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Cao Y, Xia Q, Liang J, Wang J, Shan F, Dai B. Effect of Common Cold on Serum Clozapine Concentrations in Hospitalized Patients with Schizophrenia. Neuropsychiatr Dis Treat 2024; 20:1563-1570. [PMID: 39156033 PMCID: PMC11330252 DOI: 10.2147/ndt.s473973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 08/06/2024] [Indexed: 08/20/2024] Open
Abstract
Objective The present study aims to investigate the effect of common cold on the serum clozapine concentrations in hospitalized patients with schizophrenia. Methods A total of 65 schizophrenic patients with common cold receiving clozapine treatment were retrospectively enrolled. The demographic data, medication situation, clozapine concentration, and parameters of routine haematological and biochemical laboratory tests were obtained from the medical record system. The serum clozapine concentration and clozapine concentration/dose (C/D) ratios between the baseline period and cold period were compared by paired-sample t tests. Association between the changes in serum concentration and C/D ratios of clozapine and changes in white blood cell (WBC) and neutrophil (NE) counts was evaluated using Pearson correlation analysis. Results The serum clozapine concentration (t = -9.856, P < 0.001) and clozapine C/D ratios (t = -10.071, P < 0.001) were found to be significantly elevated in the cold period compared to the baseline period. Moreover, the changes in the serum clozapine concentration were found to be significantly elevated in female patients compared to male patients (t = -2.483, P = 0.017). Furthermore, changes in the serum clozapine concentration were positively correlated to the changes in WBC (r = 0.303, P = 0.014) and NE (r = 0.315, P = 0.011) counts. Similarly, changes in clozapine C/D ratios were positively correlated to the changes in WBC (r = 0.275, P = 0.027) and NE (r = 0.328, P = 0.008) counts. Conclusion The serum clozapine concentrations in patients with schizophrenia during the common cold period were increased, which might by related to the elevated WBC and NE counts.
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Affiliation(s)
- Yin Cao
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
| | - Qingrong Xia
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
| | - Jun Liang
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
| | - Jiequan Wang
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
| | - Feng Shan
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
| | - Biao Dai
- Department of Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Department of Pharmacy, Hefei Fourth People’s Hospital, Hefei, People’s Republic of China
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, People’s Republic of China
- Department of Clinical Pharmacy, Anhui Clinical Research Center for Mental Disorders, Hefei, People’s Republic of China
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Mach A, Wnorowska A, Siwek M, Wojnar M, Radziwoń-Zaleska M. Clinical and pharmacological factors influencing serum clozapine and norclozapine levels. Front Pharmacol 2024; 15:1356813. [PMID: 38601469 PMCID: PMC11004283 DOI: 10.3389/fphar.2024.1356813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/15/2024] [Indexed: 04/12/2024] Open
Abstract
Background Clozapine (CLO) is a very effective antipsychotic, whose use is associated with dose-dependent risk of complications. Due to high interindividual variability in CLO metabolism, there is a need to identify factors affecting the blood concentrations of CLO and its active metabolite, norclozapine (NCLO). Methods A total of 446 blood samples (collected from 233 women and 213 men, aged from 18 to 77 years) were included in this study and analyzed for CLO and NCLO concentrations. The patients were treated at a psychiatric hospital in Warsaw in the years 2016-2021. Serum CLO and NCLO concentrations were determined with high-performance liquid chromatography coupled to UV. Results The following factors were shown to increase serum CLO and NCLO levels: higher CLO dose (p < 0.001), female sex (p < 0.001), nonsmoker status (p < 0.001), the use of more than two additional psychotropic drugs (only in the case of CLO; p = 0.046), concomitant use of beta-blockers (for CLO p = 0.049; for NCLO p < 0.001), and older age (for CLO p < 0.001; for NCLO p = 0.011). Despite the use of CLO at daily doses within the recommended range (200-450 mg), the evaluated serum CLO and NCLO levels were within the therapeutic ranges in only 37% and 75% of cases, respectively, with 5.6% of cases exceeding the CLO toxicity threshold. Discussion The use of CLO at recommended doses does not guarantee achieving therapeutic concentrations of CLO or NCLO. Women and nonsmokers were at the highest risk of having toxic CLO levels.
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Affiliation(s)
- Anna Mach
- Department of Psychiatry, Medical University of Warsaw, Warsaw, Poland
| | - Anna Wnorowska
- Department of Psychiatry, Medical University of Warsaw, Warsaw, Poland
| | - Marcin Siwek
- Department of Affective Disorders, Jagiellonian University Medical College, Cracow, Poland
| | - Marcin Wojnar
- Department of Psychiatry, Medical University of Warsaw, Warsaw, Poland
- Department of Psychiatry, Addiction Center, University of Michigan, Ann Arbor, MI, United States
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Xu JJ, Xiao C, Pan Y, Tang YL, Wang M, Li S, Xie G, Du J, Ren Y, Wang W. Utilizing plasma drug levels and genetic testing to achieve optimal treatment response in a patient with treatment-resistant schizoaffective disorder. Bipolar Disord 2024; 26:95-97. [PMID: 38097824 DOI: 10.1111/bdi.13385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
We report the case of a Chinese male with schizoaffective disorder, an active smoker and a nonresponder to clozapine (600 mg daily). Therapeutic clozapine monitoring was analyzed, revealing a low concentration-dose ratio. A pharmacogenetic test showed that the patient had the CYP1A2*1F/*1F genotype, indicating an ultra-rapid clozapine metabolizer. In combination with fluvoxamine, a CYP1A2 enzyme inhibitor, clozapine plasma concentrations approached the reference range and achieved clinical improvement. This case demonstrates how pharmacogenetics can help understand the value of therapeutic drug monitoring to enhance the treatment of refractory schizoaffective disorder.
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Affiliation(s)
- Jin-Jie Xu
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Chunfeng Xiao
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yanli Pan
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Yi-Lang Tang
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, USA
- Mental Health Service Line, Joseph Maxwell Cleland Atlanta VA Medical Center, Decatur, Georgia, USA
| | - Mingwan Wang
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Sheng Li
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Gaoming Xie
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Jing Du
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Yanping Ren
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Wei Wang
- Beijing Key Laboratory of Mental Disorders, National Clinical Research Center for Mental Disorders & National Center for Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
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Panić B, Jovanović M, Lukić V, Vučićević K, Miljković B, Milovanović S. Association of clozapine and norclozapine levels with patient and therapy characteristics-focus on interaction with valproic acid. Eur J Clin Pharmacol 2023; 79:1557-1564. [PMID: 37733278 DOI: 10.1007/s00228-023-03569-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/15/2023] [Indexed: 09/22/2023]
Abstract
PURPOSE The goal of the study was to examine clozapine (CLZ) and norclozapine (NCLZ) therapeutic drug monitoring (TDM) data and associated sources of pharmacokinetic variability, particularly the impact of valproic acid (VPA) use. METHODS This study included 126 patients with psychiatric disorders on mono- or co-therapy with CLZ. Patients' data during routine TDM were collected retrospectively from clinical records. The descriptive and statistical analysis was computed using IBM SPSS Statistics software (version 22, NY, USA). Multiple linear regression, based on the last observations, was used to assess correlation between demographic characteristics, life habits and co-therapy with dose-corrected serum levels (C/D) of CLZ and NCLZ, as well as CLZ/NCLZ. RESULTS A total of 295 CLZ concentrations were measured in 126 patients, with a mean of 275.5 ± 174.4 µg/L, while 124 NCLZ concentrations were determined in 74 patients, with a mean of 194.6 ± 149.8 µg/L. A statistically significant effect on ln-transformed CLZ C/D was confirmed for sex and smoking, whereas sex, smoking and VPA therapy were associated with ln-transformed NCLZ C/D. According to the final models, lower values of NCLZ C/D for about 45.9% can be expected in patients receiving VPA. Concomitant use of VPA was the only factor detected to contribute in CLZ/NCLZ variability. CONCLUSION The results of this study may help clinicians interpret TDM data and optimize CLZ dosing regimens, especially in patients concomitantly treated with VPA. Our results show that VPA primarily decreases NCLZ levels, while alteration of the parent drug is not statistically significant.
