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Llorca-Bofí V, Bioque M, Madero S, Mallorquí A, Oliveira C, Garriga M, Parellada E, García-Rizo C. Blood Cell Count Ratios at Baseline are Associated with Initial Clinical Response to Clozapine in Treatment-Resistant, Clozapine-Naïve, Schizophrenia-Spectrum Disorder. PHARMACOPSYCHIATRY 2024; 57:173-179. [PMID: 38621701 DOI: 10.1055/a-2290-6386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
BACKGROUND Clozapine is the recommended treatment for managing treatment-resistant schizophrenia (TRS), and immunological mechanisms may be involved in its unique antipsychotic efficacy. This study investigated whether baseline immune abnormalities measured with blood cell count ratios can predict the clinical response after initiating treatment with clozapine in patients with clozapine naïve TRS. METHODS A longitudinal design was developed, involving 32 patients diagnosed with treatment-resistant, clozapine-naïve schizophrenia-spectrum disorder. Patients were evaluated at baseline before clozapine starting and 8 weeks of follow-up. Psychopathological status and immune abnormalities (blood cell count ratios: neutrophil-lymphocyte ratio [NLR], monocyte-lymphocyte ratio [MLR], platelet-lymphocyte ratio [PLR] and basophil-lymphocyte ratio [BLR]) were evaluated in each visit. RESULTS Baseline NLR (b=- 0.364; p=0.041) and MLR (b =- 0.400; p=0.023) predicted the change in positive symptoms over the 8-week period. Patients who exhibited a clinical response showed higher baseline NLR (2.38±0.96 vs. 1.75±0.83; p=0.040) and MLR (0.21±0.06 vs. 0.17±0.02; p=0.044) compared to non-responders. In the ROC analysis, the threshold points to distinguish between responders and non-responders were approximately 1.62 for NLR and 0.144 for MLR, yielding AUC values of 0.714 and 0.712, respectively. No statistically significant differences were observed in the blood cell count ratios from baseline to the 8-week follow-up. CONCLUSION Our study emphasizes the potential clinical significance of baseline NLR and MLR levels as predictors of initial clozapine treatment response in patients with TRS. Future studies with larger sample sizes and longer follow-up periods should replicate our findings.
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Affiliation(s)
- Vicent Llorca-Bofí
- Department of Medicine, University of Barcelona, Barcelona, Spain
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Miquel Bioque
- Department of Medicine, University of Barcelona, Barcelona, Spain
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Santiago Madero
- Department of Medicine, University of Barcelona, Barcelona, Spain
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Andrea Mallorquí
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | | | - Marina Garriga
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
- Bipolar and Depressive Disorders Unit, Neurosciences Institute, Hospital Clínic Barcelona, Barcelona, Spain
| | - Eduard Parellada
- Department of Medicine, University of Barcelona, Barcelona, Spain
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Clemente García-Rizo
- Department of Medicine, University of Barcelona, Barcelona, Spain
- Barcelona Clínic Schizophrenia Unit (BCSU), Neuroscience Institute, Hospital Clínic de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- University of Coimbra, Coimbra, Portugal
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Sernoskie SC, Bonneil É, Thibault P, Jee A, Uetrecht J. Involvement of Extracellular Vesicles in the Proinflammatory Response to Clozapine: Implications for Clozapine-Induced Agranulocytosis. J Pharmacol Exp Ther 2024; 388:827-845. [PMID: 38262745 DOI: 10.1124/jpet.123.001970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/27/2023] [Accepted: 12/08/2023] [Indexed: 01/25/2024] Open
Abstract
Most idiosyncratic drug reactions (IDRs) appear to be immune-mediated, but mechanistic events preceding severe reaction onset remain poorly defined. Damage-associated molecular patterns (DAMPs) may contribute to both innate and adaptive immune phases of IDRs, and changes in extracellular vesicle (EV) cargo have been detected post-exposure to several IDR-associated drugs. To explore the hypothesis that EVs are also a source of DAMPs in the induction of the immune response preceding drug-induced agranulocytosis, the proteome and immunogenicity of clozapine- (agranulocytosis-associated drug) and olanzapine- (non-agranulocytosis-associated drug) exposed EVs were compared in two preclinical models: THP-1 macrophages and Sprague-Dawley rats. Compared with olanzapine, clozapine induced a greater increase in the concentration of EVs enriched from both cell