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Silva E, Higgins M, Hammer B, Stephenson P. Clozapine re-challenge and initiation following neutropenia: a review and case series of 14 patients in a high-secure forensic hospital. Ther Adv Psychopharmacol 2021; 11:20451253211015070. [PMID: 34221348 PMCID: PMC8221694 DOI: 10.1177/20451253211015070] [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: 11/13/2020] [Accepted: 04/16/2021] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Clozapine remains the most effective intervention for treatment resistant schizophrenia; however, its use is prohibited following neutropenias. We review neutrophil biology as applied to clozapine and describe the strategies to initiate clozapine following neutropenia used in a case series of 14 consecutive patients rechallenged in a United Kingdom (UK) high-secure psychiatric hospital. We examine outcomes including the use of seclusion and transfer. METHODS A case series of 14 male patients with treatment resistant schizophrenia treated with clozapine despite previous episodes of neutropenia between 2006 and 2015 is presented. Data were collected during 2015 and 2019. Using this routinely collected clinical data, we describe the patient characteristics, causes of neutropenia, the strategies used for rechallenging with clozapine and clinical outcomes. RESULTS Previous neutropenias were the result of benign ethnic neutropenia, clozapine, other medications and autoimmune-related. Our risk mitigation strategies included: granulocyte-colony stimulating factor (G-CSF), lithium and watch-and-wait. There were no serious adverse events; at follow up half of the patient's had improved sufficiently to transfer them to conditions of lesser security. There were dramatic reductions in the use of seclusion. CONCLUSION Even in this extreme group, clozapine can be safely and effectively re/initiated following neutropenias, resulting in marked benefits for patients. This requires careful planning based on an understanding of neutrophil biology and the aetiology of the specific episode of neutropenia.
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Affiliation(s)
- Edward Silva
- Rathbone Low Secure Unit, Mersey Care NHS Foundation Trust, Rathbone Hospital, Mill Lane, Liverpool, L13 4AW, UK
| | - Melanie Higgins
- Ashworth Hospital, Mersey Care NHS Foundation Trust, Liverpool, UK
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Silva E, Higgins M, Hammer B, Stephenson P. Clozapine rechallenge and initiation despite neutropenia- a practical, step-by-step guide. BMC Psychiatry 2020; 20:279. [PMID: 32503471 PMCID: PMC7275543 DOI: 10.1186/s12888-020-02592-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 04/07/2020] [Indexed: 12/16/2022] Open
Abstract
Clozapine remains the only drug treatment likely to benefit patients with treatment resistant schizophrenia. Its use is complicated by an increased risk of neutropenia and so there are stringent monitoring requirements and restrictions in those with previous neutropenia from any cause or from clozapine in particular. Despite these difficulties clozapine may yet be used following neutropenia, albeit with caution. Having had involvement with 14 cases of clozapine use in these circumstances we set out our approach to the assessment of risks and benefits, risk mitigation and monitoring with a practical guide.
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Affiliation(s)
- Edward Silva
- Consultant Forensic Psychiatrist, Ashworth Hospital, Mersey Care NHS Foundation Trust, Parkbourn, Maghull, Merseyside, L31 1HW, UK.
