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Watanabe K, Misaka S, Kanno-Nozaki K, Chiyoda T, Suzuki Y, Sato A, Suto T, Kuroda J, Shimomura K, Miura I, Yabe H. Effect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction mediated by time-dependent inhibition of CYP3A4. Br J Clin Pharmacol 2024; 90:354-359. [PMID: 37596710 DOI: 10.1111/bcp.15889] [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: 04/19/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 08/20/2023] Open
Abstract
Clozapine (CLZ) is extensively used for treatment-resistant schizophrenia (TRS) with caution to avoid serious adverse events such as agranulocytosis and drug-drug interactions (DDIs). In the current report, we present a case of a 35-year-old male non-smoking TRS patient whose steady-state plasma trough concentrations (Ctrough ) of CLZ and its active metabolite, N-desmethylclozapine (NDMC), were significantly increased after initiating oral administration of lemborexant (LEM), a dual orexin receptor antagonist, for the treatment of insomnia. The patient experienced oversedation with sleepiness and fatigue while maintaining high levels of Ctrough of CLZ. The increased concentrations of CLZ returned to normal ranges after the discontinuation of LEM dosing, implying a pharmacokinetic DDI between CLZ and LEM. To gain insight into possible mechanisms, we performed in vitro assays of CYP1A2- and CYP3A4-mediated CLZ metabolism by measuring the formations of NDMC and clozapine N-oxide (CNO). In accordance with previous studies, the incubation of CLZ with each enzyme resulted in the production of both metabolites. LEM had only a weak inhibitory effect on CYP1A2- and CYP3A4-mediated CLZ metabolism. However, the preincubation of LEM with CYP3A4 in the presence of NADPH showed a significant enhancement of inhibitory effects on CLZ metabolism with IC50 values for the formations of CNO and NDMC of 2.8 μM and 4.1 μM, respectively, suggesting that LEM exerts as a potent time-dependent inhibitor for CYP3A4. Taken together, the results of the current study indicate that co-medication of CLZ with LEM may lead to increase in exposure to CLZ and risks of CLZ-related adverse events.
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Affiliation(s)
- Kenya Watanabe
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Shingen Misaka
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
- Department of Bioregulation and Pharmacological Medicine, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Keiko Kanno-Nozaki
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Takaaki Chiyoda
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yuhei Suzuki
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Akiko Sato
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Takahiro Suto
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Junko Kuroda
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Itaru Miura
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hirooki Yabe
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
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Lin SK, Lane HY. A brief history of clozapine use in Taiwan. Schizophr Res 2023:S0920-9964(23)00224-4. [PMID: 37391310 DOI: 10.1016/j.schres.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 07/02/2023]
Abstract
Blood concentrations of clozapine in Taiwanese patients appeared approximately 30-50 % higher than that from Caucasian patients, and women possessed a higher blood levels. Fluvoxamine was reported to increase the clozapine levels, reduce clozapine-related weight gain and metabolic disturbances, and improved general psychopathology. Clothiapine, a chemical structure analogue of clozapine, showed potential of benefitting patients who are unsuitable for clozapine treatment in Taiwan. Obsessive/compulsive symptom (OCS) is a common side effect of clozapine. Concentrations of clozapine were remarkably higher in patients with OCS than in those without. In conclusion, clozapine is a widely used in patients with schizophrenia in Taiwan.
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Affiliation(s)
- Shih-Ku Lin
- Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan; Taipei City Hospital and Psychiatric Center, Taipei, Taiwan
| | - Hsien-Yuan Lane
- Department of Psychiatry and Brain Disease Research Center, China Medical University Hospital, Taichung, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan; Department of Psychology, College of Medical and Health Sciences, Asia University, Taichung, Taiwan.
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3
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Qubad M, Bittner RA. Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia. Ther Adv Psychopharmacol 2023; 13:20451253231158152. [PMID: 36994117 PMCID: PMC10041648 DOI: 10.1177/20451253231158152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/24/2023] [Indexed: 03/31/2023] Open
Abstract
Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.
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Affiliation(s)
- Mishal Qubad
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
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Bellon A, Nguyen K. Selective serotonin reuptake inhibitors and risk reduction for cardiovascular disease in patients with schizophrenia: A controversial but promising approach. World J Psychiatry 2021; 11:316-324. [PMID: 34327124 PMCID: PMC8311507 DOI: 10.5498/wjp.v11.i7.316] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/16/2021] [Accepted: 06/28/2021] [Indexed: 02/06/2023] Open
Abstract
Patients with schizophrenia (SCZ) are at high risk of cardiovascular disease (CVD) due to an inherited predisposition, a sedentary life style and the use of antipsychotic medications. Several approaches have been taken to minimize this risk but results continue to be unsatisfactory. A potential alternative is prescribing selective serotonin reuptake inhibitors (SSRIs). SSRIs decrease platelet aggregation and reduce the risk of coronary heart disease in patients with depression. We therefore aim to investigate whether there is evidence that supports the use of SSRIs to reduce the risk for CVD in SCZ. A review of the literature revealed five published reports relating to the impact of SSRIs on CV risk in SCZ. Three trials assessed the influence on metabolic parameters of fluvoxamine when combined with clozapine. Two of those studies found improvements with fluvoxamine. Of the other two reports, one indicates SSRIs as a group caused minimal but statistically significant increments in total cholesterol, low-density lipoprotein and triglyceride. The second report suggests that when SSRIs are combined with antipsychotics, the metabolic impact depends on the antipsychotic prescribed. While there are promising results, no conclusions can be made currently on whether SSRIs increase or decrease CV risk in SCZ. Further studies are needed to resolve this matter.
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Affiliation(s)
- Alfredo Bellon
- Department of Psychiatry and Behavioral Health, Penn State Hershey Medical Center, Hershey, PA 17033, United States
| | - Kieuhanh Nguyen
- Department of Penn State College of Medicine, Penn State Hershey Medical Center, Hershey, PA 17033, United States
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6
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Pashaei Y. Drug repurposing of selective serotonin reuptake inhibitors: Could these drugs help fight COVID-19 and save lives? J Clin Neurosci 2021; 88:163-172. [PMID: 33992179 PMCID: PMC7973060 DOI: 10.1016/j.jocn.2021.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/05/2021] [Accepted: 03/11/2021] [Indexed: 02/09/2023]
Abstract
The current 2019 novel coronavirus disease (COVID-19), an emerging infectious disease, is undoubtedly the most challenging pandemic in the 21st century. A total of 92,977,768 confirmed cases of COVID-19 and 1,991,289 deaths were reported globally up to January 14, 2021. COVID-19 also affects people's mental health and quality of life. At present, there is no effective therapeutic strategy for the management of this disease. Therefore, in the absence of a specific vaccine or curative treatment, it is an urgent need to identify safe, effective and globally available drugs for reducing COVID-19 morbidity and fatalities. In this review, we focus on selective serotonin reuptake inhibitors (SSRIs: a class of antidepressant drugs with widespread availability and an optimal tolerability profile) that can potentially be repurposed for COVID-19 and are currently being tested in clinical trials. We also summarize the existing literature on what is known about the link between serotonin (5-HT) and the immune system. From the evidence reviewed here, we propose fluoxetine as an adjuvant therapeutic agent for COVID-19 based on its known immunomodulatory, anti-inflammatory and antiviral properties. Fluoxetine may potentially reduce pro-inflammatory chemokine/cytokines levels (such as CCL-2, IL-6, and TNF-α) in COVID-19 patients. Furthermore, fluoxetine may help to attenuate neurological complications of COVID-19.
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Abstract
BACKGROUND Although clozapine is the gold standard for treatment-resistant schizophrenia, more than 30% of patients remain unresponsive to clozapine monotherapy and may benefit from augmentation strategies. Fluvoxamine augmentation of clozapine may be beneficial in treatment resistance because of pharmacokinetic interactions, allowing for lower clozapine dosages with higher clozapine serum levels and an increased clozapine-to-norclozapine ratio, which can modify adverse effects. An augmentation strategy using higher fluvoxamine doses may also improve persistent negative, anxiety, and obsessive-compulsive symptoms through fluvoxamine's serotonergic activity. METHODS Through chart review, we identified 4 cases of patients with treatment-resistant psychosis who underwent high-dose fluvoxamine augmentation of clozapine to target residual negative symptoms, refractory psychosis, anxiety, and obsessive-compulsive symptoms. FINDINGS This augmentation strategy continued in 2 patients after discharge who showed clinical improvement without significant adverse effects. Two patients experienced adverse effects that led to the fluvoxamine discontinuation. Despite the fact that fluvoxamine augmentation led to symptom improvement in only 2 patients, all patients achieved high serum clozapine levels. Hematologic parameters were monitored in all patients, and no abnormalities were observed. No severe adverse effects of clozapine were experienced. CONCLUSIONS Although high variability of responses and adverse effects were observed during fluvoxamine augmentation to clozapine, this strategy was successful in increasing clozapine serum levels. Through fluvoxamine's serotonergic effects, this strategy may confer benefit to residual negative, obsessive, and anxiety symptoms. Limitations of this case series include the retrospective nature, absence of controls, diversity of diagnoses, multiple interventions in each patient, and lack of masked raters.