culture media and rat serum. Moreover, treatment of drug-naïve THP-1 cells with clozapine-exposed EVs induced an inflammasome-dependent response, supporting a potential role for EVs in immune activation. Proteomic and bioinformatic analyses demonstrated an increased number of differentially expressed proteins with clozapine that were enriched in pathways related to inflammation, myeloid cell chemotaxis, wounding, transforming growth factor-β signaling, and negative regulation of stimuli response. These data indicate that, although clozapine and olanzapine exposure both alter the protein cargo of EVs, clozapine-exposed EVs carry mediators that exhibit significantly greater immunogenicity. Ultimately, this supports the working hypothesis that drugs associated with a risk of IDRs induce cell stress, release of proinflammatory mediators, and early immune activation that precedes severe reaction onset. Further studies characterizing EVs may elucidate biomarkers that predict IDR risk during development of drug candidates. SIGNIFICANCE STATEMENT: This work demonstrates that clozapine, an idiosyncratic drug-induced agranulocytosis (IDIAG)-associated drug, but not olanzapine, a safer structural analogue, induces an acute proinflammatory response and increases extracellular vesicle (EV) release in two preclinical models. Moreover, clozapine-exposed EVs are more immunogenic, as measured by their ability to activate inflammasomes, and contain more differentially expressed proteins, highlighting a novel role for EVs during the early immune response to clozapine and enhancing our mechanistic understanding of IDIAG and other idiosyncratic reactions.
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Affiliation(s)
- Samantha Christine Sernoskie
- Departments of Pharmaceutical Sciences, Faculty of Pharmacy (S.C.S., J.U.) and Pharmacology and Toxicology, Temerty Faculty of Medicine (A.J., J.U.), University of Toronto, Toronto, Ontario; and Institute for Research in Immunology and Cancer (É.B., P.T.) and Department of Chemistry (P.T.), University of Montreal, Montreal, Quebec
| | - Éric Bonneil
- Departments of Pharmaceutical Sciences, Faculty of Pharmacy (S.C.S., J.U.) and Pharmacology and Toxicology, Temerty Faculty of Medicine (A.J., J.U.), University of Toronto, Toronto, Ontario; and Institute for Research in Immunology and Cancer (É.B., P.T.) and Department of Chemistry (P.T.), University of Montreal, Montreal, Quebec
| | - Pierre Thibault
- Departments of Pharmaceutical Sciences, Faculty of Pharmacy (S.C.S., J.U.) and Pharmacology and Toxicology, Temerty Faculty of Medicine (A.J., J.U.), University of Toronto, Toronto, Ontario; and Institute for Research in Immunology and Cancer (É.B., P.T.) and Department of Chemistry (P.T.), University of Montreal, Montreal, Quebec
| | - Alison Jee
- Departments of Pharmaceutical Sciences, Faculty of Pharmacy (S.C.S., J.U.) and Pharmacology and Toxicology, Temerty Faculty of Medicine (A.J., J.U.), University of Toronto, Toronto, Ontario; and Institute for Research in Immunology and Cancer (É.B., P.T.) and Department of Chemistry (P.T.), University of Montreal, Montreal, Quebec
| | - Jack Uetrecht
- Departments of Pharmaceutical Sciences, Faculty of Pharmacy (S.C.S., J.U.) and Pharmacology and Toxicology, Temerty Faculty of Medicine (A.J., J.U.), University of Toronto, Toronto, Ontario; and Institute for Research in Immunology and Cancer (É.B., P.T.) and Department of Chemistry (P.T.), University of Montreal, Montreal, Quebec
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Griffiths K, Mellado MR, Chung R, Lally J, McQueen G, Sendt KV, Gillespie A, Ibrahim M, Richter A, Shields A, Ponsford M, Jolles S, Hodsoll J, Pollak TA, Upthegrove R, Egerton A, MacCabe JH. Changes in immunoglobulin levels during clozapine treatment in schizophrenia. Brain Behav Immun 2024; 115:223-228. [PMID: 37832895 DOI: 10.1016/j.bbi.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/20/2023] [Accepted: 10/06/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND AND HYPOTHESIS Use of clozapine in treatment-resistant schizophrenia is often limited due to risk of adverse effects. Cross-sectional associations between clozapine treatment and low immunoglobulin levels have been reported, however prospective studies are required to establish temporal relationships. We tested the hypothesis that reductions in immunoglobulin levels would occur over the first 6 months following initiation of clozapine treatment. Relationships between immunoglobulin levels and symptom severity over the course of clozapine treatment were also explored. DESIGN This prospective observational study measured immunoglobulin (Ig) levels (A, M and G) in 