| | - Melanie Higgins
- Consultant Forensic Psychiatrist, Ashworth Hospital, Mersey Care NHS Foundation Trust, Parkbourn, Maghull, Merseyside, L31 1HW, UK
| | - Barbara Hammer
- Consultant Haematologist, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, Wirral, CH49 5PE, UK
| | - Paul Stephenson
- Consultant Forensic Psychiatrist, Ashworth Hospital, Mersey Care NHS Foundation Trust, Parkbourn, Maghull, Merseyside, L31 1HW, UK
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Yoshida K, Müller DJ. Pharmacogenetics of Antipsychotic Drug Treatment: Update and Clinical Implications. MOLECULAR NEUROPSYCHIATRY 2020; 5:1-26. [PMID: 32399466 PMCID: PMC7206586 DOI: 10.1159/000492332] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/20/2018] [Indexed: 12/24/2022]
Abstract
Numerous genetic variants have been shown to be associated with antipsychotic response and adverse effects of schizophrenia treatment. However, the clinical application of these findings is limited. The aim of this narrative review is to summarize the most recent publications and recommendations related to the genetics of antipsychotic treatment and shed light on the clinical utility of pharmacogenetics/pharmacogenomics (PGx). We reviewed the literature on PGx studies with antipsychotic drugs (i.e., antipsychotic response and adverse effects) and commonly used commercial PGx tools for clinical practice. Publications and reviews were included with emphasis on articles published between January 2015 and April 2018. We found 44 studies focusing on antipsychotic response and 45 studies on adverse effects (e.g., antipsychotic-induced weight gain, movement disorders, hormonal abnormality, and clozapine-induced agranulocytosis/granulocytopenia), albeit with mixed results. Overall, several gene variants related to antipsychotic response and adverse effects in the treatment of patients with schizophrenia have been reported, and several commercial pharmacogenomic tests have become available. However, further well-designed investigations and replication studies in large and well-characterized samples are needed to facilitate the application of PGx findings to clinical practice.
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Affiliation(s)
- Kazunari Yoshida
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Daniel J. Müller
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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Eap CB. Personalized prescribing: a new medical model for clinical implementation of psychotropic drugs. DIALOGUES IN CLINICAL NEUROSCIENCE 2017. [PMID: 27757065 PMCID: PMC5067148 DOI: 10.31887/dcns.2016.18.3/ceap] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The use of pharmacogenetic tests was already being proposed in psychiatry in the early 2000s because genetic factors were known to influence drug pharmacokinetics and pharmacodynamics. However, sufficient levels of evidence to justify routine use have been achieved for only a few tests (eg, major histocompatibility complex, class I, B, allele 1502 [HLA-B*1502] for carbamazepine in epilepsy and bipolar disorders); many findings are too preliminary or, when replicated, of low clinical relevance because of a small effect size. Although drug selection and dose adaptation according to cytochrome P450 genotypes are sound, a large number of patients need to be genotyped in order to prevent one case of severe side effect and/or nonresponse. The decrease in cost for genetic analysis shifts the cost: benefit ratio toward increasing use of pharmacogenetic tests. However, they have to be combined with careful clinical evaluations and other tools (eg, therapeutic drug monitoring and phenotyping) to contribute to the general aim of providing the best care for psychiatric patients.
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Affiliation(s)
- Chin B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Centre for Psychiatric Neurosciences, Department of Psychiatry, Lausanne University Hospital, Prilly, Switzerland; School of Pharmacy, Department of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
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Ingimarsson O, MacCabe JH, Haraldsson M, Jónsdóttir H, Sigurdsson E. Neutropenia and agranulocytosis during treatment of schizophrenia with clozapine versus other antipsychotics: an observational study in Iceland. BMC Psychiatry 2016; 16:441. [PMID: 27955666 PMCID: PMC5153901 DOI: 10.1186/s12888-016-1167-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 12/09/2016] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Data on the haematological outcomes of patients who continue clozapine treatment following neutropenia are very rare as even mild neutropenia results in mandatory discontinuation of clozapine in most countries. However, in Iceland where clozapine monitoring is less stringent allows an observational study to be done on the risk of agranulocytosis and neutropenia during treatment with clozapine compared with other antipsychotics among patients with schizophrenia. METHODS The present study is a part of a wider ongoing longitudinal study of schizophrenia in Iceland. We identified 201 patients with schizophrenia treated with clozapine and 410 patients with schizophrenia who had never been on clozapine by searching the electronic health records of Landspitali, the National University Hospital. Neutrophil counts were searched in electronic databases to identify patients who developed neutropenia/agranulocytosis and the frequency of neutrophil measurements was examined as well. RESULTS The median number of days between neutrophil measurements during the first 18 weeks of clozapine treatment was 25 days but after the first 18 weeks on the drug the median became 124 days. Thirty four cases of neutropenia were identified during clozapine treatment with an average follow up time of 9.2 years. The majority, 24 individuals developed mild neutropenia (1500-1900 neutrophils/mm3). None of these progressed to agranulocytosis. The remaining 10 patients developed neutropenia in the range 500-1400 /mm3 of whom one developed agranulocytosis, three stopped clozapine use and 6 patients continued on clozapine for at least a year without developing agranulocytosis. Unexpectedly, schizophrenia patients on other antipsychotics had an equal risk of developing neutropenia as those on clozapine. CONCLUSIONS Neutropenia is common both in patients with schizophrenia on clozapine treatment and in those never on clozapine. Therefore a large part of neutropenia during clozapine treatment is probably not caused by clozapine. These findings have implications in assessing the balance between the risk of progression from neutropenia to agranulocytosis against the morbidity resulting from the premature discontinuation of clozapine under the current monitoring regulations in the US and in most of Europe.