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Affiliation(s)
- Bojana Panić
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Marija Jovanović
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia.
| | - Vera Lukić
- Institute of Forensic Medicine "Milovan Milovanović", Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Vučićević
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Branislava Miljković
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Srđan Milovanović
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Psychiatry, University Clinical Center of Serbia, Belgrade, Serbia
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Demirbugen Oz M, Ozdemir F, Tok KC, Dural E, Kir Y, Ulusoy M, Gumustas M, Baskak B, Suzen HS. The potential role of por*28 and cyp1a2*f genetic variations and lifestyle factors on clozapine and n-desmethyl clozapine plasma levels in schizophrenia patients. Expert Opin Drug Metab Toxicol 2023. [PMID: 37269349 DOI: 10.1080/17425255.2023.2221849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023]
Abstract
BACKGROUND Despite its advantages over other antipsychotics, for treatment-resistant schizophrenia, clinical use of Clozapine (CLZ) is challenging by its narrow therapeutic index and potentially life-threatening dose-related adverse effects. RESEARCH DESIGN AND METHODS As the potential role in CLZ metabolism is assigned to CYP1A2 enzyme and consequently Cytochrome P450 oxidoreductase (POR) their genetic variations might help to determine CLZ levels in schizophrenia patients. For this purpose, 112 schizophrenia patients receiving CLZ were included in the current study. Plasma CLZ and N-desmethylclozapine (DCLZ) levels were analyzed by using HPLC and genetic variations were identified with the PCR-RFLP method. RESULTS The patients' CYP1A2 and POR genotypes seemed to not affect plasma CLZ and DCLZ levels whereas in the subgroup analysis, POR × 28 genotype significantly influenced simple and adjusted plasma CLZ and DLCZ levels concerning smoking habit and caffeine consumption. CONCLUSIONS The findings of the present study highlight the importance of both genetic and non-genetic factors (smoking and caffeine consumption) for the individualization of the CLZ treatment. In addition to that, it suggests that the added utility of not only the CLZ metabolizing enzymes but also POR, which is crucial for proper CYP activity, to guide CLZ dosing might be useful for clinical decision-making.
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Affiliation(s)
- Merve Demirbugen Oz
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
| | - Fezile Ozdemir
- Dr Fazil Kucuk Faculty of Medicine, Eastern Mediterranean University, North, Cyprus, Turkey
| | - Kenan Can Tok
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Emrah Dural
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Sivas Cumhuriyet University, Sivas, Turkey
| | - Yagmur Kir
- Bursa Acibadem Hospital, Department of Psychiatry, Bursa, Turkey
| | - Muge Ulusoy
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - Mehmet Gumustas
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Bora Baskak
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - H Sinan Suzen
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
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Qu K, Zhou Q, Zhu H, Zhou Z, Shen Y, Tian L, Su X. The Association Between Clozapine Plasma Concentration, CYP2D6 (*10, *2) Polymorphisms and Risk of Adverse Reactions. PSYCHIAT CLIN PSYCH 2023; 33:76-83. [PMID: 38765922 PMCID: PMC11082567 DOI: 10.5152/pcp.2023.22392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/27/2023] [Indexed: 05/22/2024] Open
Abstract
Background The aim of this article was to study the relationships between the risk of adverse reactions, plasma concentration, and cytochrome P450 2D6 rs1065852 (*10) and rs16947 (*2) polymorphisms for clozapine. Methods The steady-state clozapine plasma concentration of 100 Chinese inpatients with schizophrenia was determined using 2-dimensional liquid chromatography. The polymorphisms of cytochrome P450 2D6 (*10 and *2) were determined using fluorescent in situ hybridization protocols. Results The decreased percentages of white blood cells and neutrophils and the elevated percentages of creatine kinase, alanine aminotransferase, and aspartate transferase in patients treated with clozapine for 6 months were linearly associated with clozapine plasma concentration. Compared with the corresponding groups, the clozapine plasma concentrations of individuals with the *10TT genotype and individuals with the *2CC genotype were the highest (P < .05). The decreased percentages of white blood cells and neutrophils and elevated percentages of creatine kinase, alanine aminotransferase, and aspartate transferase for patients with the *10TT genotype were significantly higher than those for patients with the *10CC and *10CT genotypes (P < .05). The decreased percentages of white blood cells and neutrophils and increased percentages of creatine kinase, alanine aminotransferase, and aspartate transferase for patients with the *2CC genotype were significantly higher than those of the other groups (P < .05). The therapeutic reference range of clozapine for Chinese patients with schizophrenia was defined as 102.5-483.1 ng/mL. Conclusion This study demonstrated that the determination of cytochrome P450 2D6 polymorphisms and therapeutic drug monitoring of clozapine might be beneficial for identifying patients with a higher risk of adverse reactions.
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Affiliation(s)
- Kankan Qu
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Qin Zhou
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Haohao Zhu
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Zhenhe Zhou
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Yuan Shen
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Lin Tian
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
| | - Xujiang Su
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu, China
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Racial/Ethnic Differences in the Pharmacokinetics of Antipsychotics: Focusing on East Asians. J Pers Med 2022; 12:jpm12091362. [PMID: 36143147 PMCID: PMC9504618 DOI: 10.3390/jpm12091362] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Empirical clinical studies have suggested that East Asian patients may require lower dosages of psychotropic drugs, such as antipsychotics, lithium, and antidepressants, than non-Asians. Both the pharmacokinetic and pharmacodynamic properties of a drug can affect the clinical response of an illness. The levels of antipsychotics used for the treatment of schizophrenia may affect patient clinical responses; several factors can affect these levels, including patient medication adherence, body weight (BW) or body mass index, smoking habits, and sex. The cytochrome P450 (CYP) system is a major factor affecting the blood levels of antipsychotics because many antipsychotics are metabolized by this system. There were notable genetic differences between people of different races. In this study, we determined the racial or ethnic differences in the metabolic patterns of some selected antipsychotics by reviewing therapeutic drug monitoring studies in East Asian populations. The plasma concentrations of haloperidol, clozapine, quetiapine, aripiprazole, and lurasidone, which are metabolized by specific CYP enzymes, were determined to be higher, under the same daily dose, in East Asian populations than in Western populations.