56 patients with treatment-resistant schizophrenia at 6-, 12- and 24-weeks following initiation with clozapine. Clinical symptoms were also measured at 12 weeks using the positive and negative syndrome scale (PANSS). RESULTS IgA, IgG and IgM all decreased during clozapine treatment. For IgA and IgG the reduction was significant at 24 weeks (IgA: β = -32.66, 95% CI = -62.38, -2.93, p = 0.03; IgG: β = -63.96, 95% CI = -118.00, -9.31, p = 0.02). For IgM the reduction was significant at 12 and 24 weeks (12 weeks: β = -23.48, 95% CI = -39.56, -7.42, p = 0.004; 24 weeks: β = -33.12, 95 %CI = -50.30, -15.94, p = <0.001). Reductions in IgA and IgG during clozapine treatment were correlated with reductions in PANSS-total over 12 weeks (n = 32, IgA r = 0.59, p = 0.005; IgG r = 0.48, p = 0.03). CONCLUSIONS The observed reductions in immunoglobulin levels over six months of clozapine treatment add further evidence linking clozapine to secondary antibody deficiency. Associations between Ig reduction and symptom improvement may however indicate that immune mechanisms contribute to both desirable and undesirable effects of clozapine.
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Affiliation(s)
- Kira Griffiths
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - Maria Ruiz Mellado
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - Raymond Chung
- Department of Social Genetic and Developmental Psychiatry, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - John Lally
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK; Department of Psychiatry, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland; Department of Psychiatry, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Grant McQueen
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - Kyra-Verena Sendt
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | | | - Muhammad Ibrahim
- Department of Immunobiology, Faculty of Life Sciences and Medicine, King's College London, UK
| | - Alex Richter
- Institute of Immunology and Immunotherapy, University of Birmingham, UK
| | - Adrian Shields
- Institute of Immunology and Immunotherapy, University of Birmingham, UK
| | - Mark Ponsford
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK; Henry Wellcome Building, School of Medicine, Cardiff University, Cardiff, UK
| | - Stephen Jolles
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK
| | - John Hodsoll
- Department of Biostatistics and Health Informatics, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - Thomas A Pollak
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - Rachel Upthegrove
- Institute for Mental Health, University of Birmingham, UK; Early Intervention Service, Birmingham Womens and Childrens NHS Foundation Trust, UK
| | - Alice Egerton
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK
| | - James H MacCabe
- Department of Psychosis Studies, Institute of Psychiatry Psychology and Neuroscience, King's College London, UK.
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Tanaka R, Yamada K. Genomic and Reverse Translational Analysis Discloses a Role for Small GTPase RhoA Signaling in the Pathogenesis of Schizophrenia: Rho-Kinase as a Novel Drug Target. Int J Mol Sci 2023; 24:15623. [PMID: 37958606 PMCID: PMC10648424 DOI: 10.3390/ijms242115623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023] Open
Abstract
Schizophrenia is one of the most serious psychiatric disorders and is characterized by reductions in both brain volume and spine density in the frontal cortex. RhoA belongs to the RAS homolog (Rho) family and plays critical roles in neuronal development and structural plasticity via Rho-kinase. RhoA activity is regulated by GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs). Several variants in GAPs and GEFs associated with RhoA have been reported to be significantly associated with schizophrenia. Moreover, several mouse models carrying schizophrenia-associated gene variants involved in RhoA/Rho-kinase signaling have been developed. In this review, we summarize clinical evidence showing that variants in genes regulating RhoA activity are associated with schizophrenia. In the last half of the review, we discuss preclinical evidence indicating that RhoA/Rho-kinase is a potential therapeutic target of schizophrenia. In particular, Rho-kinase inhibitors exhibit anti-psychotic-like effects not only in Arhgap10 S490P/NHEJ mice, but also in pharmacologic models of schizophrenia (methamphetamine- and MK-801-treated mice). Accordingly, we propose that Rho-kinase inhibitors may have antipsychotic effects and reduce cognitive deficits in schizophrenia despite the presence or absence of genetic variants in small GTPase signaling pathways.