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Berel C, Mossé U, Wils J, Cousin L, Imbert L, Gerardin P, Chaumette B, Lamoureux F, Ferrafiat V. Interest of Fluvoxamine as an Add-On to Clozapine in Children With Severe Psychiatric Disorder According to CYP Polymorphisms: Experience From a Case Series. Front Psychiatry 2021; 12:669446. [PMID: 34234701 PMCID: PMC8255476 DOI: 10.3389/fpsyt.2021.669446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/21/2021] [Indexed: 01/24/2023] Open
Abstract
Despite its drastic efficacy in resistant psychiatric disorders, clozapine remains rarely used in youth due to its side effects. Clozapine plasma level is determined through its metabolism involving several isoforms of cytochromes 450 (CYP450) family. Isoform CYP1A2 appears as a limiting enzyme involved in the metabolism of clozapine, while isoforms 2C19, 2D6, 3A4, and 3A5 also contribute in a minor way. Clozapine efficacy is limited by a significant inter-patient variability in exposure according to CYP's polymorphisms. Clozapine plasma levels may be increased with CYP inhibitors such as fluvoxamine. This drug is a potent enzymatic inhibitor of CYP1A2 and, to a lesser extent, of CYP3A4 and CYP2D6. Hence, in case of CYP's polymorphisms in youth, the use of fluvoxamine as add-on to clozapine could help in reaching clinical and biological efficacy and allowing lower clozapine dosage and a better tolerance profile as it has already been described in adults. We report four pediatric cases with severe psychiatric disorders underlying our experience with CYP polymorphism explorations and the use of fluvoxamine as add-on to clozapine. Our four patients clinically improved after the introduction of fluvoxamine, enhancing clozapine metabolism and therefore the clozapine plasma level within therapeutic range. Despite the interesting results of fluvoxamine, we report a severe issue of tolerance for one patient, emphasizing the need for caution regarding possible drug interactions when fluvoxamine is considered. Hence, we propose a detailed step-by-step multidisciplinary protocol.
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Affiliation(s)
- Camille Berel
- Child and Adolescent Psychiatric Unit, URHEA, CHSR Sotteville les Rouen, Sotteville les Rouen, France
| | - Ulysse Mossé
- Child and Adolescent Psychiatric Unit, URHEA, CHSR Sotteville les Rouen, Sotteville les Rouen, France
| | - Julien Wils
- Department of Pharmacology - Toxicology and Pharmacogenetics, Rouen University Hospital, Rouen, France.,Normandie Univ, UNIROUEN, Inserm U1096, Rouen, France
| | - Lauriane Cousin
- Child and Adolescent Psychiatric Department, CHRU Lille, Lille, France
| | - Laurent Imbert
- Department of Pharmacology - Toxicology and Pharmacogenetics, Rouen University Hospital, Rouen, France
| | - Priscille Gerardin
- Child and Adolescent Psychiatric Unit, URHEA, CHSR Sotteville les Rouen, Sotteville les Rouen, France.,Child and Adolescent Psychiatric Department, CHU Charles Nicolle, Rouen, France
| | - Boris Chaumette
- Institut de Psychiatrie et Neurosciences de Paris, INSERM UMR 1266, Université de Paris, GDR3557-Institut de Psychiatrie, Paris, France.,GHU Paris Psychiatrie et Neurosciences, Paris, France.,Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Fabien Lamoureux
- Department of Pharmacology - Toxicology and Pharmacogenetics, Rouen University Hospital, Rouen, France.,Normandie Univ, UNIROUEN, Inserm U1096, Rouen, France
| | - Vladimir Ferrafiat
- Child and Adolescent Psychiatric Unit, URHEA, CHSR Sotteville les Rouen, Sotteville les Rouen, France.,Child and Adolescent Psychiatric Department, CHU Charles Nicolle, Rouen, France
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9
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Wagner E, McMahon L, Falkai P, Hasan A, Siskind D. Impact of smoking behavior on clozapine blood levels - a systematic review and meta-analysis. Acta Psychiatr Scand 2020; 142:456-466. [PMID: 32869278 DOI: 10.1111/acps.13228] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Tobacco smoking significantly impacts clozapine blood levels and has substantial implications on individual efficacy and safety outcomes. By investigating differences in clozapine blood levels in smoking and non-smoking patients on clozapine, we aim to provide guidance for clinicians how to adjust clozapine levels for patients on clozapine who change their smoking habits. METHODS We conducted a meta-analysis on clozapine blood levels, norclozapine levels, norclozapine/clozapine ratios, and concentration to dose (C/D) ratios in smokers and non-smokers on clozapine. Data were meta-analyzed using a random-effects model with sensitivity analyses on dose, ethnic origin, and study quality. RESULTS Data from 23 studies were included in this meta-analysis with 21 investigating differences between clozapine blood levels of smokers and non-smokers. In total, data from 7125 samples were included for the primary outcome (clozapine blood levels in ng/ml) in this meta-analysis. A meta-analysis of all between-subject studies (N = 16) found that clozapine blood levels were significantly lower in smokers compared with non-smokers (Standard Mean Difference (SMD) -0.39, 95% confidence interval (CI) -0.55 to -0.22, P < 0.001, I2 = 80%). With regard to the secondary outcome, C/D ratios (N = 16 studies) were significantly lower in the smoker group (n = 645) compared with the non-smoker group (n = 813; SMD -0.70, 95%CI -0.84 to -0.56, P < 0.00001, I2 = 17%). CONCLUSION Smoking behavior and any change in smoking behavior is associated with a substantial effect on clozapine blood levels. Reductions of clozapine dose of 30% are recommended when a patient on clozapine stops smoking. Reductions should be informed by clozapine steady-state trough levels and a close clinical risk-benefit evaluation.
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Affiliation(s)
- E Wagner
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - L McMahon
- School of Medicine, University of Queensland, Brisbane, Australia
| | - P Falkai
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - A Hasan
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics of the University Augsburg, Bezirkskrankenhaus Augsburg, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - D Siskind
- School of Medicine, University of Queensland, Brisbane, Australia.,Metro South Addiction and Mental Health Service, Brisbane, Australia
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de Leon J, Schoretsanitis G, Kane JM, Ruan CJ. Using therapeutic drug monitoring to personalize clozapine dosing in Asians. Asia Pac Psychiatry 2020; 12:e12384. [PMID: 32119764 DOI: 10.1111/appy.12384] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/19/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
This narrative review on clozapine blood levels or therapeutic drug monitoring (TDM) includes sections focused on drug clearance and TDM, personalized dosing with TDM, clinical applications of TDM in Asians, and areas needing further study. Asian patients need half the clozapine dose (D) used in the United States to get the same blood concentrations (C). The concentration-to-dose (C/D) ratio measures drug clearance. In the United States, the average clozapine patient usually needs from 300 to 600 mg/day to reach 350 ng/mL. US male smokers reach this therapeutic C with a D of 600 mg/day (C/D ratio of 0.60 = 600/350), whereas US female nonsmokers usually need a D of 300 mg/day (C/D ratio of 1.17 = 300/350). While in the United States, average CLO C/D ratios typically are 0.6-1.2 ng/mL per mg/day, in Asian populations they range from 1.20 in male smokers to 2.40 in female smokers, requiring Ds of 300 to 150 mg/day to obtain 350 ng/mL. Asian patients can become clozapine poor metabolizers (PMs), needing very low Ds (50-150 mg/day) to get therapeutic Cs, by taking inhibitors (fluvoxamine, oral contraceptives and valproic acid), due to obesity, or during inflammations with systemic effects. In 573 Asian patients from five samples, around 1% were PMs due to taking inhibitors, 1% due to inflammation, 1% due to obesity, and 7% were potential genetic PMs. The potential genetic PMs ranged between 3% and 13%, but this prevalence will have to be better established in future studies including genetic testing for possible CYP1A2 mutations, which may explain PM status.
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Affiliation(s)
- Jose de Leon
- Mental Health Research Center, Eastern State Hospital, Lexington, Kentucky.,Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain.,Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apóstol Hospital, University of the Basque Country, Vitoria, Spain
| | - Georgios Schoretsanitis
- Department of Psychiatry Research, Zucker Hillside Hospital, Northwell Health, Glen Oaks, New York
| | - John M Kane
- Department of Psychiatry Research, Zucker Hillside Hospital, Northwell Health, Glen Oaks, New York.,Department of Psychiatry and Molecular Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York
| | - 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
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Dang TT, Nguyen TH, Ho TB. Causality Assessment of Adverse Drug Reaction: Controlling Confounding Induced by Polypharmacy. Curr Pharm Des 2020; 25:1134-1143. [PMID: 31038058 DOI: 10.2174/1381612825666190416115714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/01/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Post-marketing pharmaceutical surveillance, a.k.a. pragmatic clinical trials (i.e., PCT), plays a vital role in preventing accidents in practical treatment. The most important and difficult task in PCT is to assess which drug causes adverse reactions (i.e., ADRs) from clinical texts. The confounding (i.e., factors cause confusions in causality assessment) is generated by the polypharmacy (i.e., multiple drugs use), which makes most of existing methods poor for detecting drugs that capably cause observed ADRs. OBJECTIVE We aim to improve the performance of detecting drug-ADR causal relations from clinical texts. To this end, a mechanism for reducing the impact of confounding on the detecting process is needful. METHODS We proposed a novel model which is called the analogy-based active voting (i.e., AAV) for improving the ability of detecting causal drug-ADR pairs, in case multiple drugs are prescribed for treating the comorbidity. This model is inspired by the analogy principle which was proposed by Bradford Hill. RESULTS The experimental results show the improvement of recognizing causal relations between drugs and ADRs that are confirmed by the SIDER. In addition, the proposed model is promising to detect infrequently observed causal drug-ADR pairs when the drug is not commonly used. CONCLUSION The proposed model demonstrates its ability for controlling the polypharmacy-induced confounding, to improve the quality of causality assessment of ADRs. Additionally, this also shows that the analogy principle is applicable for the assessment.