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Plasma Clozapine and Norclozapine After Use of Either Crushed Tablets or Suspension Compared With Tablets. J Clin Psychopharmacol 2022; 42:400-404. [PMID: 35652731 DOI: 10.1097/jcp.0000000000001560] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND With clozapine, either crushed tablets suspended in an aqueous medium or proprietary suspension is sometimes prescribed as an alternative to tablets, but bioequivalence data are scant. METHODS We compared clozapine dose, and plasma clozapine and N -desmethylclozapine (norclozapine) concentrations after use of either tablets or crushed tablets/suspension in samples submitted for clozapine therapeutic drug monitoring, 1993 to 2017. RESULTS There were 846 patients (1646 samples) given crushed tablets/suspension and 6065 patients (10,779 samples) given tablets. The median dose (mg d -1 ) was significantly higher in men (500 vs 450) and women (500 vs 400) given crushed tablets/suspension, but the median plasma clozapine and norclozapine concentrations (mg L -1 ) were significantly lower (men: 0.29 and 0.22 vs 0.39 and 0.28; women: 0.35 and 0.26 vs 0.50 and 0.32, respectively). A subgroup of 480 patients was prescribed either crushed tablets/suspension (1016 samples) or tablets (1259 samples) at different times. The median dose was again significantly higher in men (500 vs 500) and women (500 vs 450), but the median plasma clozapine and norclozapine concentrations were significantly lower (men: 0.29 and 0.22 vs 0.32 and 0.24; women: 0.30 and 0.24 vs 0.38 and 0.29, respectively). IMPLICATIONS Poor adherence, sedimentation of suspension before use, and incomplete dosage are potential contributors to the lower median plasma clozapine and norclozapine concentrations observed after use of either crushed clozapine tablets or suspension as compared with tablets. Those administering crushed tablets/suspension should be aware of these factors.
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Wickramarachchi P, Boyd JM, Orton DJ. Biological Variation in Clozapine and Metabolite Reporting During Therapeutic Drug Monitoring. Clin Chim Acta 2022; 531:183-187. [DOI: 10.1016/j.cca.2022.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
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Brand BA, Haveman YRA, de Beer F, de Boer JN, Dazzan P, Sommer IEC. Antipsychotic medication for women with schizophrenia spectrum disorders. Psychol Med 2022; 52:649-663. [PMID: 34763737 PMCID: PMC8961338 DOI: 10.1017/s0033291721004591] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/13/2021] [Accepted: 10/22/2021] [Indexed: 12/24/2022]
Abstract
There are significant differences between men and women in the efficacy and tolerability of antipsychotic drugs. Here, we provide a comprehensive overview of what is currently known about the pharmacokinetics and pharmacodynamics of antipsychotics in women with schizophrenia spectrum disorders (SSDs) and translate these insights into considerations for clinical practice. Slower drug absorption, metabolism and excretion in women all lead to higher plasma levels, which increase the risk for side-effects. Moreover, women reach higher dopamine receptor occupancy compared to men at similar serum levels, since oestrogens increase dopamine sensitivity. As current treatment guidelines are based on studies predominantly conducted in men, women are likely to be overmedicated by default. The risk of overmedicating generally increases when sex hormone levels are high (e.g. during ovulation and gestation), whereas higher doses may be required during low-hormonal phases (e.g. during menstruation and menopause). For premenopausal women, with the exceptions of quetiapine and lurasidone, doses of antipsychotics should be lower with largest adjustments required for olanzapine. Clinicians should be wary of side-effects that are particularly harmful in women, such as hyperprolactinaemia which can cause oestrogen deficiency and metabolic symptoms that may cause cardiovascular diseases. Given the protective effects of oestrogens on the course of SSD, oestrogen replacement therapy should be considered for postmenopausal patients, who are more vulnerable to side-effects and yet require higher dosages of most antipsychotics to reach similar efficacy. In conclusion, there is a need for tailored, female-specific prescription guidelines, which take into account adjustments required across different phases of life.
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Affiliation(s)
- Bodyl A. Brand
- Department of Biomedical Sciences of Cells & Systems, Section Cognitive Neurosciences, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Yudith R. A. Haveman
- Department of Biomedical Sciences of Cells & Systems, Section Cognitive Neurosciences, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Franciska de Beer
- Department of Biomedical Sciences of Cells & Systems, Section Cognitive Neurosciences, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Janna N. de Boer
- Department of Biomedical Sciences of Cells & Systems, Section Cognitive Neurosciences, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Paola Dazzan
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, London, UK
| | - Iris E. C. Sommer
- Department of Biomedical Sciences of Cells & Systems, Section Cognitive Neurosciences, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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Clinical and genetic influencing factors on clozapine pharmacokinetics in Tunisian schizophrenic patients. THE PHARMACOGENOMICS JOURNAL 2021; 21:551-558. [PMID: 33731885 DOI: 10.1038/s41397-021-00231-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 02/04/2021] [Accepted: 02/22/2021] [Indexed: 02/02/2023]
Abstract
Clozapine (Clz) is an atypical antipsychotic, which its pharmacokinetics can be influenced by several factors. The CYP1A2 and CYP2C19, major enzymes implicated in Clz metabolism, present an interethnic variation on their activity caused by single nucleotide polymorphisms (SNPs). The present study investigated the influence of genetic and nongenetic factors on Clz pharmacokinetics in a southern Mediterranean population. We included adult Tunisian schizophrenic patients having received Clz and undergone a therapeutic drug monitoring (TDM) of Clz by morning C0 monitoring. The genomic DNA was extracted using a salting-out procedure. CYP1A2*1F (rs762551;-163C>A), CYP1A2*1C (rs2069514;-3860 G>A) and CYP 2C19*2 (rs4244285; 681G>A) was analyzed using PCR-RFLP. Fifty-one patients were enrolled in the study. The mutant allele (CYP1A2*1F) was the most frequently detected (58.8%). For CYP1A2*1F, Clz dose-normalized (C0/D ratio) was as high as 1.28 ± 0.37 in CC versus 0.67 ± 0.32 ng mL-1 per mg day-1 in AA group (p < 0.001). The influence of genetic (CYP1A2*1F, CYP1A2*1C and CYP2C19*2) and nongenetic parameters (age, weight, gender, tobacco, coffee, and alcohol consumption) on the variation of the Clz C0/D ratio was investigated. Only the CYP1A2*1 F polymorphism correlates significantly with the Clz C0/D variation and could explain 24% of its variability. Our data support a critical role of the CYP1A2 -163C>A on the variation of Clz exposure in Tunisian schizophrenic patients. Considering its narrow therapeutic range, CYP1A2 genotyping combined with TDM of Clz may improve efficacy and safety of this drug. Further studies are needed to investigate this issue.