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Affiliation(s)
- Rinako Tanaka
- Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, Nagoya 466-8560, Japan;
| | - Kiyofumi Yamada
- Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, Nagoya 466-8560, Japan;
- International Center for Brain Science (ICBS), Fujita Health University, Toyoake 470-1192, Japan
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5
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Jones R, Morales-Munoz I, Shields A, Blackman G, Legge SE, Pritchard M, Kornblum D, MacCabe JH, Upthegrove R. Early neutrophil trajectory following clozapine may predict clozapine response - Results from an observational study using electronic health records. Brain Behav Immun 2023; 113:267-274. [PMID: 37494985 DOI: 10.1016/j.bbi.2023.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/11/2023] [Accepted: 07/22/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Clozapine has unique effectiveness in treatment-resistant schizophrenia and is known to cause immunological side-effects. A transient spike in neutrophils commonly occurs in the first weeks of clozapine therapy. There is contradictory evidence in the literature as to whether neutrophil changes with clozapine are linked to treatment response. AIMS The current study aims to further examine the neutrophil changes in response to clozapine and explore any association between neutrophil trajectory and treatment response. METHODS A retrospective cohort study of patients undergoing their first treatment with clozapine and continuing for at least 2 years identified 425 patients (69% male/31% female). Neutrophil counts at baseline, 3 weeks and 1 month were obtained predominantly by linkage with data from the clozapine monitoring service. Clinical Global Impression- Severity (CGI-S) was rated from case notes at the time of clozapine initiation and at 2 years. Latent class growth analysis (LCGA) was performed to define distinct trajectories of neutrophil changes during the first month of treatment. Logistic regression was then conducted to investigate for association between the trajectory of neutrophil count changes in month 1 and clinical response at 2 years as well as between baseline neutrophil count and response. RESULTS Of the original cohort, 397 (93%) patients had useable neutrophil data during the first 6 weeks of clozapine treatment. LCGA revealed significant differences in neutrophil trajectories with a three-class model being the most parsimonious. The classes had similar trajectory profiles but differed primarily on overall neutrophil count: with low, high-normal and high neutrophil classes, comprising 52%, 40% and 8% of the sample respectively. Membership of the high-normal group was associated with significantly increased odds of a positive response to clozapine, as compared to the low neutrophil group [Odds ratio (OR) = 2.10, p-value = 0.002; 95% confidence interval (95% CI) = 1.31-3.36]. Baseline neutrophil count was a predictor of response to clozapine at 2 years, with counts of ≥5 × 109/l significantly associated with positive response (OR = 1.60, p-value = 0.03; 95% CI = 1.03-2.49). CONCLUSIONS Our data are consistent with the hypothesis that patients with low-level inflammation, reflected in a high-normal neutrophil count, are more likely to respond to clozapine, raising the possibility that clozapine exerts its superior efficacy via immune mechanisms.
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Affiliation(s)
- Rowena Jones
- Institute for Mental Health, School of Psychology, University of Birmingham, UK; Birmingham and Solihull Mental Health Foundation Trust, UK.
| | | | - Adrian Shields
- Clinical Immunology Service, University of Birmingham, UK
| | - Graham Blackman
- Department of Psychiatry, University of Oxford, Warneford Hospital, OX3 7JX, UK; Department of Psychosis Studies, King's College London, and South London and Maudsley NHS Foundation Trust, UK
| | - Sophie E Legge
- Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Daisy Kornblum
- King's College London (Institute of Psychiatry, Psychology and Neuroscience), London, UK
| | - James H MacCabe
- King's College London (Institute of Psychiatry, Psychology and Neuroscience), London, UK; Department of Psychosis Studies, King's College London, and South London and Maudsley NHS Foundation Trust, UK
| | - Rachel Upthegrove
- Institute for Mental Health, School of Psychology, University of Birmingham, UK; Early Intervention Service, Birmingham Women's and Children's NHS Trust, UK
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The Role of Myeloperoxidase in Clozapine-Induced Inflammation: A Mechanistic Update for Idiosyncratic Drug-Induced Agranulocytosis. Int J Mol Sci 2023; 24:ijms24021243. [PMID: 36674761 PMCID: PMC9862306 DOI: 10.3390/ijms24021243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