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Affiliation(s)
- Tran-Thai Dang
- Japan Advanced Instiute of Science and Technology, 1 Chrome-1 Asahidia, Nomi, Ishikawa 92312211, Japan
| | | | - Tu-Bao Ho
- Japan Advanced Instiute of Science and Technology, 1 Chrome-1 Asahidia, Nomi, Ishikawa 92312211, Japan.,John von Neumann Institute, VNU-HCM, Phurong Linh Trung, Thu Durc, Ho Chi Minh City, Vietnam.,Vietnam Institute for Advanced Study in Mathematics, Hanoi, Vietnam
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Costa-Dookhan KA, Agarwal SM, Chintoh A, Tran VN, Stogios N, Ebdrup BH, Sockalingam S, Rajji TK, Remington GJ, Siskind D, Hahn MK. The clozapine to norclozapine ratio: a narrative review of the clinical utility to minimize metabolic risk and enhance clozapine efficacy. Expert Opin Drug Saf 2019; 19:43-57. [PMID: 31770500 DOI: 10.1080/14740338.2020.1698545] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Introduction: Clozapine remains the most effective antipsychotic for treatment-refractory schizophrenia. However, ~40% of the patients respond insufficiently to clozapine. Clozapine's effects, both beneficial and adverse, have been proposed to be partially attributable to its main metabolite, N-desmethylclozapine (NDMC). However, the relation of the clozapine to norclozapine ratio (CLZ:NDMC; optimally defined as ~2) to clinical response and metabolic outcomes is not clear.Areas covered: This narrative review comprehensively examines the clinical utility of the CLZ:NDMC ratio to reduce metabolic risk and increase treatment efficacy. The association of the CLZ:NDMC ratio with changes in psychopathology, cognitive functioning, and cardiometabolic burden will be explored, as well as adjunctive treatments and their effects.Expert opinion: The literature suggests a positive association between the CLZ:NDMC ratio and better cardiometabolic outcomes. Conversely, the CLZ:NDMC ratio appears inversely associated with better cognitive functioning but less consistently with other psychiatric domains. The CLZ:NDMC ratio may be useful for predicting and monitoring cardiometabolic adverse effects and optimizing potential cognitive benefits of clozapine. Future studies are required to replicate these findings, which if substantiated, would encourage examination of adjunctive treatments aiming to alter the CLZ:NDMC ratio to best meet the needs of the individual patient, thereby broadening clozapine's clinical utility.
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Affiliation(s)
- Kenya A Costa-Dookhan
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Sri Mahavir Agarwal
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Araba Chintoh
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Veronica N Tran
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Nicolette Stogios
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Bjørn H Ebdrup
- Centre for Neuropsychiatric Schizophrenia Research, CNSR & Centre for Clinical Intervention and Neuropsychiatric Schizophrenia Research, CINS, Mental Health Centre Glostrup, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sanjeev Sockalingam
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Tarek K Rajji
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Gary J Remington
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Dan Siskind
- School of Medicine, University of Queensland, Brisbane, Australia.,Schizophrenia Department, Metro South Addiction and Mental Health Service, Brisbane, Australia
| | - Margaret K Hahn
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada
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Abstract
Clozapine is established as the gold standard for antipsychotic treatment of patients suffering from treatment-resistant schizophrenia. Over virtually 3 decades, the level of inadequate response to clozapine was found to range from 40% to 60%. A heightened interest developed in the augmentation of clozapine to try to achieve response or maximize partial response. A large variety of drug groups have been investigated. This article focuses on the meta-analyses of these trials to discover reasonable evidence-based approaches to the management of patients not responding to clozapine.
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Augustin M, Schoretsanitis G, Pfeifer P, Gründer G, Liebe C, Paulzen M. Effect of fluvoxamine augmentation and smoking on clozapine serum concentrations. Schizophr Res 2019; 210:143-148. [PMID: 31182321 DOI: 10.1016/j.schres.2019.05.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/18/2019] [Accepted: 05/26/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND Clozapine (CLZ) is metabolized via cytochrome P450 CYP1A2 to N-desmethylclozapine (NCLZ). Smoking induces CYP1A2 thereby increasing clozapine metabolism whereas fluvoxamine inhibits CYP1A2. Studies suggest that the beneficial effect of fluvoxamine augmentation in raising serum clozapine concentrations also occurs when serum concentrations are low due to smoking. Yet, little is known about the influence of fluvoxamine augmentation on clozapine serum concentrations in smoking versus non-smoking patients. METHODS A TDM database was analyzed. Serum concentrations of CLZ, NCLZ, dose-adjusted serum concentrations (C/D) and metabolite-to-parent ratios (MPR) were compared using non-parametrical tests in four groups: clozapine-monotherapy in non-smokers (VNS, n = 28) and smokers (VS, n = 43); combined treatment with clozapine and fluvoxamine in non-smokers (VNS+F, n = 11) and smokers (VS+F, n = 43). RESULTS The CLZ monotherapy smoking group showed lower values of C/D CLZ of -38.6% (p < 0.001), C/D NCLZ -35.6% (p < 0.001) and a higher MPR (p = 0.021) than in the non-smoking group. The combination of CLZ and fluvoxamine in non-smoking patients led to higher C/D values: C/D CLZ +117.9% (p < 0.001), C/D NCLZ +60.8% (p = 0.029) while the MPR did not differ between groups (p = 0.089). Changes were comparable to fluvoxamine augmentation in the smoking group with increased C/D CLZ of +120.1% (p < 0.001), C/D NCLZ of +85.8% (p < 0.001) and lower MPR (p = 0.006). CONCLUSIONS Smoking in clozapine monotherapy reduced median dose-adjusted serum concentrations more than a third. Combined treatment with fluvoxamine and clozapine led to higher median C/D values in both, smokers and non-smokers. The opposing effects of CYP1A2 induction by smoking and inhibition by fluvoxamine on clozapine serum concentrations balanced out.
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Affiliation(s)
- Marc Augustin
- Department of Psychiatry, Psychotherapy and Psychosomatics, JARA - Translational Brain Medicine, RWTH Aachen University, Aachen, Germany.
| | - Georgios Schoretsanitis
- University Hospital of Psychiatry, Bern, Switzerland; The Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA; Hofstra Northwell School of Medicine, Hempstead, New York and The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Philippe Pfeifer
- University Hospital of Psychiatry Bern, University of Bern, Bern, Switzerland
| | - Gerhard Gründer
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Michael Paulzen
- Department of Psychiatry, Psychotherapy and Psychosomatics, JARA - Translational Brain Medicine, RWTH Aachen University, Aachen, Germany; Alexianer Hospital Aachen, Aachen, Germany
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Population Pharmacokinetics of Clozapine and Norclozapine and Switchability Assessment between Brands in Uruguayan Patients with Schizophrenia. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3163502. [PMID: 30956977 PMCID: PMC6431368 DOI: 10.1155/2019/3163502] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/14/2019] [Indexed: 01/01/2023]
Abstract
Clozapine (CZP) is an atypical antipsychotic agent commonly used in the treatment of schizophrenia. It is metabolized primarily by CYP1A2 enzyme, yielding a pharmacologically active metabolite, norclozapine (NCZP). Significant intra- and interindividual pharmacokinetic (PK) variability for CZP and NCZP has been observed in routine therapeutic drug monitoring. So the goal of this study was to evaluate the magnitude and variability of concentration exposure to CZP and its active metabolite NCZP on pharmacokinetic parameters in Uruguayan patients with schizophrenia with a focus on covariates such as cigarette smoking, age, sex, caffeine consumption, brands available of CZP, and comedication using population PK (PPK) modeling methodologies. Patients with a diagnosis of schizophrenia treated with brand-name CZP (Leponex®) for more than a year were included in the study. Then these patients were switched to the similar brand of CZP (Luverina®). Morning predose blood samples for determination of CZP and NCZP using a HPLC system equipped with a UV detector were withdrawn on both occasions at steady state and under the same comedication. Ninety-eight patients, 22 women and 76 men, took part in the study. Mean ± standard deviation for CZP and NCZP concentration was 421 ± 262 ng/mL and 275 ± 180 ng/mL, respectively. After covariate evaluation, only smoking status remained significant in CZP apparent clearance, inducing a mean increment of 32% but with no clinical impact. The results obtained with the two brands of CZP should ensure comparable efficacy and tolerability with the clinical use of either product. Smoking was significantly associated with a lower exposure to CZP due to higher clearance. The results obtained with the two brands commercialized in our country hint a bioequivalence scenario in the clinical setting.