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Affiliation(s)
- Oddur Ingimarsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, Iceland ,Landspitali University Hospital, Mental Health Services, Hringbraut, 101 Reykjavik, Iceland
| | - James H. MacCabe
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College, London, UK ,National Psychosis Unit, Bethlem Royal Hospital, South London and Maudsley NHS Foundation Trust, London, UK
| | - Magnús Haraldsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, Iceland ,Landspitali University Hospital, Mental Health Services, Hringbraut, 101 Reykjavik, Iceland
| | - Halldóra Jónsdóttir
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, Iceland ,Landspitali University Hospital, Mental Health Services, Hringbraut, 101 Reykjavik, Iceland
| | - Engilbert Sigurdsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, Iceland. .,Landspitali University Hospital, Mental Health Services, Hringbraut, 101, Reykjavik, Iceland.
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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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Verbelen M, Lewis CM. How close are we to a pharmacogenomic test for clozapine-induced agranulocytosis? Pharmacogenomics 2015; 16:915-7. [PMID: 26122865 DOI: 10.2217/pgs.15.67] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Moira Verbelen
- MRC SGDP Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, Denmark Hill, London, SE5 8AF, UK
| | - Cathryn M Lewis
- MRC SGDP Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, Denmark Hill, London, SE5 8AF, UK.,Department of Medical & Molecular Genetics, King's College London, 8th Floor Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK
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Verbelen M, Collier DA, Cohen D, MacCabe JH, Lewis CM. Establishing the characteristics of an effective pharmacogenetic test for clozapine-induced agranulocytosis. THE PHARMACOGENOMICS JOURNAL 2015; 15:461-6. [PMID: 25732907 PMCID: PMC4762904 DOI: 10.1038/tpj.2015.5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/18/2014] [Accepted: 12/19/2014] [Indexed: 12/24/2022]
Abstract
Clozapine is the only evidence-based therapy for treatment-resistant schizophrenia, but it induces agranulocytosis, a rare but potentially fatal haematological adverse reaction, in less than 1% of users. To improve safety, the drug is subject to mandatory haematological monitoring throughout the course of treatment, which is burdensome for the patient and one of the main reasons clozapine is underused. Therefore, a pharmacogenetic test is clinically useful if it identifies a group of patients for whom the agranulocytosis risk is low enough to alleviate monitoring requirements. Assuming a genotypic marker stratifies patients into a high-risk and a low-risk group, we explore the relationship between test sensitivity, group size and agranulocytosis risk. High sensitivity minimizes the agranulocytosis risk in the low-risk group and is essential for clinical utility, in particular in combination with a small high-risk group.
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Affiliation(s)
- M Verbelen
- SGDP Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - D A Collier
- SGDP Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Discovery Neuroscience Research, Eli Lilly and Company Ltd, Lilly Research Laboratories, Erl Wood Manor, Surrey, UK
| | - D Cohen
- Department of Severe Mental Illness, Mental Health Care Organization North-Holland North, Heerhugowaard, The Netherlands
| | - J H MacCabe
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - C M Lewis
- SGDP Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Department of Medical and Molecular Genetics, King's College London, London, UK
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