The risk of idiosyncratic drug-induced agranulocytosis (IDIAG) markedly constrains the use of clozapine, a neuroleptic with unparalleled efficacy. Most clozapine patients experience an early inflammatory response, likely a necessary step in IDIAG onset. However, most patients do not progress to IDIAG, presumably because of the requirement of specific human leukocyte antigen (HLA) haplotypes, T cell receptors, and other unknown factors. We established that clozapine activates inflammasomes and that myeloperoxidase bioactivation of clozapine generates neoantigens, but the connection between these early mechanistic events remained unknown and, thus, was the aim of this work. We found that the myeloperoxidase inhibitor PF-1355 attenuated myeloperoxidase activity in phorbol myristate acetate (PMA)-differentiated THP-1 macrophages, and it also attenuated clozapine-induced release of inflammatory mediators (e.g., IL-1β, CXCL1, and C-reactive protein). In vivo, pretreatment of Sprague Dawley rats with PF-1355 significantly attenuated clozapine-induced increases in neutrophil mobilization from the bone marrow to the blood and spleen, as determined using differential blood counts and flow cytometry. Moreover, the clozapine-triggered release of inflammatory mediators (e.g., IL-1β, calprotectin, CXCL1, and α-1-acid glycoprotein) from the liver, spleen, and bone marrow was dampened by myeloperoxidase inhibition. These data support the working hypothesis that oxidation of clozapine to a reactive metabolite by myeloperoxidase is critical for induction of the inflammatory response to clozapine. Ultimately, a better mechanistic understanding of the early events involved in the immune response to clozapine may elucidate ways to prevent IDIAG, enabling safer, more frequent therapeutic use of this and potentially other highly efficacious drugs.
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McColl ER, Croyle MA, Zamboni WC, Honer WG, Heise M, Piquette-Miller M, Goralski KB. COVID-19 Vaccines and the Virus: Impact on Drug Metabolism and Pharmacokinetics. Drug Metab Dispos 2023; 51:130-141. [PMID: 36273826 PMCID: PMC11022893 DOI: 10.1124/dmd.122.000934] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/07/2022] [Accepted: 09/30/2022] [Indexed: 01/08/2023] Open
Abstract
This article reports on an American Society of Pharmacology and Therapeutics, Division of Drug Metabolism and Disposition symposium held at Experimental Biology on April 2, 2022, in Philadelphia. As of July 2022, over 500 million people have been infected with SARS-CoV-2 (the virus causing COVID-19) and over 12 billion vaccine doses have been administered. Clinically significant interactions between viral infections and hepatic drug metabolism were first recognized over 40 years ago during a cluster of pediatric theophylline toxicity cases attributed to reduced hepatic drug metabolism amid an influenza B outbreak. Today, a substantive body of research supports that the activated innate immune response generally decreases hepatic cytochrome P450 activity. The interactions extend to drug transporters and other organs and have the potential to impact drug absorption, distribution, metabolism, and excretion (ADME). Based on this knowledge, altered ADME is predicted with SARS-CoV-2 infection or vaccination. The report begins with a clinical case exploring the possibility of SARS-CoV-2 vaccination increasing clozapine levels. This is followed by discussions of how SARS-CoV-2 infection or vaccines alter the metabolism and disposition of complex drugs, such as nanoparticles and biologics and small molecule therapies. The review concludes with a discussion of the effects of viral infections on placental amino acid transport and their potential to impact fetal development. The session improved our understanding of the impact of emerging viral infections and vaccine technologies on drug metabolism and disposition, which will help mitigate drug toxicity and improve drug and vaccine safety and effectiveness. SIGNIFICANCE STATEMENT: Altered pharmacokinetics of small molecule and complex molecule drugs and fetal brain distribution of amino acids following SARS-CoV-2 infection or immunization are possible. The proposed mechanisms involve decreased liver cytochrome P450 metabolism of small molecules, enhanced innate immune system metabolism of complex molecules, and altered placental and fetal blood-brain barrier amino acid transport, respectively. Future research is needed to understand the effects of these interactions on adverse drug responses, drug and vaccine safety, and effectiveness and fetal neurodevelopment.