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Shymko G, Clark V, Shymko L, Waters F. Navigating the co-prescription of clozapine and fluvoxamine. Schizophr Res 2018; 202:391-393. [PMID: 30269927 DOI: 10.1016/j.schres.2018.05.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/16/2018] [Accepted: 05/25/2018] [Indexed: 11/17/2022]
Affiliation(s)
- Gordon Shymko
- South Metropolitan Health Service, Peel and Rockingham Kwinana (PaRK) Mental Health Service, Rockingham, Western Australia 6168, Australia; Headspace Youth Early Psychosis Program (hYEPP), Perth, Western Australia, 6027, Australia.
| | - Vaughan Clark
- North Metropolitan Health Service, Graylands Hospital, Mount Claremont, Western Australia, 6010, Australia
| | - Liana Shymko
- North Metropolitan Health Service, Graylands Hospital, Mount Claremont, Western Australia, 6010, Australia
| | - Flavie Waters
- Headspace Youth Early Psychosis Program (hYEPP), Perth, Western Australia, 6027, Australia; The University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia; North Metropolitan Health Service, Graylands Hospital, Mount Claremont, Western Australia, 6010, Australia
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Effect of Valproate and Antidepressant Drugs on Clozapine Metabolism in Patients With Psychotic Mood Disorders. Ther Drug Monit 2018; 40:443-451. [DOI: 10.1097/ftd.0000000000000513] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lu ML, Chen TT, Kuo PH, Hsu CC, Chen CH. Effects of adjunctive fluvoxamine on metabolic parameters and psychopathology in clozapine-treated patients with schizophrenia: A 12-week, randomized, double-blind, placebo-controlled study. Schizophr Res 2018; 193:126-133. [PMID: 28688742 DOI: 10.1016/j.schres.2017.06.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/17/2017] [Accepted: 06/18/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Numerous studies have demonstrated that fluvoxamine has considerable pharmacokinetic and pharmacodynamic interactions with clozapine. We conducted a 12-week, randomized, double-blind, placebo-controlled study to evaluate the effects of fluvoxamine on metabolic parameters and psychopathology in clozapine-treated patients with schizophrenia. METHODS We recruited 85 patients who received a DSM-IV diagnosis of schizophrenia. Eligible patients were randomized to receive fluvoxamine 50mg/day plus clozapine 100mg/day or clozapine 300mg/day. We studied metabolic parameters, psychopathology, and drug levels at baseline and 4, 8, and 12weeks after the intervention. Plasma levels of clozapine, norclozapine, clozapine N-oxide, and fluvoxamine were determined using high-performance liquid chromatography with ultraviolet detection. RESULTS No significant difference was observed in baseline characteristics between the two groups. Clozapine-fluvoxamine combined treatment significantly attenuated the increments in body weight, insulin resistance, and levels of insulin, glucose, and triglycerides compared with clozapine monotherapy. Both groups exhibited significant improvements in their Positive and Negative Syndrome Scale (PANSS) total and negative scores. The combined treatment group showed significant reduction in the PANSS general psychopathology scores compared with the monotherapy group. No difference was observed in the plasma clozapine level between the two groups. The monotherapy group showed higher levels of norclozapine and clozapine N-oxide than the combined group. CONCLUSIONS Compared with clozapine monotherapy, treatment with adjunctive fluvoxamine with clozapine for 12weeks can alleviate body weight gain and metabolic abnormalities in patients with schizophrenia, without sacrificing the clinical effect. Clinicians should interpret these findings cautiously considering the short duration of this study. The study was registered at www.clinicaltrials.gov (NCT01401491).
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Affiliation(s)
- Mong-Liang Lu
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tzu-Ting Chen
- Department of Psychiatry, National Taiwan University Hospital Yun-Lin Branch, Yunlin County, Taiwan
| | - Po-Hsiu Kuo
- Department of Public Health & Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; Research Center for Genes, Environment and Human Health, National Taiwan University, Taipei, Taiwan
| | - Ching-Chi Hsu
- Department of Psychiatry, Wizcare Hospital, Taichung, Taiwan
| | - Chun-Hsin Chen
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Tóth K, Csukly G, Sirok D, Belic A, Kiss Á, Háfra E, Déri M, Menus Á, Bitter I, Monostory K. Potential Role of Patients' CYP3A-Status in Clozapine Pharmacokinetics. Int J Neuropsychopharmacol 2017; 20:529-537. [PMID: 28340122 PMCID: PMC5492788 DOI: 10.1093/ijnp/pyx019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/17/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The atypical antipsychotic clozapine is effective in treatment-resistant schizophrenia; however, the success or failure of clozapine therapy is substantially affected by the variables that impact the clozapine blood concentration. Thus, elucidating the inter-individual differences in clozapine pharmacokinetics can facilitate the personalized therapy. METHODS Since a potential role in clozapine metabolism is assigned to CYP1A2, CYP2C19, CYP2D6 and CYP3A enzymes, the association between the patients' CYP status (CYP genotypes, CYP expression) and clozapine clearance was evaluated in 92 psychiatric patients. RESULTS The patients' CYP2C19 or CYP2D6 genotypes and CYP1A2 expression seemed to have no effect on clozapine serum concentration, whereas CYP3A4 expression significantly influenced the normalized clozapine concentration (185.53±56.53 in low expressers vs 78.05±29.57 or 66.52±0.25 (ng/mL)/(mg/kg) in normal or high expressers, P<.0001), in particular that the patients expressed CYP1A2 at a relatively low level. The functional CYP3A5*1 allele seemed to influence clozapine concentrations in those patients who expressed CYP3A4 at low levels. The dose requirement for the therapeutic concentration of clozapine was substantially lower in low CYP3A4 expresser patients than in normal/high expressers (2.18±0.64 vs 4.98±1.40 mg/kg, P<.0001). Furthermore, significantly higher plasma concentration ratios of norclozapine/clozapine and clozapine N-oxide/clozapine were observed in the patients displaying normal/high CYP3A4 expression than in the low expressers. CONCLUSION Prospective assaying of CYP3A-status (CYP3A4 expression, CYP3A5 genotype) may better identify the patients with higher risk of inefficiency or adverse reactions and may facilitate the improvement of personalized clozapine therapy; however, further clinical studies are required to prove the benefit of CYP3A testing for patients under clozapine therapy.
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Affiliation(s)
- Katalin Tóth
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Gábor Csukly
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Dávid Sirok
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Ales Belic
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Ádám Kiss
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Edit Háfra
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Máté Déri
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Ádám Menus
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - István Bitter
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
| | - Katalin Monostory
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest Hungary (Ms Tóth, Mr Sirok, Mr Kiss, Ms Háfra, Mr Déri, and Dr Monostory); Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest Hungary (Drs Csukly, Menus, and Bitter); Toxi-Coop Toxicological Research Center, Budapest Hungary (Mr Sirok); University of Ljubljana, Ljubljana Slovenia (Dr Belic)
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Kar N, Barreto S, Chandavarkar R. Clozapine Monitoring in Clinical Practice: Beyond the Mandatory Requirement. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2016; 14:323-329. [PMID: 27776383 PMCID: PMC5083942 DOI: 10.9758/cpn.2016.14.4.323] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/20/2016] [Accepted: 02/21/2016] [Indexed: 01/16/2023]
Abstract
Clozapine is effective in treatment resistant schizophrenia; however, it is underutilised probably because of its side effects. The side effects are also the potential reasons for clozapine discontinuation. A mandatory requirement for its use is regular monitoring of white blood cell count and absolute neutrophil count. However there are many side effects that need monitoring in clinical practice considering their seriousness. This article tries to summarise the clinical concerns surrounding the serious side effects of clozapine some of which are associated with fatalities and presents a comprehensive way to monitor patients on clozapine in clinical practice. It emphasizes the need to broaden the monitoring beyond the mandatory investigations. This may help in improving the safety in clinical practice and increasing clinician confidence for greater and appropriate use of this effective intervention.
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Affiliation(s)
- Nilamadhab Kar
- Black Country Partnership NHS Foundation Trust, Wolverhampton, United Kingdom
| | - Socorro Barreto
- Black Country Partnership NHS Foundation Trust, Wolverhampton, United Kingdom
| | - Rahul Chandavarkar
- North Staffordshire Combined Healthcare NHS Trust, Stoke-on-Trent, United Kingdom
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Lally J, Gaughran F, Timms P, Curran SR. Treatment-resistant schizophrenia: current insights on the pharmacogenomics of antipsychotics. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2016; 9:117-129. [PMID: 27853387 PMCID: PMC5106233 DOI: 10.2147/pgpm.s115741] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Up to 30% of people with schizophrenia do not respond to two (or more) trials of dopaminergic antipsychotics. They are said to have treatment-resistant schizophrenia (TRS). Clozapine is still the only effective treatment for TRS, although it is underused in clinical practice. Initial use is delayed, it can be hard for patients to tolerate, and clinicians can be uncertain as to when to use it. What if, at the start of treatment, we could identify those patients likely to respond to clozapine – and those likely to suffer adverse effects? It is likely that clinicians would feel less inhibited about using it, allowing clozapine to be used earlier and more appropriately. Genetic testing holds out the tantalizing possibility of being able to do just this, and hence the vital importance of pharmacogenomic studies. These can potentially identify genetic markers for both tolerance of and vulnerability to clozapine. We aim to summarize progress so far, possible clinical applications, limitations to the evidence, and problems in applying these findings to the management of TRS. Pharmacogenomic studies of clozapine response and tolerability have produced conflicting results. These are due, at least in part, to significant differences in the patient groups studied. The use of clinical pharmacogenomic testing – to personalize clozapine treatment and identify patients at high risk of treatment failure or of adverse events – has moved closer over the last 20 years. However, to develop such testing that could be used clinically will require larger, multicenter, prospective studies.
