar A, Escamilla R, Saracco R, Palacios J, Camarena B. Association study between the MDR1 gene and clinical characteristics in schizophrenia. REVISTA BRASILEIRA DE PSIQUIATRIA 2014; 36:227-32. [DOI: 10.1590/1516-4446-2013-1270] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/23/2013] [Indexed: 01/23/2023]
Affiliation(s)
| | - Iván Vargas
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | - Sandra Hernández
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | - Ana Fresán
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | | | - Raúl Escamilla
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | - Ricardo Saracco
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | - Jorge Palacios
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
| | - Beatriz Camarena
- Instituto Nacional de Psiquiatría Ramón de la Fuente Muãiz, Mexico
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Kohlrausch FB. Pharmacogenetics in schizophrenia: a review of clozapine studies. BRAZILIAN JOURNAL OF PSYCHIATRY 2014; 35:305-17. [PMID: 24142094 DOI: 10.1590/1516-4446-2012-0970] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 12/19/2012] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Clozapine is quite effective to treat schizophrenia, but its use is complicated by several factors. Although many patients respond to antipsychotic therapy, about 50% of them exhibit inadequate response, and ineffective medication trials may entail weeks of unremitted illness, potential adverse drug reactions, and treatment nonadherence. This review of the literature sought to describe the main pharmacogenetic studies of clozapine and the genes that potentially influence response to treatment with this medication in schizophrenics. METHODS We searched the PubMed database for studies published in English in the last 20 years using keywords related to the topic. RESULTS AND CONCLUSIONS Our search yielded 145 studies that met the search and selection criteria. Of these, 21 review articles were excluded. The 124 studies included for analysis showed controversial results. Therefore, efforts to identify key gene mechanisms that will be useful in predicting clozapine response and side effects have not been fully successful. Further studies with new analysis approaches and larger sample sizes are still required.
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Xu Q, Wu X, Xiong Y, Xing Q, He L, Qin S. Pharmacogenomics can improve antipsychotic treatment in schizophrenia. Front Med 2013; 7:180-90. [PMID: 23606027 DOI: 10.1007/s11684-013-0249-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 12/21/2012] [Indexed: 01/11/2023]
Abstract
Schizophrenia is a widespread mental disease with a prevalence of about 1% in the world population, and heritability of up to 80%. Drug therapy is an important approach to treating the disease. However, the curative effect of antipsychotic is far from satisfactory in terms of tolerability and side effects. Many studies have indicated that about 30% of the patients exhibit little or no improvements associated with antipsychotics. The response of individual patients who are given the same dose of the same drug varies considerably. In addition, antipsychotic drugs are often accompanied by adverse drug reactions (ADRs), which can cause considerable financial loss in addition to the obvious societal harm. So, it is strongly recommended that personalized medicine should be implemented both to improve drug efficacy and to minimize adverse events and toxicity. There is therefore a need for pharmacogenomic studies into the factors affecting response of schizophrenia patients to antipsychotic drugs to provide informed guidance for clinicians. Individual differences in drug response is due to a combination of many complex factors including ADEM (absorption, distribution, metabolism, excretion) process, transporting, binding with receptor and intracellular signal transduction. Pharmacogenetic and pharmacogenomic studies have successfully identified genetic variants that contribute to this interindividual variability in antipsychotics response. In addition, epigenetic factors such as methylation of DNA and regulation by miRNA have also been reported to play an important role in the complex interactions between the multiple genes and environmental factors which influence individual drug response phenotypes in patients. In this review, we will focus on the latest research on polymorphisms of candidate genes that code for drug metabolic enzymes (CYP2D6, CYP1A2, CYP3A4, etc.), drug transporters (mainly ABCB1) and neurotransmitter receptors (dopamine receptors and serotonin receptors, etc.). We also discuss the genome-wide pharmacogenomic study of schizophrenia and review the current state of knowledge on epigenetics and potential clinical applications.