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Affiliation(s)
- Eliza R McColl
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - Maria A Croyle
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - William C Zamboni
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - William G Honer
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - Mark Heise
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - Micheline Piquette-Miller
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
| | - Kerry B Goralski
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada (E.R.M., M.P-M.); Department of Molecular Pharmaceutics and Drug Delivery and LaMontagne Center for Infectious Disease, University of Texas at Austin, College of Pharmacy, Austin, Texas (M.A.C.); Eshelman School of Pharmacy (W.C.Z.) and Department of Genetics, Department of Microbiology and Immunology, and The Rapidly Emerging Antiviral Drug Development Initiative (READDI) (M.H.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry, University of British Columbia and British Columbia Mental Health and Substance Use Services Research Institute, Vancouver, British Columbia, Canada (W.G.H.); and College of Pharmacy, Faculty of Health and Department of Pharmacology and Department of Pediatrics, Faculty of Medicine, Dalhousie University (K.B.G.); Division of Pediatric Hematology and Oncology, Department of Pediatrics, IWK Health Centre (K.B.G.); and Beatrice Hunter Cancer Research Institute (K.B.G.), Halifax, Nova Scotia, Canada
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8
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Stelmach A, Guzek K, Rożnowska A, Najbar I, Sadakierska-Chudy A. Antipsychotic drug-aripiprazole against schizophrenia, its therapeutic and metabolic effects associated with gene polymorphisms. Pharmacol Rep 2023; 75:19-31. [PMID: 36526889 PMCID: PMC9889418 DOI: 10.1007/s43440-022-00440-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022]
Abstract
Second-generation antipsychotics are widely used for the treatment of schizophrenia. Aripiprazole (ARI) is classified as a third-generation antipsychotic drug with a high affinity for dopamine and serotonin receptors. It is considered a dopamine-system stabilizer without severe side effects. In some patients the response to ARI treatment is inadequate and they require an effective augmentation strategy. It has been found that the response to the drug and the risk of adverse metabolic effects can be related to gene polymorphisms. A reduced dose is recommended for CYP2D6 poor metabolizers; moreover, it is postulated that other polymorphisms including CYP3A4, CYP3A5, ABCB1, DRD2, and 5-HTRs genes influence the therapeutic effect of ARI. ARI can increase the levels of prolactin, C-peptide, insulin, and/or cholesterol possibly due to specific genetic variants. It seems that a pharmacogenetic approach can help predict drug response and improve the clinical management of patients with schizophrenia.
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Affiliation(s)
- Adriana Stelmach
- Department of Genetics, Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzinskiego 1, 30-705, Krakow, Poland
| | - Katarzyna Guzek
- Department of Genetics, Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzinskiego 1, 30-705, Krakow, Poland
| | - Alicja Rożnowska
- Department of Genetics, Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzinskiego 1, 30-705, Krakow, Poland
| | - Irena Najbar
- Centre of Education, Research and Development, Babinski University Hospital, Krakow, Poland
| | - Anna Sadakierska-Chudy
- Department of Genetics, Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzinskiego 1, 30-705, Krakow, Poland.
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9
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Jiao S, Cao T, Cai H. Peripheral biomarkers of treatment-resistant schizophrenia: Genetic, inflammation and stress perspectives. Front Pharmacol 2022; 13:1005702. [PMID: 36313375 PMCID: PMC9597880 DOI: 10.3389/fphar.2022.1005702] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Treatment-resistant schizophrenia (TRS) often results in severe disability and functional impairment. Currently, the diagnosis of TRS is largely exclusionary and emphasizes the improvement of symptoms that may not be detected early and treated according to TRS guideline. As the gold standard, clozapine is the most prescribed selection for TRS. Therefore, how to predict TRS in advance is critical for forming subsequent treatment strategy especially clozapine is used during the early stage of TRS. Although mounting studies have identified certain clinical factors and neuroimaging characteristics associated with treatment response in schizophrenia, the predictors for TRS remain to be explored. Biomarkers, particularly for peripheral biomarkers, show great potential in predicting TRS in view of their predictive validity, noninvasiveness, ease of testing and low cost that would enable their widespread use. Recent evidence supports that the pathogenesis of TRS may be involved in abnormal neurotransmitter systems, inflammation and stress. Due to the heterogeneity of TRS and the lack of consensus in diagnostic criteria, it is difficult to compare extensive results among different studies. Based on the reported neurobiological mechanisms that may be associated with TRS, this paper narratively reviews the updates of peripheral biomarkers of TRS, from genetic and other related perspectives. Although current evidence regarding biomarkers in TRS remains fragmentary, when taken together, it can help to better understand the neurobiological interface of clinical phenotypes and psychiatric symptoms, which will enable individualized prediction and therapy for TRS in the long run.