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Affiliation(s)
- John Lally
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland; National Psychosis Service
| | - Fiona Gaughran
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; National Psychosis Service
| | - Philip Timms
- START Team, South London and Maudsley NHS Foundation Trust; King's College London
| | - Sarah R Curran
- King's College London; South West London and St George's Mental Health NHS Foundation Trust; St George's University of London, London, UK
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Abstract
Second-generation antidepressants are more selective in their pharmacological mechanisms and offer fewer side effects and a safer toxicological profile than cyclic antidepressants and monoamine oxidase inhibitors. While the risk for pharmacodynamic interactions is more limited than with older agents with broader receptor effects, the risks for pharmacokinetic interactions is greater. The capacity of selective serotonin reuptake inhibitors to inhibit the metabolic activity of cytochrome P450 isozyme system has spurred over a decade of intense psychopharmacological and pharmacogenetics research to better the understanding of the significance of these interactions. Clinicians have had to increase their knowledge and understanding of drug interaction potential to better manage patients receiving these newer antidepressants. The following is a review of both pharmacodynamic and pharmacokinetic drug-drug interactions with antidepressants.
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Affiliation(s)
- Sheila R. Botts
- University of Kentucky College of Pharmacy, UK Mental Health Research Center, 627 West 4th Street, Lexington, KY 40508
| | - Cara Alfaro
- National Institute of Mental Health, NIH Clinical Center, Pharmacy, Bld 10, Rm 1N-257, 10 Center Drive, Bethesda, MD 20892
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Shirazi A, Stubbs B, Gomez L, Moore S, Gaughran F, Flanagan RJ, MacCabe JH, Lally J. Prevalence and Predictors of Clozapine-Associated Constipation: A Systematic Review and Meta-Analysis. Int J Mol Sci 2016; 17:E863. [PMID: 27271593 PMCID: PMC4926397 DOI: 10.3390/ijms17060863] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 05/13/2016] [Accepted: 05/16/2016] [Indexed: 01/11/2023] Open
Abstract
Constipation is a frequently overlooked side effect of clozapine treatment that can prove fatal. We conducted a systematic review and meta-analysis to estimate the prevalence and risk factors for clozapine-associated constipation. Two authors performed a systematic search of major electronic databases from January 1990 to March 2016 for articles reporting the prevalence of constipation in adults treated with clozapine. A random effects meta-analysis was conducted. A total of 32 studies were meta-analyzed, establishing a pooled prevalence of clozapine-associated constipation of 31.2% (95% CI: 25.6-37.4) (n = 2013). People taking clozapine were significantly more likely to be constipated versus other antipsychotics (OR 3.02 (CI: 1.91-4.77), p < 0.001, n = 11 studies). Meta-regression identified two significant study-level factors associated with constipation prevalence: significantly higher (p = 0.02) rates of constipation were observed for those treated in inpatient versus outpatient or mixed settings and for those studies in which constipation was a primary or secondary outcome measure (36.9%) compared to studies in which constipation was not a specified outcome measure (24.8%, p = 0.048). Clozapine-associated constipation is common and approximately three times more likely than with other antipsychotics. Screening and preventative strategies should be established and appropriate symptomatic treatment applied when required.
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Affiliation(s)
- Ayala Shirazi
- GKT School of Medical Education Department, King's College London University, London SE1 1UL, UK.
| | - Brendon Stubbs
- Health Service and Population Research Department, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
- Physiotherapy Department, South London and Maudsley NHS Foundation Trust, Denmark Hill, London SE5 8AZ, UK.
| | - Lucia Gomez
- GKT School of Medical Education Department, King's College London University, London SE1 1UL, UK.
| | - Susan Moore
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 8AF, UK.
| | - Fiona Gaughran
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 8AF, UK.
- National Psychosis Unit, South London and Maudsley NHS Foundation Trust, London BR3 3BX, UK.
| | - Robert J Flanagan
- Toxicology Unit, Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, Denmark Hill, London SE5 9RS, UK.
| | - James H MacCabe
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 8AF, UK.
- National Psychosis Unit, South London and Maudsley NHS Foundation Trust, London BR3 3BX, UK.
| | - John Lally
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 8AF, UK.
- National Psychosis Unit, South London and Maudsley NHS Foundation Trust, London BR3 3BX, UK.
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The clinical potentials of adjunctive fluvoxamine to clozapine treatment: a systematic review. Psychopharmacology (Berl) 2016; 233:741-50. [PMID: 26626327 DOI: 10.1007/s00213-015-4161-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/24/2015] [Indexed: 10/22/2022]
Abstract
RATIONALE New clozapine optimization strategies are warranted, as some patients do not achieve sufficient response and experience various adverse effects. Fluvoxamine is a potent CYP1A2 inhibitor and may increase the ratio of clozapine to its primary metabolite N-desmethylclozapine (NDMC). OBJECTIVES This study aims to review all pharmacodynamic effects and the adverse effect profile of changing the clozapine/NDMC ratio with adjunctive fluvoxamine. METHODS MEDLINE, Embase, and the Cochrane Library were searched with the search terms "clozapine" and "fluvoxamine" without any time limit. Language was restricted to English, Scandinavian, Polish, and German. Studies were sorted for relevance based on title and abstract. Clinical recommendations of potential indications/effects were graded as level A, B, C, or D depending on studies of high, moderate, low, or very low quality, respectively. RESULTS Based on data from 24 case reports/series, seven cohort studies, and two randomized controlled trials, 241 patients were studied. Evidence (A) supported that adjunctive fluvoxamine increased clozapine plasma levels. This may increase the probability of response in patients, where sufficient clozapine plasma levels cannot be achieved. Adjunctive fluvoxamine reduced metabolic adverse effects of clozapine (B) but not agranulocytosis risk (B). Although depressive or obsessive-compulsive symptoms may improve, a SSRI with no CYP1A2 inhibition should rather be used (C). No studies investigated the effect of adjunctive fluvoxamine to minimize clozapine rebound psychosis (D) or to reduce the effects of smoking on clozapine plasma levels (D). CONCLUSIONS Adjunctive fluvoxamine may have clinical potentials for optimizing clozapine treatment but further clinical studies are warranted to explore the clinical implications.
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Effect of proton pump inhibitors on the serum concentrations of the selective serotonin reuptake inhibitors citalopram, escitalopram, and sertraline. Ther Drug Monit 2015; 37:90-7. [PMID: 24887634 PMCID: PMC4297217 DOI: 10.1097/ftd.0000000000000101] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Background: The selective serotonin reuptake inhibitors (SSRIs) citalopram, escitalopram, and sertraline are all metabolized by the cytochrome P-450 isoenzyme CYP2C19, which is inhibited by the proton pump inhibitors (PPIs) omeprazole, esomeprazole, lansoprazole, and pantoprazole. The aim of the present study was to evaluate the effect of these PPIs on the serum concentrations of citalopram, escitalopram, and sertraline. Methods: Serum concentrations from patients treated with citalopram, escitalopram, or sertraline were obtained from a routine therapeutic drug monitoring database, and samples from subjects concomitantly using PPIs were identified. Dose-adjusted SSRI serum concentrations were calculated to compare data from those treated and those not treated with PPIs. Results: Citalopram concentrations were significantly higher in patients treated with omeprazole (+35.3%; P < 0.001), esomeprazole (+32.8%; P < 0.001), and lansoprazole (+14.7%; P = 0.043). Escitalopram concentrations were significantly higher in patients treated with omeprazole (+93.9%; P < 0.001), esomeprazole (+81.8%; P < 0.001), lansoprazole (+20.1%; P = 0.008), and pantoprazole (+21.6%; P = 0.002). Sertraline concentrations were significantly higher in patients treated with esomeprazole (+38.5%; P = 0.0014). Conclusions: The effect of comedication with PPIs on the serum concentration of SSRIs is more pronounced for omeprazole and esomeprazole than for lansoprazole and pantoprazole, and escitalopram is affected to a greater extent than are citalopram and sertraline. When omeprazole or esomeprazole are used in combination with escitalopram, a 50% dose reduction of the latter should be considered.
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Ellison JC, Dufresne RL. A review of the clinical utility of serum clozapine and norclozapine levels. Ment Health Clin 2015. [DOI: 10.9740/mhc.2015.03.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Treatment refractory schizophrenia is a serious issue affecting at least 30% of all patients with schizophrenia despite the continued emergence of new agents aimed at treating this disease. Clozapine therapy remains the most efficacious treatment for patients with schizophrenia who have failed two prior antipsychotics or those deemed an imminent harm to themselves or others. Because data are lacking on how to proceed if a patient should prove nonresponsive to clozapine therapy, the utmost care should be taken to ensure the optimization of clozapine. Therapeutic drug monitoring (TDM) is used with many other psychoactive agents to ensure the optimal therapeutic efficacy while minimizing adverse effects. The unique pharmacology of clozapine and the inter- and intraindividual variations in its pharmacokinetics make it a difficult agent with which to use TDM. The consensus is that 350 ng/mL is the lower threshold of therapeutic efficacy to define an adequate trial of clozapine. As of this writing, no clearly defined threshold exists for the upper limit of therapeutic efficacy or toxicity. TDM of clozapine can be useful in the following circumstances: when a clozapine-induced central nervous system toxicity is suspected, a medication that can inhibit or induce the metabolism of clozapine is being added or withdrawn, a change in smoking status has occurred, concerns for medication nonadherence are present, or decompensation while on a previously effective clozapine dosage is observed. The psychiatric pharmacist may play a crucial role in the interpretation and effective utilization of serum clozapine and norclozapine levels. This review will examine the current evidence for the clinical utility of monitoring serum levels of clozapine and its metabolites.