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Affiliation(s)
- Qingqing Xu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
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Association study of 27 annotated genes for clozapine pharmacogenetics: validation of preexisting studies and identification of a new candidate gene, ABCB1, for treatment response. J Clin Psychopharmacol 2012; 32:441-8. [PMID: 22722500 DOI: 10.1097/jcp.0b013e31825ac35c] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Pharmacogenetic studies on clozapine (CLZ) have provided meaningful insights but have shown redundancies owing to wide interindividual variability and insufficient replication. The present study was designed to validate hitherto suggested candidate genes on CLZ pharmacokinetics and pharmacodynamics and explore new markers through an integrative study. METHODS Based on a literature review, a total of 127 variations in 27 candidate genes were selected and analyzed. Ninety-six schizophrenic patients of Korean ethnicity with constant CLZ dosing were recruited, and information on body weight and smoking habits was gathered, as well as plasma drug levels and treatment responses. RESULTS Among the pharmacokinetic-related single nucleotide polymorphisms, rs2069521 and rs2069522 in CYP1A2 for CLZ/(dose/weight) and norclozapine/(dose/weight) and rs1135840 in CYP2D6 for norclozapine/CLZ showed borderline associations that were insignificant after correction for multiple testing. Regarding treatment response, significant associations were exhibited in rs7787082 and rs10248420 of ABCB1 (P = 0.0005 and P = 0.0013, respectively) even after correction, and the rs7787082 G and rs10248420 A alleles in ABCB1 were more frequently observed in nonresponders. We also observed a trend in the associations of rs13064530 in HRH1 and rs4938013 in DRD2/ANKK1 with treatment response. CONCLUSIONS We could not convincingly replicate most of the previous studies, a result that is possibly due to modest association between the suggested genes. Rather, we found a new candidate gene, ABCB1, for treatment response, which may provide a hypothesis on the relationship between the blood-brain distribution of CLZ and its clinical efficacy.
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Vijayan NN, Mathew A, Balan S, Natarajan C, Nair CM, Allencherry PM, Banerjee M. Antipsychotic drug dosage and therapeutic response in schizophrenia is influenced by ABCB1 genotypes: a study from a south Indian perspective. Pharmacogenomics 2012; 13:1119-27. [DOI: 10.2217/pgs.12.86] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Aim: The conventional practice of using trial and error mode to select antipsychotic drugs in treatment of schizophrenia can result in symptom exacerbations, relapse and severe side effects, resulting in higher costs of treatment. P-glycoprotein (ABCB1) is known to regulate the concentration of antipsychotic drugs in the brain. Variable expressivity based on polymorphism in the gene ABCB1 may reflect on the drug response and its relationship to dosage. Materials & methods: All antipsychotic dosages administered to patients were converted to common chlorpromazine equivalents. Response to antipsychotics was based on 50% cutoff in Brief Psychiatric Rating Scale ratings after 1-year of follow-up. Using a case–control study design, ABCB1 polymorphisms were screened in 192 individuals grouped into responders and nonresponders. Results: A strong allelic, genotypic and haplotypic association, was observed, which was predictive of good response to antipsychotics. Individuals carrying the favorable homozygous genotypes of rs1045642 and rs2032582 displayed better response with increased dosage while those carrying risk genotype manifested refractoriness on increased dosage. Conclusion: The study suggests that a priori knowledge of ABCB1 genotypes can provide a significant input into evaluating the patient’s response to medication, and minimizing redundant dosing and refractoriness. Original submitted 14 February 2012; Revision submitted 14 May 2012
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Affiliation(s)
- Neetha N Vijayan
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Anila Mathew
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Shabeesh Balan
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Chandrasekhar Natarajan
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | | | | | - Moinak Banerjee
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
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Cremers TIFH, Flik G, Hofland C, Stratford RE. Microdialysis evaluation of clozapine and N-desmethylclozapine pharmacokinetics in rat brain. Drug Metab Dispos 2012; 40:1909-16. [PMID: 22736307 DOI: 10.1124/dmd.112.045682] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A significant barrier to realization of the full potential of clozapine as a therapeutic agent in the treatment of schizophrenia is the substantial interpatient variability that exists along the therapeutic continuum of no response-efficacious response-adverse response. Genetic polymorphisms that manifest as highly variable pharmacodynamic and pharmacokinetic measures are its expected causes. To support investigations that seek to understand these causes, the plasma and central nervous system pharmacokinetics of clozapine were determined in rats, the latter using microdialysis sampling. Results obtained with clozapine and N-desmethylclozapine, a pharmacologically active human metabolite that was administered to a separate group of animals, support a conclusion of net carrier-mediated efflux of both compounds across the blood-brain barrier. These results are supported by the replication of published findings regarding the passive transport and net efflux transport of two model compounds, escitalopram and risperidone, respectively. The results obtained with clozapine and N-desmethylclozapine are considered a first step in the development of preclinical pharmacokinetic-pharmacodynamic models that will support deeper mechanistic studies of clozapine in in vivo pharmacology, as well as the development of translational models that augment pharmacogenetic investigations that seek to improve the safety and efficacy of clozapine therapeutic intervention in the treatment of schizophrenia.