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Affiliation(s)
- Shimeng Jiao
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
| | - Ting Cao
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
| | - Hualin Cai
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
- *Correspondence: Hualin Cai,
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SOC-IV-04 DAMPening the immune response to clozapine: the role of reactive metabolites in idiosyncratic drug reactions. Toxicol Lett 2022. [DOI: 10.1016/j.toxlet.2022.07.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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Antipsychotic-like effects of fasudil, a Rho-kinase inhibitor, in a pharmacologic animal model of schizophrenia. Eur J Pharmacol 2022; 931:175207. [PMID: 35987254 DOI: 10.1016/j.ejphar.2022.175207] [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: 05/29/2022] [Revised: 08/07/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022]
Abstract
Current antipsychotics used to treat schizophrenia have associated problems, including serious side effects and treatment resistance. We recently identified a significant association of schizophrenia with exonic copy number variations in the Rho GTPase activating protein 10 (ARHGAP10) gene using genome-wide analysis. ARHGAP10 encodes a RhoGAP superfamily member that is involved in small GTPase signaling. In mice, Arhgap10 gene variations result in RhoA/Rho-kinase pathway activation. We evaluated the pharmacokinetics of fasudil and hydroxyfasudil using liquid chromatography-tandem mass spectrometry in mice. The antipsychotic effects of fasudil on hyperlocomotion, social interaction deficits, prepulse inhibition deficits, and novel object recognition deficits were also investigated in a MK-801-treated pharmacological mouse schizophrenia model. Fasudil and its major metabolite, hydroxyfasudil, were detected in the brain at concentrations above their respective Ki values for Rho-kinase after intraperitoneal injection of 10 mg kg-1 fasudil. Fasudil improved the hyperlocomotion, social interaction deficits, prepulse inhibition deficits, and novel object recognition deficits in MK-801-treated mice in a dose-dependent manner. Following oral administration of fasudil, brain hydroxyfasudil was detected at concentration above the Ki value for Rho-kinase whilst fasudil was undetectable. MK-801-induced hyperlocomotion was also improved by oral fasudil administration. These results suggest that fasudil has antipsychotic-like effects on the MK-801-treated pharmacological mouse schizophrenia model. There are two isoforms in Rho-kinase, and further investigation is needed to clarify the isoforms involved in the antipsychotic-like effects of fasudil in the MK-801-treated mouse schizophrenia model.
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12
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Distinctive pattern of neutrophil count change in clozapine-associated, life-threatening agranulocytosis. NPJ SCHIZOPHRENIA 2022; 8:21. [PMID: 35288577 PMCID: PMC8920060 DOI: 10.1038/s41537-022-00232-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/11/2022] [Indexed: 12/19/2022]
Abstract
The wider use of clozapine is limited by the risk of agranulocytosis and the associated requirement for monitoring of neutrophil counts. We searched local electronic patient records for cases of agranulocytosis occurring during clozapine treatment during the period 2007–2020. We found 23 episodes recorded as agranulocytosis in clozapine patients. Of these, nine met pre-defined criteria and were considered episodes of life-threatening agranulocytosis (LTA). These episodes of clozapine-induced LTA exhibited a distinct pattern of continuous and rapid neutrophil count decline to zero or near zero. Mean time for neutrophils to fall from ANC > 2 to ANC <0.5 × 109/L was 8.4 days (range 2–15 days). Each event was also characterised by a prolonged nadir and delayed recovery (range 4–16 days). Non-LTA episodes were, in contrast, brief and benign. We conclude that an important proportion of cases of agranulocytosis identified in people prescribed clozapine are not life-threatening and may not even be clozapine-related. Monitoring schemes should aim to identify true clozapine-induced LTA as opposed to threshold-defined nominal agranulocytosis. Genetics studies might benefit from examining associations with clozapine-induced LTA rather than with recorded cases of agranulocytosis or neutropenia.