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Retrospective evaluation of therapeutic drug monitoring of clozapine and norclozapine in Belgium using a multidrug UHPLC–MS/MS method. Clin Biochem 2014; 47:336-9. [DOI: 10.1016/j.clinbiochem.2014.09.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/17/2014] [Accepted: 09/26/2014] [Indexed: 11/20/2022]
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Muscatello MRA, Bruno A, De Fazio P, Segura-Garcia C, Pandolfo G, Zoccali R. Augmentation strategies in partial responder and/or treatment-resistant schizophrenia patients treated with clozapine. Expert Opin Pharmacother 2014; 15:2329-45. [PMID: 25284216 DOI: 10.1517/14656566.2014.956082] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Although clozapine (CLZ) is considered the best evidence-based therapeutic option for treatment of resistant schizophrenia patients, a significant proportion of CLZ-treated patients show a partial or inadequate response to treatment, leading to increased healthcare cost and poor quality of life for affected individuals. AREAS COVERED This paper comprises a review of main research in CLZ augmentation strategies for treatment-refractory schizophrenia, with a focus on research conducted between 1990 and 2014. Databases that were searched include: PubMed, CINAHL, EMBASE PsychINFO, AgeLine and Cochrane Database of Systematic Reviews. Primary search terms were 'clozapine augmentation', 'clozapine and add-on' and 'treatment-resistant schizophrenia', with cross reference to specific agents covered in this article. We reviewed the available evidence on CLZ augmentation with antipsychotics, antidepressants, mood stabilizers and other agents. EXPERT OPINION Many drugs have been evaluated as CLZ add-on therapies without demonstrating convincing efficacy in treating refractory schizophrenia symptoms. More research is needed to better define outcomes in schizophrenia, the topic of treatment-resistance and more well-designed trials are required to establish true efficacy and safety of CLZ augmentation strategies.
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Affiliation(s)
- Maria Rosaria A Muscatello
- University of Messina, Department of Neurosciences , Policlinico Universitario Via Consolare Valeria - Messina 98125 , Italy +39 090 22212092 ; +39 090 695136 ;
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Spina E, de Leon J. Clinically relevant interactions between newer antidepressants and second-generation antipsychotics. Expert Opin Drug Metab Toxicol 2014; 10:721-46. [PMID: 24494611 DOI: 10.1517/17425255.2014.885504] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Combinations of newer antidepressants and second-generation antipsychotics (SGAs) are frequently used by clinicians. Pharmacokinetic drug interaction (PK DI) and poorly understood pharmacodynamic (PD) drug interaction (PD DI) can occur between them. AREAS COVERED This paper comprehensively reviews PD DI and PK DI studies. EXPERT OPINION More PK DI studies are needed to better establish dose correction factors after adding fluoxetine and paroxetine to aripiprazole, iloperidone and risperidone. Further PK DI studies and case reports are also needed to better establish the need for dose correction factors after adding i) fluoxetine to clozapine, lurasidone, quetiapine and olanzapine; ii) paroxetine to olanzapine; iii) fluvoxamine to asenapine, aripiprazole, iloperidone, lurasidone, olanzapine, quetiapine and risperidone; iv) high sertraline doses to aripiprazole, clozapine, iloperidone and risperidone: v) bupropion and duloxetine to aripiprazole, clozapine, iloperidone and risperidone; and vi) asenapine to paroxetine and venlafaxine. Possible beneficial PD DI effects occur after adding SGAs to newer antidepressants for treatment-resistant major depressive and obsessive-compulsive disorders. The lack of studies combining newer antidepressants and SGAs in psychotic depression is worrisome. PD DIs between newer antidepressants and SGAs may be more likely for mirtazapine and bupropion. Adding selective serotonin reuptake inhibitors and SGAs may increase QTc interval and may very rarely contribute to torsades de pointes.
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Affiliation(s)
- Edoardo Spina
- University of Messina, Policlinico Universitario, Department of Clinical and Experimental Medicine , Via Consolare Valeria, 98125 Messina , Italy +39 090 2213647 ; +39 090 2213300 ;
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Abstract
Atypical antipsychotics [also known as second-generation antipsychotics (SGAs)] have become a mainstay therapeutic treatment intervention for patients with schizophrenia, bipolar disorders and other psychotic conditions. These agents are commonly used with other medications--most notably, antidepressants and antiepileptic drugs. Drug interactions can take place by various pharmacokinetic, pharmacodynamic and pharmaceutical mechanisms. The pharmacokinetic profile of each SGA, especially with phase I and phase II metabolism, can allow for potentially significant drug interactions. Pharmacodynamic interactions arise when agents have comparable receptor site activity, which can lead to additive or competitive effects without alterations in measured plasma drug concentrations. Additionally, the role of drug transporters in drug interactions continues to evolve and may effect both pharmacokinetic and pharmacodynamic interactions. Pharmaceutical interactions occur when physical incompatibilities take place between agents prior to drug absorption. Approximate therapeutic plasma concentration ranges have been suggested for a number of SGAs. Drug interactions that markedly increase or decrease the concentrations of these agents beyond their ranges can lead to adverse events or diminished clinical efficacy. Most clinically significant drug interactions with SGAs occur via the cytochrome P450 (CYP) system. Many but not all drug interactions with SGAs are identified during drug discovery and pre-clinical development by employing a series of standardized in vitro and in vivo studies with known CYP inducers and inhibitors. Later therapeutic drug monitoring programmes, clinical studies and case reports offer methods to identify additional clinically significant drug interactions. Some commonly co-administered drugs with a significant potential for drug-drug interactions with selected SGAs include some SSRIs. Antiepileptic mood stabilizers such as carbamazepine and valproate, as well as other antiepileptic drugs such as phenobarbital and phenytoin, may decrease plasma SGA concentrations. Some anti-infective agents such as protease inhibitors and fluoroquinolones are of concern as well. Two additional important factors that influence drug interactions with SGAs are dose and time dependence. Smoking is very common among psychiatric patients and can induce CYP1A2 enzymes, thereby lowering expected plasma levels of certain SGAs. It is recommended that ziprasidone and lurasidone are taken with food to promote drug absorption, otherwise their bioavailability can be reduced. Clinicians must be aware of the variety of factors that can increase the likelihood of clinically significant drug interactions with SGAs, and must carefully monitor patients to maximize treatment efficacy while minimizing adverse events.
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Affiliation(s)
- William Klugh Kennedy
- Department of Pharmacy Practice, Mercer University College of Pharmacy and Health Sciences, Atlanta, GA, 76107, USA
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Yeh ML, Chang YJ, Wang PY, Li YCJ, Hsu CY. Physicians' responses to computerized drug-drug interaction alerts for outpatients. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2013; 111:17-25. [PMID: 23608682 DOI: 10.1016/j.cmpb.2013.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 01/30/2013] [Accepted: 02/20/2013] [Indexed: 06/02/2023]
Abstract
INTRODUCTION Adverse drug reactions (ADR) increase morbidity and mortality; potential drug-drug interactions (DDI) increase the probability of ADR. Studies have proven that computerized drug-interaction alert systems (DIAS) might reduce medication errors and potential adverse events. However, the relatively high override rates obscure the benefits of alert systems, which result in barriers for availability. It is important to understand the frequency at which physicians override DIAS and the reasons for overriding reminders. METHOD All the DDI records of outpatient prescriptions from a tertiary university hospital from 2005 and 2006 detections by the DIAS are included in the study. The DIAS is a JAVA language software that was integrated into the computerized physician order entry system. The alert window is displayed when DDIs occur during order entries, and physicians choose the appropriate action according to the DDI alerts. There are seven response choices are obligated in representing overriding and acceptance: (1) necessary order and override; (2) expected DDI and override; (3) expected DDI with modified dosage and override; (4) no DDI and override; (5) too busy to respond and override; (6) unaware of the DDI and accept; and (7) unexpected DDI and accept. The responses were collected for analysis. RESULTS A total of 11,084 DDI alerts of 1,243,464 outpatient prescriptions were present, 0.89% of all computerized prescriptions. The overall rate for accepting was 8.5%, but most of the alerts were overridden (91.5%). Physicians of family medicine and gynecology-obstetrics were more willing to accept the alerts with acceptance rates of 20.8% and 20.0% respectively (p<0.001). Information regarding the recognition of DDIs indicated that 82.0% of the DDIs were aware by physicians, 15.9% of DDIs were unaware by physicians, and 2.1% of alerts were ignored. The percentage of total alerts declined from 1.12% to 0.79% during 24 months' study period, and total overridden alerts also declined (from 1.04% to 0.73%). CONCLUSION We explored the physicians' behavior by analyzing responses to the DDI alerts. Although the override rate is still high, the reasons why physicians may override DDI alerts were well analyzed and most DDI were recognized by physicians. Nonetheless, the trend of total overrides is in decline, which indicates a learning curve effect from exposure to DIAS. By analyzing the computerized responses provided by physicians, efforts should be made to improve the efficiency of the DIAS, and pharmacists, as well as patient safety staffs, can catch physicians' appropriate reasons for overriding DDI alerts, improving patient safety.