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Lee J, Kim MG, Jeong HC, Shin KH. Physiologically-based pharmacokinetic model for clozapine in Korean patients with schizophrenia. Transl Clin Pharmacol 2021; 29:33-44. [PMID: 33854999 PMCID: PMC8020364 DOI: 10.12793/tcp.2021.29.e3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/18/2022] Open
Abstract
Clozapine has been used as a treatment of schizophrenia. Despite its large interindividual variability, few reports addressed the physiologically-based pharmacokinetic modeling and simulation (PBPK M&S) of clozapine in patients. This study aimed to develop a PBPK M&S of clozapine in Korean patients with schizophrenia. PBPK modeling for clozapine was constructed using a population-based PBPK platform, the SimCYP® Simulator (V19; Certara, Sheffield, UK). The PBPK model was developed by optimizing the physiological parameters of the built-in population and compound libraries in the SimCYP® Simulator. The model verification was performed with the predicted/observed ratio for pharmacokinetic parameters and visual predictive checks (VPCs) plot. Simulations were performed to predict toxicities according to dosing regimens. From published data, 230 virtual trials were simulated for each dosing regimen. The predicted/observed ratio for the area under the curve and peak plasma concentration was calculated to be from 0.78 to 1.34. The observation profiles were within the 5th and 95th percentile range with no serious model misspecification through the VPC plot. A significant impact on age and gender was found for clozapine clearance. The simulation results suggested that 150 mg twice a day and 150 mg three times a day of clozapine have toxicity concerns. In conclusion, a PBPK model was developed and reasonable parameters were made from the data of Korean patients with schizophrenia. The provided model might be used to predict the pharmacokinetics of clozapine and assist dose adjustment in clinical settings.
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Affiliation(s)
- Joomi Lee
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 41566, Korea
| | - Min-Gul Kim
- Center for Clinical Pharmacology and Biomedical Research Institute, Jeonbuk National University Hospital, Jeonju 54907, Korea.,Department of Pharmacology, School of Medicine, Jeonbuk National University, Jeonju 54907, Korea
| | - Hyeon-Cheol Jeong
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 41566, Korea
| | - Kwang-Hee Shin
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 41566, Korea
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13
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A systematic review and meta-analysis of the association between clozapine and norclozapine serum levels and peripheral adverse drug reactions. Psychopharmacology (Berl) 2021; 238:615-637. [PMID: 33410989 DOI: 10.1007/s00213-020-05746-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/01/2020] [Indexed: 12/13/2022]
Abstract
RATIONALE Clozapine is the most effective antipsychotic for treatment-refractory schizophrenia for reducing positive psychotic symptoms. It is associated with a reduction in hospitalisation and overall mortality. In spite of this, clozapine remains underutilised due to its complex adverse drug reaction (ADR) profile. OBJECTIVE This systematic review aims to investigate the association of clozapine and norclozapine serum levels, and peripheral ADRs. METHODS Studies were searched from four electronic databases (PubMed, EMBASE, PsycINFO and CINAHL) from inception to 12 June 2020. Studies were included if they had adult patients, provided data on steady-state trough clozapine or norclozapine levels and reported on clozapine-associated ADRs. Pregnant women, case reports and series were excluded. RESULTS A statistically significant correlation was found for clozapine serum levels and triglycerides (n = 70; r = 0.303, 95% CI 0.0119-0.546, p = 0.042), heart rate (n = 137; r = 0.269, 95% CI 0.0918-0.486, p = 0.035), and overall combined ADRs (n = 160; r = 0.264, 95% CI 0.110-0.405, p = 0.001), but not for absolute neutrophil count (n = 223; r = - 0.164, 95% CI - 0.529-0.253, p = 0.444) or total white cell count (n = 18; r = 0.0176, 95% CI - 0.203-0.237, p = 0.878). Interestingly, norclozapine serum levels were found to be statistically correlated to triglycerides (n = 120; r = 0.211, 95% CI 0.0305-0.378, p = 0.022), total cholesterol (n = 120; r = 0.272, 95% CI 0.0948-0.432, p = 0.003) and weight gain (n = 118; r = 0.208, 95% CI 0.0261-0.377, p = 0.025). CONCLUSIONS Heart rate, triglycerides and combined ADRs are significantly correlated with clozapine levels, and triglycerides, total cholesterol and weight gain with norclozapine levels. Future prospective, randomised controlled studies are needed to identify the cause-effect relationship between clozapine levels and peripheral ADRs.
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14
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Griffiths K, Millgate E, Egerton A, MacCabe JH. Demographic and clinical variables associated with response to clozapine in schizophrenia: a systematic review and meta-analysis. Psychol Med 2021; 51:376-386. [PMID: 33602358 DOI: 10.1017/s0033291721000246] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Clozapine is the only licensed pharmacotherapy for treatment-resistant schizophrenia. However, response to clozapine is variable. Understanding the demographic and clinical features associated with response to clozapine may be useful for patient stratification for clinical trials or for identifying patients for earlier initiation of clozapine. We systematically reviewed the literature to investigate clinical and demographic factors associated with variation in clozapine response in treatment-resistant patients with schizophrenia spectrum disorders. Subsequently, we performed a random-effects meta-analysis to evaluate differences in duration of illness, age at clozapine initiation, age of illness onset, body weight and years of education between clozapine responders and non-responders. Thirty-one articles were eligible for qualitative review and 17 of these were quantitatively reviewed. Shorter duration of illness, later illness onset, younger age at clozapine initiation, fewer hospitalisations and fewer antipsychotic trials prior to clozapine initiation showed a trend to be significantly associated with a better response to clozapine. Meta-analysis of seven studies, totalling 313 subjects, found that clozapine responders had a significantly shorter duration of illness compared to clozapine non-responders [g = 0.31; 95% confidence interval (CI) 0.06-0.56; p = 0.01]. The results imply that a delay in clozapine treatment may result in a poorer response and that a focus on prompt treatment with clozapine is warranted.
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Affiliation(s)
- Kira Griffiths
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Edward Millgate
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Alice Egerton
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - James H MacCabe
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
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15
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Ortega-Vázquez A, Mayen-Lobo YG, Dávila-Ortiz de Montellano DJ, Tristán-López L, Aviña-Cervantes CL, Ríos C, López-López M, Monroy-Jaramillo N. Alcohol intake potentiates clozapine adverse effects associated to CYP1A2*1C in patients with refractory psychosis. Drug Dev Res 2020; 82:685-694. [PMID: 33336447 DOI: 10.1002/ddr.21774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 12/24/2022]
Abstract
Clozapine (CLZ) is an atypical antipsychotic and the gold standard for refractory psychosis treatment. However, there is little information regarding pharmacogenetics of CLZ in patients with refractory psychosis and its clinical correlation with alcohol intake. Although neurological effects of CLZ in patients with concomitant alcohol intake are documented, its use is very common in patients with psychosis. We explored the impact of CYP1A2, CYP2D6, CYP2C19, and CYP3A4 genetic variants on CLZ pharmacokinetics and side effects, along with coffee/alcohol/tobacco consumption habits and clinical data of 48 adult patients with refractory psychosis on CLZ antipsychotic monotherapy. Relevant CYP variants in CLZ metabolism were evaluated by targeted genotyping and multiplex ligation-dependent probe amplification. CLZ and its main metabolite plasma concentrations were determined by high performance liquid chromatography. Biochemical and molecular data, along with other potential confounders, were included in the analysis by linear regression. Overall, CYP variants showed no effect on CLZ pharmacokinetics. The rs2069514 variant in homozygous genotype (also known as CYP1A2*1C/*1C) was associated with CLZ adverse reactions in Mexican patients with refractory psychosis (OR = 3.55 CI95 = 1.041-12.269, p = .043) and demonstrated that this effect is doubled by concomitant alcohol consumption (OR = 7.9 CI95 = 1.473-42.369, p = .016). Clinicians should be aware of this information before starting CLZ use, when treating patients with refractory psychosis, who are alcohol drinkers and carriers of this genetic variant in order to prevent CLZ-related adverse reactions. Nevertheless, our findings should be replicated in larger samples.