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Ieiri I. Functional significance of genetic polymorphisms in P-glycoprotein (MDR1, ABCB1) and breast cancer resistance protein (BCRP, ABCG2). Drug Metab Pharmacokinet 2011; 27:85-105. [PMID: 22123128 DOI: 10.2133/dmpk.dmpk-11-rv-098] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent pharmacogenomic/pharmacogenetic (PGx) studies have disclosed important roles for drug transporters in the human body. Changes in the functions of drug transporters due to drug/food interactions or genetic polymorphisms, for example, are associated with large changes in pharmacokinetic (PK) profiles of substrate drugs, leading to changes in drug response and side effects. This information is extremely useful not only for drug development but also for individualized treatment. Among drug transporters, the ATP-binding cassette (ABC) transporters are expressed in most tissues in humans, and play protective roles; reducing drug absorption from the gastrointestinal tract, enhancing drug elimination into bile and urine, and impeding the entry of drugs into the central nervous system and placenta. In addition to PK/pharmacodynamic (PD) issues, ABC transporters are reported as etiologic and prognostic factors (or biomarkers) for genetic disorders. Although a consensus has not yet been reached, clinical studies have demonstrated that the PGx of ABC transporters influences the overall outcome of pharmacotherapy and contributes to the pathogenesis and progression of certain disorders. This review explains the impact of PGx in ABC transporters in terms of PK/PD, focusing on P-glycoprotein and breast cancer resistance protein (BCRP).
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Affiliation(s)
- Ichiro Ieiri
- Department of Clinical Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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Moons T, de Roo M, Claes S, Dom G. Relationship between P-glycoprotein and second-generation antipsychotics. Pharmacogenomics 2011; 12:1193-211. [PMID: 21843066 DOI: 10.2217/pgs.11.55] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The membrane transport protein P-glycoprotein (P-gp) is an interesting candidate for individual differences in response to antipsychotics. To present an overview of the current knowledge of P-gp and its interaction with second-generation antipsychotics (SGAs), an internet search for all relevant English original research articles concerning P-gp and SGAs was conducted. Several SGAs are substrates for P-gp in therapeutic concentrations. These include amisulpride, aripiprazole, olanzapine, perospirone, risperidone and paliperidone. Clozapine and quetiapine are not likely to be substrates of P-gp. However, most antipsychotics act as inhibitors of P-gp, and can therefore influence plasma and brain concentrations of other substrates. No information was available for sertindole, ziprasidone or zotepine. Research in animal models demonstrated significant differences in antipsychotic brain concentration and behavior owing to both P-gp knockout and inhibition. Results in patients are less clear, as several external factors have to be accounted for. Patients with polymorphisms which decrease P-gp functionality tend to perform better in clinical settings. There is some variability in the findings concerning adverse effects, and no definitive conclusions can be drawn at this point.
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Affiliation(s)
- Tim Moons
- University Psychiatric Centre, Catholic University Leuven, Herestraat 49, 3000 Leuven, Belgium.
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Agranulocytosis related to clozapine in monozygotic twins and association with allelic variants of multidrug resistance gene MDR1. J Clin Psychopharmacol 2011; 31:247-9. [PMID: 21364339 DOI: 10.1097/jcp.0b013e31821084dc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Bersani FS, Capra E, Minichino A, Pannese R, Girardi N, Marini I, Delle Chiaie R, Biondi M. Factors affecting interindividual differences in clozapine response: a review and case report. Hum Psychopharmacol 2011; 26:177-87. [PMID: 21455971 DOI: 10.1002/hup.1191] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Clozapine is the most powerful new‐generation antipsychotic. Although this drug leads to great therapeutic benefits, two types of undesirable conditions frequently occur with its use: side effects and resistance to treatment. Therapeutic drug monitoring of clozapine would be very useful to avoid both these situations. The necessity of monitoring the therapy is the result of a wide interindividual variability in the metabolism of clozapine. In this review, we highlight all the conditions underlying this variability, analyzing them one by one. METHODS Relevant literature was identified through a search of MEDLINE and PubMed. In addition, the case of a treatment‐resistant patient with accelerated metabolism of clozapine is reported as representative of utility of therapeutic drug monitoring in terms of clozapine dose adjustment. RESULTS Genetic polymorphisms of cytochrome P450 enzymes and of neurotransmitter receptors; drug interactions; interactions of clozapine with other substances such as food and drink; smoking; and nonmodifiable variables such as age, ethnicity, and gender have been examined in relation to the existing scientific literature. The laboratory techniques that clinicians could use to identify these variables and adequate therapies are also reviewed.
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Ultra-resistant schizophrenia is not associated with the multidrug-resistant transporter 1 (MDR1) gene rs1045642 variant. J Clin Psychopharmacol 2011; 31:236-8. [PMID: 21364332 DOI: 10.1097/jcp.0b013e31820f9152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.
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Affiliation(s)
- Peter P Zandi
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Hampton House, Room 857, 624 North Broadway, Baltimore, MD 21205, USA.
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Abstract
Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.
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Affiliation(s)
- Peter P Zandi
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Hampton House, Baltimore, MD 21205, USA.
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Sterling JA. Recent Publications on Medications and Pharmacy. Hosp Pharm 2009. [DOI: 10.1310/hpj4410-917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest regarding a broad scope of topics are abstracted monthly.
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