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Affiliation(s)
- Min-Li Yeh
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Increasing the clozapine: Norclozapine ratio with co-administration of fluvoxamine to enhance efficacy and minimize side effects of clozapine therapy. Med Hypotheses 2013; 80:689-91. [DOI: 10.1016/j.mehy.2012.12.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 12/10/2012] [Accepted: 12/23/2012] [Indexed: 01/11/2023]
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Wang CY, Zhang ZJ, Li WB, Zhai YM, Cai ZJ, Weng YZ, Zhu RH, Zhao JP, Zhou HH. The Differential Effects of Steady-State Fluvoxamine on the Pharmacokinetics of Olanzapine and Clozapine in Healthy Volunteers. J Clin Pharmacol 2013; 44:785-92. [PMID: 15199083 DOI: 10.1177/0091270004266621] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The combination of atypical antipsychotics and selective serotonin reuptake inhibitors is an effective strategy in the treatment of certain psychiatric disorders. However, pharmacokinetic interactions between the two classes of drugs remain to be explored. The present study was designed to determine whether there were different effects of steady-state fluvoxamine on the pharmacokinetics of a single dose of olanzapine and clozapine in healthy male volunteers. One single dose of 10 mg olanzapine (n = 12) or clozapine (n = 9) was administered orally. Following a drug washout of at least 4 weeks, all subjects received fluvoxamine (100 mg/day) for 9 days, and one single dose of 10 mg olanzapine or clozapine was added on day 4. Plasma concentrations of olanzapine, clozapine, and N-desmethylclozapine were assayed at serial time points after the antipsychotics were given alone and when added to fluvoxamine. No bioequivalence was found in olanzapine alone and cotreatment with fluvoxamine for the mean peak plasma concentration (C(max)), the area under the concentration-time curve from time 0 to last sampling time point (AUC(0-t)), and from time 0 to infinity (AUC(0- infinity )). Under the cotreatment, C(max) of olanzapine was significantly elevated by 49%, with a 32% reduced time (t(max)) to C(max), whereas the C(max) and t(max) of clozapine were unaltered. The cotreatment increased the AUC(0-t) and AUC(0- infinity ) of olanzapine by 68% and 76%, respectively, greater than those of clozapine (40% and 41%). The presence of fluvoxamine also prolonged the elimination half-life (t(1/2)) of olanzapine by 40% and, to a much greater extent, clozapine by 370% but reduced the total body clearance (CL/F) of clozapine (78%) more significantly than it did for olanzapine (42%). The apparent volume of distribution (V(d)) was suppressed by 31% in olanzapine combined with fluvoxamine but was unaltered in the clozapine regimen. A significant reduction in the N-desmethylclozapine to clozapine ratio was present in the clozapine with fluvoxamine regimen. The effects of fluvoxamine on different aspects of pharmacokinetics of the two antipsychotics may have implications for clinical therapeutics.
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Affiliation(s)
- Chuan-Yue Wang
- Laboratory of Clinical Psychopharmacology, Beijing An Ding Hospital, Capital University of Medical Sciences, 5 Ankang Hutong Road, Xicheng District, Beijing 100088, China
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Chang SC, Lu ML. Metabolic and Cardiovascular Adverse Effects Associated with Treatment with Antipsychotic Drugs. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.jecm.2012.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Danovich L, Weinreb O, Youdim MBH, Silver H. Chronic treatment with serotonin reuptake inhibitor antidepressant (SSRI) combined with an antipsychotic regulates GABA-A receptor in rat prefrontal cortex. Psychopharmacology (Berl) 2012; 220:763-70. [PMID: 21989809 DOI: 10.1007/s00213-011-2530-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/26/2011] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The combination of selective serotonin reuptake inhibitor (SSRI) antidepressants and antipsychotics is currently used for the treatment of negative symptoms of schizophrenia. However, the biochemical mechanism mediating the clinical effectiveness of this treatment remains obscure. Previously, we have reported that acute haloperidol (HALO)-fluvoxamine (FLU) in vivo and in vitro treatment regulated GABA-Aβ2/3 receptor subunits, and protein kinase C (PKC) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathways. FINDINGS In the present study, we demonstrated that chronic HALO-FLU treatment, but not each drug alone, significantly decreased GABA-Aβ2/3 receptor expression (25 ± 6.2% vs. control) and caused receptor translocation from the membrane to the cytosol in rat prefrontal cortex. Phosphorylation of PKC and ERK2 was affected differently by HALO-FLU combination than by the individual drug treatments. HALO and FLU each given alone increased PKC phosphorylation levels (29 ± 15% and 40 ± 11.8%, vs. control, respectively) and did not affect ERK2 phosphorylation, while HALO-FLU combined treatment did not alter PKC phosphorylation levels and significantly decreased ERK2 phosphorylation levels (58 ± 4.4% vs. control). GABA-A receptor downregulation in the brain was accompanied by a decrease in GABA-A function, as shown in muscimol-induced loss of righting reflex (22 ± 9.8 min). CONCLUSIONS We provide a brief heuristic overview of our preclinical and clinical studies with the SSRI-antipsychotic combination and argue that the finding that it causes similar dynamic changes in laboratory and clinical domains, specifically in GABA-A β2/3 receptor and PKC, strongly supports the hypothesis that the GABA-A receptors and their regulatory systems are involved in the molecular mechanisms underlying the clinical effectiveness of SSRI augmentation.
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Affiliation(s)
- Lena Danovich
- Molecular Neuropsychiatry Unit, Shaar Menashe Brain Behavior Laboratory, Shaar Menashe MHC and Technion-Faculty of Medicine, Mobile Post, 38814, Haifa, Israel
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Porcelli S, Balzarro B, Serretti A. Clozapine resistance: augmentation strategies. Eur Neuropsychopharmacol 2012; 22:165-82. [PMID: 21906915 DOI: 10.1016/j.euroneuro.2011.08.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 08/12/2011] [Accepted: 08/13/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Clozapine (CLZ) is not effective in more than 50% of treatment-resistant schizophrenic patients. In these cases, several pharmacological strategies are used in clinical practice, with different levels of evidence for both safety and efficacy. OBJECTIVES In the present paper we critically reviewed literature data regarding the efficacy and safety of adjunctive agents in CLZ-resistant schizophrenics. The following classes of agents were considered: 1) antipsychotics, 2) antidepressants, 3) mood stabilizers, 4) other agents (e.g. fatty acid supplement and glutamatergic agents), 5) electroconvulsive therapy (ECT). For lamotrigine and risperidone sufficient data were available to perform a meta-analysis. METHODS A Medline literature search covering a 20-year period was performed. For the meta-analysis, data were entered and analyzed with the Cochrane Collaboration Review Manager Software (RevMan version 5). RESULTS 62 pertinent studies were identified, including 1556 schizophrenic or schizoaffective patients. Among treatments investigated, there is evidence for CLZ augmentation with 1) amisulpride and aripiprazole, 2) mirtazapine and 3) ethyl eicosapentaenoic acid (E-EPA). Although promising, ECT augmentation needs further validation. The meta-analyses did not support either the use of risperidone or lamotrigine as CLZ adjunct. CONCLUSION Overall, there is scarce evidence of efficacy and safety as regards adjunctive strategies for CLZ-resistant patients. However, several limitations do not allow to draw any definitive conclusion; among these we underline the small sample size of clinical trials, the variable definitions of CLZ resistance, the heterogeneity of outcome measures and methodological designs.
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Affiliation(s)
- Stefano Porcelli
- Institute of Psychiatry, University of Bologna, Viale Carlo Pepoli 5, 40123 Bologna, Italy
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Abstract
As a consequence of individualized antipsychotic pharmacotherapy, many patients need more than a single drug, since they do not respond sufficiently to monotherapy. Other patients suffer from comorbid diseases and therefore require additional drugs from other pharmacological classes. Drug combinations, however, can give rise to pharmacokinetic and/or pharmacodynamic drug-drug interactions. Evaluation of pharmacokinetic interactions with antipsychotic drugs must consider substrate, inhibitor, and inducer properties for the cytochrome P450 (CYP) isoenzymes of all combined drugs. For consideration of pharmacodynamic interactions, special attention must be given to effects on dopamine D(2), histamine H(1), and acetylcholine M(1) receptors and on cardiac potassium channels. Additive pharmacological actions of combined drugs on these target structures can induce adverse reactions such as extrapyramidal symptoms, drowsiness, metabolic disturbances leading to weight gain and cardiac problems, cognitive impairment, delirium, or ventricular arrhythmia. Measuring plasma concentrations, i.e., therapeutic drug monitoring (TDM), is valuable to adjust antipsychotic medication when drug combinations contain inhibitors or inducers that alter plasma concentrations of the antipsychotic drugs. Amalgamating the broad knowledge on drug-drug interactions and using appropriately the option to monitor plasma concentrations in blood will help to apply complex combination therapies with antipsychotic drugs with maximal efficiency and safety.
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Affiliation(s)
- Christoph Hiemke
- Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany.