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Affiliation(s)
- Alberto Ortega-Vázquez
- Department of Biological Systems, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
| | - Yerye G Mayen-Lobo
- Department of Biological Systems, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico.,Master's Program in Pharmaceutical Sciences, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
| | | | - Luis Tristán-López
- Department of Neurochemistry, National Institute of Neurology and Neurosurgery, "Manuel Velasco Suárez", Mexico City, Mexico
| | - Carlos L Aviña-Cervantes
- Department of Psychiatry, National Institute of Neurology and Neurosurgery, "Manuel Velasco Suárez", Mexico City, Mexico
| | - Camilo Ríos
- Department of Biological Systems, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico.,Master's Program in Pharmaceutical Sciences, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico.,Department of Neurochemistry, National Institute of Neurology and Neurosurgery, "Manuel Velasco Suárez", Mexico City, Mexico
| | - Marisol López-López
- Department of Biological Systems, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
| | - Nancy Monroy-Jaramillo
- Department of Genetics, National Institute of Neurology and Neurosurgery, "Manuel Velasco Suárez", Mexico City, Mexico
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16
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Association of clozapine-related metabolic disturbances with CYP3A4 expression in patients with schizophrenia. Sci Rep 2020; 10:21283. [PMID: 33277605 PMCID: PMC7718230 DOI: 10.1038/s41598-020-78474-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/25/2020] [Indexed: 11/09/2022] Open
Abstract
Clozapine is effective in treatment-resistant schizophrenia; however, adverse effects often result in discontinuation of clozapine therapy. Many of the side-effects are associated with pharmacokinetic variations; therefore, the expression of major clozapine-metabolizing enzymes (CYP1A2, CYP3A4) in patients may predict development of adverse effects. In patients with schizophrenia (N = 96), development of clozapine concentration-dependent metabolic side-effects was found to be associated with pharmacokinetic variability related to CYP3A4 but not to CYP1A2 expression. In low CYP3A4 expressers, significant correlation was detected between fasting glucose level and clozapine concentration; moreover, the incidence of abnormal glucose level was associated with exaggerated clozapine concentrations (> 600 ng/ml). In low CYP3A4 expressers, exaggerated concentrations were more frequently observed than in normal/high expressers. Moderate/high risk obesity (BMI ≥ 35) more frequently occurred in low CYP3A4 expresser patients than in normal/high expressers. In patients with normal/high CYP3A4 expression and consequently with extensive clozapine-metabolizing capacity, norclozapine/clozapine ratio correlated with fasting glucose levels, triglyceride concentrations and BMI. Low CYP3A4 expression often resulting in exaggerated clozapine concentrations was considered to be as an important risk factor for some concentration-dependent adverse effects as normal/high CYP3A4 expression evoking high norclozapine/clozapine ratios. CYP3A4-status can identify patients with increased risk for metabolic side-effects and prevent their development by careful therapeutic strategy.
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17
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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: 50] [Impact Index Per Article: 12.5] [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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18
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Do Indian patients with schizophrenia need half the recommended clozapine dose to achieve therapeutic serum level? An exploratory study. Schizophr Res 2020; 222:195-201. [PMID: 32518001 DOI: 10.1016/j.schres.2020.05.057] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/18/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022]
Abstract
Inter-racial differences in serum clozapine have received less scientific importance, as there are fewer studies on therapeutic drug monitoring (TDM) from Asia. We measured the serum clozapine levels in 142 patients with schizophrenia and related disorders at a tertiary care psychiatric institute in India. The clozapine concentration per milligram (mg) of oral clozapine dose (C/D ratio) was calculated, and the C/D ratio was used to estimate oral clozapine dose needed to achieve therapeutic serum clozapine level (350 ng/ml). This study examined Indian patients only and compared the results with weighted mean serum clozapine and its correlates in Caucasian population, based on published scientific literature. The median C/D ratio in our sample was 2.5 (n = 142), and the clozapine dose needed to achieve therapeutic serum clozapine level was 140 mg/d. The median C/D ratio of our subjects was nearly two and a half times higher than the weighted mean C/D ratio of Caucasians (2.5 v/s 1.07) reported elsewhere. After excluding the significant pharmacokinetic interactions and stratifying according to gender and smoking status, the estimated clozapine dose to achieve therapeutic serum level in male smokers (n = 9) and female non-smokers (n = 38) were 238 mg/d (C/D ratio; 1.47) and 120 mg/d (C/D ratio:2.93) respectively. On comparing, male smokers (600 mg/d versus 238 mg/d) and female non-smokers (300 mg/d versus 120 mg/d) in our study needed about 40% of the recommended clozapine dose for Caucasians to achieve therapeutic serum clozapine level. The pharmacogenetic correlates of lesser clozapine dose requirement in the Indian population require further research.
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19
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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: 18] [Impact Index Per Article: 4.5] [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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20
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Exploring the Prevalence of Clozapine Phenotypic Poor Metabolizers in 4 Asian Samples: They Ranged Between 2% and 13. J Clin Psychopharmacol 2020; 39:644-648. [PMID: 31688448 DOI: 10.1097/jcp.0000000000001125] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE/BACKGROUND Clozapine clearance is influenced by sex, smoking status, ethnicity, coprescription of inducers or inhibitors, obesity, and inflammation. In 126 Beijing inpatients, we measured repeated trough steady-state serum concentrations and identified 4% (5/126) who were phenotypical poor metabolizers (PMs); none were ultrarapid metabolizers (UMs). They were defined as being 2 SDs beyond the means of total clozapine concentration/dose ratios stratified by sex and smoking. Using this definition, this study explores the prevalence of PMs and UMs using data from 4 already published Asian samples. Three samples were East Asian (Beijing 2, Taipei, and Seoul); one was from South India (Vellore). FINDINGS/RESULTS The prevalence of phenotypical PMs ranged from 2% to 13%, but inflammation was not excluded. The prevalence was 7% (14/191) for Beijing 2, 11% (8/70) for Taipei, 13% (9/67) for Seoul, and 2% (2/101) for the Vellore sample. Five phenotypic PMs appeared to be associated with extreme obesity. Phenotypic UM prevalence ranged from 0% to 1.6% but may be partly explained by lack of adherence. A Vellore phenotypic UM appeared to be associated with induction through high coffee intake. IMPLICATIONS/CONCLUSIONS Approximately 10% of Asians may be clozapine PMs and may need only 50 to 150 mg/d to get therapeutic concentrations. Future studies combining gene sequencing for new alleles with repeated concentrations and careful control of confounders including inhibitors, inflammation, and obesity should provide better estimations of the prevalence of phenotypic clozapine PMs across races. Clozapine UM studies require excluding potent inducers, careful supervision of compliance in inpatient settings, and multiple serum concentrations.