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Sernoskie SC, Lobach AR, Kato R, Jee A, Weston JK, Uetrecht J. Clozapine induces an acute proinflammatory response that is attenuated by inhibition of inflammasome signaling: implications for idiosyncratic drug-induced agranulocytosis. Toxicol Sci 2021; 186:70-82. [PMID: 34935985 PMCID: PMC8883353 DOI: 10.1093/toxsci/kfab154] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Although clozapine is a highly efficacious schizophrenia treatment, it is under-prescribed due to the risk of idiosyncratic drug-induced agranulocytosis (IDIAG). Clinical data indicate that most patients starting clozapine experience a transient immune response early in treatment and a similar response has been observed in clozapine-treated rats, but the mechanism by which clozapine triggers this transient inflammation remains unclear. Therefore, the aim of this study was to characterize the role of inflammasome activation during the early immune response to clozapine using in vitro and in vivo models. In both differentiated and nondifferentiated human monocytic THP-1 cells, clozapine, but not its structural analogues fluperlapine and olanzapine, caused inflammasome-dependent caspase-1 activation and IL-1β release that was inhibited using the caspase-1 inhibitor yVAD-cmk. In Sprague Dawley rats, a single dose of clozapine caused an increase in circulating neutrophils and a decrease in lymphocytes within hours of drug administration along with transient spikes in the proinflammatory mediators IL-1β, CXCL1, and TNF-α in the blood, spleen, and bone marrow. Blockade of inflammasome signaling using the caspase-1 inhibitor VX-765 or the IL-1 receptor antagonist anakinra attenuated this inflammatory response. These data indicate that caspase-1-dependent IL-1β production is fundamental for the induction of the early immune response to clozapine and, furthermore, support the general hypothesis that inflammasome activation is a common mechanism by which drugs associated with the risk of idiosyncratic reactions trigger early immune system activation. Ultimately, inhibition of inflammasome signaling may reduce the risk of IDIAG, enabling safer, more frequent use of clozapine in patients.
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Affiliation(s)
| | - Alexandra R Lobach
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Ryuji Kato
- Department of Cardiovascular Pharmacotherapy and Toxicology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Osaka, 569-1094, Japan
| | - Alison Jee
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - J Kyle Weston
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Jack Uetrecht
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada.,Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
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14
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Baig AI, Bazargan-Hejazi S, Ebrahim G, Rodriguez-Lara J. Clozapine prescribing barriers in the management of treatment-resistant schizophrenia: A systematic review. Medicine (Baltimore) 2021; 100:e27694. [PMID: 34766570 PMCID: PMC10545051 DOI: 10.1097/md.0000000000027694] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/30/2021] [Accepted: 10/20/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Treatment-resistant schizophrenia is prevalent and difficult to manage, as patients fail multiple antipsychotic trials before being considered as treatment-resistant. Currently clozapine is the only Food and Drug Administration-approved pharmacotherapy for treatment-resistant schizophrenia but remains under-prescribed. The purpose of this study is to investigate recent literature on clozapine in order to identify barriers to prescribing clozapine and categorize the recommended solutions. METHODS We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Using free text and the medical subject headings, we searched MEDLINE/PubMed electronic bibliographic database from 2017 until 2020. Eligible studies included peer-reviewed English language articles with multiple methodologies aiming to identify clozapine barriers in treatment-resistant schizophrenia. We used search terms combining clozapine AND treatment OR treatment-resistant schizophrenia AND barriers AND prescribing OR prescription OR prescriber. We merged search results in a citation manager software, removed duplicates, and screened the remaining articles based on the study eligibility criteria. RESULTS We retrieved 123 studies, however, only 10 articles exclusively met the study inclusion criteria for full text review. These studies represented 20 countries; 6 were exclusively conducted in the US. The top barriers delineated by the studies include: providers' lack of knowledge and training (n = 7), concern about side effects (n = 8), and poor adherence (n = 7). All studies described more than 1 barrier. Other barriers included prescriber-perceived barriers (n = 4), administrative barriers (n = 5), and other healthcare systems-related barriers (n = 3). Top recommendations to overcome clozapine prescription barriers included improving prescriber clozapine education/training, utilizing interdisciplinary teams and providing integrated care via clozapine clinics, and simplifying blood test monitoring. CONCLUSION Clozapine remains under-prescribed for patients with treatment-resistant schizophrenia due to multiple barriers related to the individual prescriber, system of care, and technology. It is recommended that by improving prescriber knowledge and training, use of integrated care, and use of technology that can enable continuous, real-time blood test monitoring, these barriers may be overcome.
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Affiliation(s)
- Anum Iqbal Baig
- College of Medicine, Charles R. Drew University of Medicine & Science, Los Angeles, CA
| | - Shahrzad Bazargan-Hejazi
- College of Medicine, Charles R. Drew University of Medicine & Science, Los Angeles, CA
- David Geffen School of Medicine, University of California at Los Angeles, CA
| | - Gul Ebrahim
- College of Medicine, Charles R. Drew University of Medicine & Science, Los Angeles, CA
| | - Jaziel Rodriguez-Lara
- College of Medicine, Charles R. Drew University of Medicine & Science, Los Angeles, CA
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