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Clinical impact of fluvoxamine-mediated long QTU syndrome. Eur J Clin Pharmacol 2011; 68:109-11. [DOI: 10.1007/s00228-011-1091-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
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Wohlfarth A, Toepfner N, Hermanns-Clausen M, Auwärter V. Sensitive quantification of clozapine and its main metabolites norclozapine and clozapine-N-oxide in serum and urine using LC-MS/MS after simple liquid–liquid extraction work-up. Anal Bioanal Chem 2011; 400:737-46. [DOI: 10.1007/s00216-011-4831-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/19/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
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Zhou SF, Wang B, Yang LP, Liu JP. Structure, function, regulation and polymorphism and the clinical significance of human cytochrome P450 1A2. Drug Metab Rev 2010; 42:268-354. [PMID: 19961320 DOI: 10.3109/03602530903286476] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Human CYP1A2 is one of the major CYPs in human liver and metabolizes a number of clinical drugs (e.g., clozapine, tacrine, tizanidine, and theophylline; n > 110), a number of procarcinogens (e.g., benzo[a]pyrene and aromatic amines), and several important endogenous compounds (e.g., steroids). CYP1A2 is subject to reversible and/or irreversible inhibition by a number of drugs, natural substances, and other compounds. The CYP1A gene cluster has been mapped on to chromosome 15q24.1, with close link between CYP1A1 and 1A2 sharing a common 5'-flanking region. The human CYP1A2 gene spans almost 7.8 kb comprising seven exons and six introns and codes a 515-residue protein with a molecular mass of 58,294 Da. The recently resolved CYP1A2 structure has a relatively compact, planar active site cavity that is highly adapted for the size and shape of its substrates. The architecture of the active site of 1A2 is characterized by multiple residues on helices F and I that constitutes two parallel substrate binding platforms on either side of the cavity. A large interindividual variability in the expression and activity of CYP1A2 has been observed, which is largely caused by genetic, epigenetic and environmental factors (e.g., smoking). CYP1A2 is primarily regulated by the aromatic hydrocarbon receptor (AhR) and CYP1A2 is induced through AhR-mediated transactivation following ligand binding and nuclear translocation. Induction or inhibition of CYP1A2 may provide partial explanation for some clinical drug interactions. To date, more than 15 variant alleles and a series of subvariants of the CYP1A2 gene have been identified and some of them have been associated with altered drug clearance and response and disease susceptibility. Further studies are warranted to explore the clinical and toxicological significance of altered CYP1A2 expression and activity caused by genetic, epigenetic, and environmental factors.
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Affiliation(s)
- Shu-Feng Zhou
- Discpline of Chinese Medicine, School of Health Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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Murray M. Role of CYP pharmacogenetics and drug-drug interactions in the efficacy and safety of atypical and other antipsychotic agents. J Pharm Pharmacol 2010; 58:871-85. [PMID: 16805946 DOI: 10.1211/jpp.58.7.0001] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Abstract
Cytochrome P450 (CYP) drug oxidases play a pivotal role in the elimination of antipsychotic agents, and therefore influence the toxicity and efficacy of these drugs. Factors that affect CYP function and expression have a major impact on treatment outcomes with antipsychotic agents. In particular, aspects of CYP pharmacogenetics, and the processes of CYP induction and inhibition all influence in-vivo rates of drug elimination. Certain CYPs that mediate the oxidation of antipsychotic drugs exhibit genetic variants that may influence in-vivo activity. Thus, single nucleotide polymorphisms (SNPs) in CYP genes have been shown to encode enzymes that have decreased drug oxidation capacity. Additionally, psychopharmacotherapy has the potential for drug-drug inhibitory interactions involving CYPs, as well as drug-mediated CYP induction. Literature evidence supports a role for CYP1A2 in the clearance of the atypical antipsychotics clozapine and olanzapine; CYP1A2 is inducible by certain drugs and environmental chemicals. Recent studies have suggested that specific CYP1A2 variants possessing individual SNPs, and possibly also SNP combinations (haplotypes), in the 5′-regulatory regions may respond differently to inducing chemicals. CYP2D6 is an important catalyst of the oxidation of chlorpromazine, thioridazine, risperidone and haloperidol. Certain CYP2D6 allelic variants that encode enzymes with decreased drug oxidation capacity are more common in particular ethnic groups, which may lead to adverse effects with standard doses of psychoactive drugs. Thus, genotyping may be useful for dose optimization with certain psychoactive drugs that are substrates for CYP2D6. However, genotyping for inducible CYPs is unlikely to be sufficient to direct therapy with all antipsychotic agents. In-vivo CYP phenotyping with cocktails of drug substrates may assist at the commencement of therapy, but this approach could be complicated by pharmacokinetic interactions if applied when an antipsychotic drug regimen is ongoing.
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Affiliation(s)
- Michael Murray
- Pharmacogenomics and Drug Development Group, Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
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Inefficacité de la clozapine en rapport avec un métabolisme augmenté et intérêt de la fluvoxamine : à propos de quatre cas. Encephale 2007; 33:811-8. [DOI: 10.1016/j.encep.2007.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lin SK, Su SF, Pan CH. Higher Plasma Drug Concentration in Clozapine-treated Schizophrenic Patients With Side Effects of Obsessive/Compulsive Symptoms. Ther Drug Monit 2006; 28:303-7. [PMID: 16778711 DOI: 10.1097/01.ftd.0000211801.66569.80] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Clozapine-induced obsessive/compulsive symptoms (OCS) have been reported by many authors. This study investigated the incidence of these side effects, together with the relation between these side effects and the plasma concentration (Cps) of clozapine and its metabolites norclozapine and clozapine-N-oxide in schizophrenic patients. One hundred and two schizophrenic patients treated with clozapine were interviewed and screened with questionnaires testing for OCS during a 1-year study period. Cps of clozapine and the metabolites were monitored using reversed-phase high-performance liquid chromatography with ultraviolet detection. Thirty-nine patients (38.2%) presented with OCS, and, of these, 29 patients (28.4%) were classified as clozapine-induced, with an average latent period of 39.8+/-22.5 months. The Cps of clozapine and norclozapine were significantly higher in patients with OCS than in those without (595.1+/-364.9 vs. 433.5+/-252.8 ng/mL, P=0.001 and 266.4+/-144.4 vs. 203.1+/-119.8 ng/mL) OCS. Clozapine-induced OCS were not uncommon side effects. The authors suggest that the emergence of these side effects may be related to higher Cps of clozapine and clinicians should routinely check for and manage these side effects.
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Affiliation(s)
- Shih-Ku Lin
- Department of General Psychiatry and Laboratory of Biological Psychiatry, Taipei City Psychiatric Center, Taipei, Taiwan.
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Tranulis C, Mouaffak F, Chouchana L, Stip E, Gourevitch R, Poirier MF, Olié JP, Lôo H, Gourion D. Somatic augmentation strategies in clozapine resistance--what facts? Clin Neuropharmacol 2006; 29:34-44. [PMID: 16518133 DOI: 10.1097/00002826-200601000-00010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Polypharmacy without evidence-based support is sometimes needed for patients treated with 40% to 70% clozapine who are clozapine nonresponders. Several somatic augmentation strategies are proposed in the scientific literature, with different levels of evidence for safety and efficacy. OBJECTIVES The purpose of the present study is to review the available literature on the efficacy and safety of clozapine augmentation with somatic agents other than antipsychotics. The following classes of agents are considered: (1) mood stabilizers, (2) antidepressants, (3) electroconvulsive therapy and repetitive transcranial magnetic stimulation, (4) glutamatergic agents, (5)fatty acids supplements, and (6) benzodiazepines. RESULTS Case controls and small-size clinical trials largely dominate the literature, limiting the power to draw conclusions concerning safety issues and the meaning of negative studies. Moreover, variable definitions of clozapine resistance, heterogeneous outcome measures, and short duration of treatment trials are additional limitations. CONCLUSION Generally, adjunctive strategies for clozapine-resistant patients remain based on scarce evidence of efficacy and significant safety concerns. Low-frequency repetitive transcranial magnetic stimulation, fatty acids supplements, and mirtazapine showed good tolerability and some efficacy, but the results need replication.
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Wong JOY, Leung SP, Mak T, Ng RMK, Chan KT, Hon-Kee Cheung H, Choi WK, Lai J, Wai-Kiu Tsang A. Plasma clozapine levels and clinical response in treatment-refractory Chinese schizophrenic patients. Prog Neuropsychopharmacol Biol Psychiatry 2006; 30:251-64. [PMID: 16316716 DOI: 10.1016/j.pnpbp.2005.10.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate clinical efficacy of clozapine in relation with its plasma level in a group of Chinese patients with treatment-resistant schizophrenia. In addition, the relationship between plasma level and side effects were examined. METHOD Fifty-one patients with treatment-resistant schizophrenia were put on a fixed dose of clozapine at 300 mg/day for 6 weeks. Non-responders to week 6 received 500 mg/day in subsequent 6 weeks. Responders to week 6 continued to receive 300 mg/day. Clozapine plasma levels were checked at weeks 6 and 12. FINDINGS No association was found between clozapine plasma level, response and side effects. Sodium valproate was found to elevate clozapine plasma level while lowering norclozapine/clozapine ratio. CONCLUSION Clozapine plasma level was not found to be associated with response and side effect in Chinese treatment-resistant schizophrenic patients. Various explanations were postulated for the lack of relationship observed between clozapine plasma level and response in this population.
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Affiliation(s)
- Jessica Oi-Yin Wong
- Castle Peak Hospital, 15 Tsing Chung Koon Road, Tuen Mun, New Territories, Hong Kong, PR China.
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Ago Y, Sato M, Nakamura S, Baba A, Matsuda T. Lack of Enhanced Effect of Antipsychotics Combined With Fluvoxamine on Acetylcholine Release in Rat Prefrontal Cortex. J Pharmacol Sci 2006; 102:419-22. [PMID: 17130670 DOI: 10.1254/jphs.sc0060187] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
We have shown that coadministration of sulpiride and fluvoxamine preferentially increases the release of dopamine in the prefrontal cortex. To study the possible role of the cortical cholinergic system in this effect, we combined several other antipsychotic drugs with fluvoxamine and examined the effects on acetylcholine release in rat prefrontal cortex. Risperidone and clozapine significantly increased the release of acetylcholine but sulpiride did not, and fluvoxamine did not enhance the effects of the antipsychotics. These results further support the previous suggestion that the cortical dopamine system plays an important role in the effects of antipsychotic drugs administered in combination with fluvoxamine.
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Affiliation(s)
- Yukio Ago
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
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