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21
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Kim J, Plitman E, Iwata Y, Nakajima S, Mar W, Patel R, Chavez S, Chung JK, Caravaggio F, Chakravarty MM, Remington G, Gerretsen P, Graff-Guerrero A. Neuroanatomical profiles of treatment-resistance in patients with schizophrenia spectrum disorders. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109839. [PMID: 31843627 DOI: 10.1016/j.pnpbp.2019.109839] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/10/2019] [Accepted: 12/12/2019] [Indexed: 01/18/2023]
Abstract
Widespread structrual abnormalities in subcortical brain regions have been identified in patients with schizophrenia. However, only a few studies have examined the neuroanatomical profiles of patients with treatment-resistant schizophrenia. The aim of this study was to compare differences in subcortical and hippocampal volumes between: (i) treatment-resistant patients who are non-responders to both first-line antipsychotics and clozapine (URS), (ii) treatment-resistant patients who are non-responders to first-line antipsychotics but are responders to clozapine (CLZ-Resp), (iii) responders to first-line antipsychotics (FL-Resp), and (iv) healthy controls. T1-weighted images of 103 participants (27 URS, 29 CLZ-Resp, 21 FL-Resp, and 26 healthy controls) were obtained. Group differences in striatal, thalamic, globus pallidus, amygdala, and hippocampus volumes were examined. Multiple regression analyses were performed to examine the associations between subcortical and hippocampal volumes and participant characteristics. The FL-Resp group showed larger striatal and globus pallidus volumes compared to the URS group and larger post-commissural putamen and globus pallidus volumes compared to healthy controls. The URS group showed smaller thalamic volume compared to healthy controls. There were no subcortical or hippocampal volume differences between the URS and CLZ-Resp groups. Differences in subcortical and hippocampal structural volumes were not related to symptom severity or chlorpromazine antipsychotic dose equivalents. Our findings suggest different structural volume alterations in subcortical brain regions between treatment-resistant schizophrenia and responders to first-line antipsychotics. Whether subcortical structure compromise is a distinct pathophysiological marker of treatment-resistant schizophrenia, or a result of antipsychotic exposure, remains to be explored.
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Affiliation(s)
- Julia Kim
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Eric Plitman
- Cerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Yusuke Iwata
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | | | - Wanna Mar
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Raihaan Patel
- Cerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada; Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Sofia Chavez
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Jun Ku Chung
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Fernando Caravaggio
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - M Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Gary Remington
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, Ontario, Canada; Schizophrenia Division, CAMH, Toronto, Ontario, Canada
| | - Philip Gerretsen
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, CAMH, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, Ontario, Canada
| | - Ariel Graff-Guerrero
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, CAMH, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, Ontario, Canada.
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22
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Jovanović M, Vučićević K, Miljković B. Understanding variability in the pharmacokinetics of atypical antipsychotics - focus on clozapine, olanzapine and aripiprazole population models. Drug Metab Rev 2020; 52:1-18. [PMID: 32008418 DOI: 10.1080/03602532.2020.1717517] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Antipsychotic medicines are widely used for the management of psychotic symptoms regardless of the underlying diagnosis. Most atypical antipsychotics undergo extensive metabolism prior to excretion. Various factors may influence their pharmacokinetics, particularly elimination, leading to highly variable drug concentrations between individual patients following the same dosing regimen. Population pharmacokinetic approach, based on nonlinear mixed effects modeling, is a useful tool to identify covariates explaining pharmacokinetic variability, as well as to characterize and distinguish unexplained residual and between-subject (interindividual) variability. In addition, this approach allows the use of both sparsely and intensively sampled data. In this paper, we reviewed the pharmacokinetic characteristics of clozapine, olanzapine and aripiprazole, focusing on a population modeling approach. In particular, models based on a nonlinear mixed effects approach performed by NONMEM® software in order to identify and quantify sources of pharmacokinetic variability are presented. Population models were identified through systematic searches of PubMed and sixteen studies were selected. Some of the factors identified that significantly contribute to variability in elimination among clozapine, olanzapine, and aripiprazole are demographic characteristics, body weight, genetic polymorphism, smoking and in some cases drug interactions. Scientific research based on pharmacometric modeling is useful to further characterize sources of variability and their combined effect.
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Affiliation(s)
- Marija Jovanović
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Katarina Vučićević
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Branislava Miljković
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
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23
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Albitar O, Harun SN, Zainal H, Ibrahim B, Sheikh Ghadzi SM. Population Pharmacokinetics of Clozapine: A Systematic Review. BIOMED RESEARCH INTERNATIONAL 2020; 2020:9872936. [PMID: 31998804 PMCID: PMC6970501 DOI: 10.1155/2020/9872936] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND OBJECTIVE Clozapine is a second-generation antipsychotic drug that is considered the most effective treatment for refractory schizophrenia. Several clozapine population pharmacokinetic models have been introduced in the last decades. Thus, a systematic review was performed (i) to compare published pharmacokinetics models and (ii) to summarize and explore identified covariates influencing the clozapine pharmacokinetics models. METHODS A search of publications for population pharmacokinetic analyses of clozapine either in healthy volunteers or patients from inception to April 2019 was conducted in PubMed and SCOPUS databases. Reviews, methodology articles, in vitro and animal studies, and noncompartmental analysis were excluded. RESULTS Twelve studies were included in this review. Clozapine pharmacokinetics was described as one-compartment with first-order absorption and elimination in most of the studies. Significant interindividual variations of clozapine pharmacokinetic parameters were found in most of the included studies. Age, sex, smoking status, and cytochrome P450 1A2 were found to be the most common identified covariates affecting these parameters. External validation was only performed in one study to determine the predictive performance of the models. CONCLUSIONS Large pharmacokinetic variability remains despite the inclusion of several covariates. This can be improved by including other potential factors such as genetic polymorphisms, metabolic factors, and significant drug-drug interactions in a well-designed population pharmacokinetic model in the future, taking into account the incorporation of larger sample size and more stringent sampling strategy. External validation should also be performed to the previously published models to compare their predictive performances.
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Affiliation(s)
- Orwa Albitar
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Sabariah Noor Harun
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Hadzliana Zainal
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
| | - Baharudin Ibrahim
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, George Town, Penang, Malaysia
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de Leon J, Rajkumar AP, Kaithi AR, Schoretsanitis G, Kane JM, Wang CY, Tang YL, Lin SK, Hong KS, Farooq S, Ng CH, Ruan CJ, Andrade C. Do Asian Patients Require Only Half of the Clozapine Dose Prescribed for Caucasians? A Critical Overview. Indian J Psychol Med 2020; 42:4-10. [PMID: 31997860 PMCID: PMC6970303 DOI: 10.4103/ijpsym.ijpsym_379_19] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 09/24/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Since 1997, studies have found that Asians need lower clozapine doses than Caucasians. Caucasians with average clozapine metabolism may need from 300 to 600 mg/day to reach the therapeutic range (350 ng/ml). Thus, serum clozapine concentration-to-dose (C/D) ratios typically range between 0.60 (male smokers) and 1.20 (female non-smokers). A 2019 systematic review of clozapine levels demonstrated weighted mean C/D ratios of 1.57 in 876 East Asians and 1.07 in 1147 Caucasians (P < .001). In Asian countries, average clozapine doses are lower than 300 mg/day. After sex and smoking stratification in 5 Asian samples with clozapine concentrations, the clozapine dose required to reach 350 ng/ml in female non-smokers ranged from 145 to 189 mg/day and in male smokers, from 259 to 294 mg/day. Thus, in Asian patients with average metabolism (with no inducers other than smoking, with no inhibitors, and in the absence of extreme obesity), the dose needed for clinical response may range between 150 mg/day for female non-smokers to 300 mg/day for male smokers. Clozapine levels may help personalize dosing in clozapine poor metabolizers (PMs) and ultrarapid metabolizers (UMs). Asian PMs may need very low doses (50-150 mg/day) to obtain therapeutic concentrations. About 10% (range 2-13%) of Asians are genetic PM cases. Other PMs are patients taking CYP1A2 inhibitors such as fluvoxamine, oral contraceptives, and valproate. Temporary clozapine PM status may occur during severe systemic infections/inflammations with fever and C-reactive protein (CRP) elevations. Asian UMs include patients taking potent inducers such as phenytoin, and rarely, valproate.
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Affiliation(s)
- Jose de Leon
- Mental Health Research Center, Eastern State Hospital, Lexington, Kentucky, USA.,Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain, and Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apóstol Hospital, University of the Basque Country, Vitoria, Spain
| | - Anto P Rajkumar
- Department of Psychiatry, Christian Medical College, Vellore, Tamil Nadu, India.,Institute of Mental Health, University of Nottingham, Nottingham, United Kingdom
| | | | - Georgios Schoretsanitis
- Department of Psychiatry, Zucker Hillside Hospital, Northwell Health, Glen Oaks, New York, USA
| | - John M Kane
- Department of Psychiatry, Zucker Hillside Hospital, Northwell Health, Glen Oaks, New York, USA.,Department of Psychiatry and Molecular Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Chuan-Yue Wang
- Department of Psychiatry, The National Clinical Research Centre for Mental Disorders and Beijing Key Lab of Mental Disorders and Beijing Institute for Brain Disorders Center of Schizophrenia, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Yi-Lang Tang
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, and Substance Abuse Treatment Program, Atlanta VA Medical Center, Decatur, Georgia, USA
| | - Shih-Ku Lin
- Department of General Psychiatry, Taipei City, Psychiatric Center, Taipei, Taiwan, and Department of Psychiatry, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Kyung Sue Hong
- Department of Psychiatry, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea
| | - Saeed Farooq
- School of Primary, Community and Social Care, Faulty of Medicine and Health Sciences, Keele University, Staffordshire, and Midlands Partnership NHS Foundation Trust, Staffordshire, United Kingdom
| | - Chee H Ng
- Department of Psychiatry, The Melbourne Clinic and St Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - 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
| | - Chittaranjan Andrade
- Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
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25
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Schoretsanitis G, Kane JM, Ruan CJ, Spina E, Hiemke C, de Leon J. A comprehensive review of the clinical utility of and a combined analysis of the clozapine/norclozapine ratio in therapeutic drug monitoring for adult patients. Expert Rev Clin Pharmacol 2019; 12:603-621. [DOI: 10.1080/17512433.2019.1617695] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Georgios Schoretsanitis
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - John M. Kane
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Can-Jun Ruan
- Laboratory of Clinical Psychopharmacology & The National Clinical Research Centre for Mental Disorders & Beijing Key Lab of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Christoph Hiemke
- Department of Psychiatry and Psychotherapy, University Medical Center of Mainz, Mainz, Germany
| | - Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, KY, USA
- Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain
- Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apostol Hospital, University of the Basque Country, Vitoria, Spain
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26
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Seeman MV. Men and women respond differently to antipsychotic drugs. Neuropharmacology 2019; 163:107631. [PMID: 31077728 DOI: 10.1016/j.neuropharm.2019.05.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 04/19/2019] [Accepted: 05/07/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Because women are often perceived as having better outcomes than men in psychotic illnesses such as schizophrenia - women are less often in hospital, have a lower suicide rate, are less often involved with the law, enjoy better relationships with family and friends - the question arises as to whether or not this apparent advantage is attributable to a gender difference in antipsychotic response. OBJECTIVE The aim of this paper is to critically review the quantitative and qualitative literature on gender difference in antipsychotic response sourced mainly from medical databases of the last ten years. FINDINGS There are theoretical reasons why women's effective doses of antipsychotics might need to be lower than guidelines recommend for men, especially as regards olanzapine and clozapine, but, because there are so many variables that impinge on antipsychotic response, it is difficult to provide definitive guidance. What is evident is that some antipsychotic side effects, weight gain for instance, are more worrisome for women than for men. It is also evident that, after menopause, women need an increase in their antipsychotic dose; other reproductive stages in women's lives require special prescribing considerations as well. CONCLUSION There is a science, and an art, to prescribing antipsychotics, which needs to take gender into account. This article is part of the issue entitled 'Special Issue on Antipsychotics'.
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Affiliation(s)
- Mary V Seeman
- Department of Psychiatry, University of Toronto, 260 Heath St. West, Toronto, Ontario, M5P 3L6, Canada.
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27
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Clozapine Metabolism in East Asians and Caucasians: A Pilot Exploration of the Prevalence of Poor Metabolizers and a Systematic Review. J Clin Psychopharmacol 2019; 39:135-144. [PMID: 30811372 DOI: 10.1097/jcp.0000000000001018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE/BACKGROUND In clozapine therapeutic drug monitoring (TDM) studies, Chinese reached the same concentrations using half the dosage Caucasians use. Defining clozapine poor metabolizers (PMs) requires stratification by ethnicity, smoking, and sex. METHODS/PROCEDURES After sex and smoking stratification in 129 Chinese inpatients (mean, 8.8 TDM samples per patient), we explored the association between the total concentration-dose (C/D) ratio and CYP1A2 (*1C, *1F, and *7) and CYP2C19 alleles (*2 and *3). A systematic literature review identified 22 clozapine TDM prior studies (13 in Caucasians and 7 in East Asians). FINDINGS/RESULTS In our Chinese sample, the mean total clozapine C/D ratio (ng/mL per mg/d) was 1.96 for 22 male smokers, 2.07 for 5 female smokers, 2.47 for 36 male nonsmokers, and 2.95 for 66 female nonsmokers. CYP1A2 *1C had no significant effects, and CYP1A2 *1F had small effects. Five clozapine PMs (4%) needed low clozapine doses of 75 to 115 mg/d to get therapeutic concentrations. Using the same methodology in a published Italian sample, we found 5 PMs (3.3% of 152). In the systematic review, the clozapine C/D ratio (ng/mL per mg/d) was higher when comparing: (1) weighted mean values of 1.57 in 876 East Asians versus 1.07 in 1147 Caucasians and (2) ranks of 8 East Asians versus 13 Caucasian samples (P < 0.001). IMPLICATIONS/CONCLUSIONS Future TDM studies need to further explore the frequency of clozapine PMs after sex and smoking stratification in East Asian and Caucasian patients. Compared with Caucasians, East Asians appear to have a clinically relevant decrease in clozapine clearance.
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28
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Kikuchi YS, Kanbayashi T, Shimizu T. Relationship between Clozapine-Induced Electroencephalogram Abnormalities and Serum Concentration of Clozapine in Japanese Patients with Treatment-Resistant Schizophrenia. Psychiatry Investig 2018; 16:279-284. [PMID: 30947495 PMCID: PMC6504775 DOI: 10.30773/pi.2018.12.16] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 12/16/2018] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE The objective of this study was to investigate the relationship between the serum concentration of clozapine (C-CLZ), Ndesmethylclozapine (N-CLZ) and the daily dose of CLZ (D-CLZ), and the relationships among CLZ and electroencephalogram (EEG) abnormalities. METHODS Twenty-eight patients were recruited to this study, but 8 patients were excluded because clozapine was discontinued before the post-treatment measurement of EEG or C-CLZ. Ultimately, 20 patients (6 men, 14 women) with an average age of 36 years were enrolled. The subjects were divided into EEG normal and abnormal groups. C-CLZ and N-CLZ were measured at 4, 12, 26, and 52 weeks after initiating CLZ administration. RESULTS All patients had normal baseline EEG signals, and 8 patients showed EEG abnormalities later. There were significant correlations between C-CLZ and D-CLZ, and between N-CLZ and D-CLZ. The C-CLZ/D-CLZ, N-CLZ/D-CLZ, and C-CLZ/N-CLZ ratio were not significantly different between the EEG normal and EEG abnormal groups. The EEG abnormal group had significant higher proportion of patients with high intra-individual variability in their C-CLZ/D-CLZ ratio. CONCLUSION There is no relationship between C-CLZ and EEG abnormalities. However, patients with high intra-individual variability in their C-CLZ/D-CLZ ratio had greater possibility of exhibiting EEG abnormalities.
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Affiliation(s)
- Yuka Sugawara Kikuchi
- Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Takashi Kanbayashi
- Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Tetsuo Shimizu
- Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
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29
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Mayerova M, Ustohal L, Jarkovsky J, Pivnicka J, Kasparek T, Ceskova E. Influence of dose, gender, and cigarette smoking on clozapine plasma concentrations. Neuropsychiatr Dis Treat 2018; 14:1535-1543. [PMID: 29950838 PMCID: PMC6011879 DOI: 10.2147/ndt.s163839] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION Therapeutic drug monitoring (TDM) of clozapine is a very useful method for verifying both the correct intake and the interindividual variability of its metabolism, thereby avoiding the risk of toxicity. The purposes of this paper were to discover how many patients using clozapine in common clinical practice have clozapine plasma concentration (PC) levels in the proposed reference range and to identify factors that influence clozapine PC levels. METHODS Our study included 100 inpatients (diagnosed with schizophrenia or schizoaffective disorder) taking standard doses of clozapine (100-700 mg/day). Clozapine concentration was measured by high-performance liquid chromatography. Correlations between doses and PC levels and the influence of smoking and gender on clozapine PC levels were calculated. RESULTS A large number of the patients (67%) had PC levels outside the proposed reference range. The clozapine PC levels were influenced by dose, gender, and cigarette smoking. CONCLUSION The correlations between dose, gender, and cigarette smoking and clozapine PC levels highlighted by our study overlap other research. It was surprising to find such a large number of patients with clozapine PC levels outside the therapeutic range. This result suggests the importance of clozapine TDM due to misunderstood inter- and/or intraindividual variability or misestimated partial therapeutic compliance.
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Affiliation(s)
- Michaela Mayerova
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Department of Psychiatry, University Hospital Brno, Brno, Czech Republic.,CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Libor Ustohal
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Department of Psychiatry, University Hospital Brno, Brno, Czech Republic.,CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jiri Jarkovsky
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Jan Pivnicka
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Institute of Forensic Medicine, St. Anne's University Hospital, Masaryk University, Brno, Czech Republic
| | - Tomas Kasparek
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Department of Psychiatry, University Hospital Brno, Brno, Czech Republic
| | - Eva Ceskova
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
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30
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Castberg I, Westin AA, Skogvoll E, Spigset O. Effects of age and gender on the serum levels of clozapine, olanzapine, risperidone, and quetiapine. Acta Psychiatr Scand 2017; 136:455-464. [PMID: 28865402 DOI: 10.1111/acps.12794] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/02/2017] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To investigate serum concentrations of second-generation antipsychotics in relation to age and gender in a population ranging from 18 to 100 years. METHOD Results from a routine therapeutic drug monitoring database were retrieved, and 43 079 samples from 11 968 patients were included (17 249 samples for clozapine, 16 171 samples for olanzapine, 5343 samples for risperidone, and 4316 samples for quetiapine). The dose-adjusted concentration was used as the primary target variable. A linear mixed model was used to allow the inclusion of multiple samples from each patient. RESULTS Age had a significant impact on the concentrations of all four drugs. At the age of 80, the dose-adjusted concentrations were up to twice those of the age of 40. At the age of 90, dose-adjusted concentrations were two- to three-fold higher. Age-related increases were largest for clozapine (+108% at 80 years; +197% at 90 years) and smallest for olanzapine (+28% at 80 years; +106% at 90 years). Females generally had dose-adjusted concentrations 20-30% higher than males. CONCLUSION The effect of age on the serum concentrations of the antipsychotics studied becomes pronounced with advanced age. The patient population aged above 70 should be subdivided according to exact age, and considerable dose reductions are recommended.
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Affiliation(s)
- I Castberg
- Østmarka Psychiatric Department, St. Olav University Hospital, Trondheim, Norway
| | - A A Westin
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.,Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway
| | - E Skogvoll
- Department of Anaesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway
| | - O Spigset
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.,Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway
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Abstract
We aimed to evaluate the association between sex and hospitalization characteristics in psychotic disorders. We identified all acute hospitalizations, between 2010 and 2013, for psychotic disorders in patients younger than 45 and older than 55 years (n = 5411) in the hospital's database. In addition, we identified patients who were prescribed with intramuscular risperidone (n = 280) or clozapine (n = 192) at discharge. The results showed that women younger than 45 years had lower proportions of hospitalizations (33.52% vs. 66.47%) and involuntary hospitalizations (33.85% vs. 45.55%) than did men in the same age group. Women older than 55 years had higher proportions of hospitalizations (57.22% vs. 42.77%) and similar proportion of involuntary hospitalizations. Women younger than 45 years were prescribed similar doses of intramuscular risperidone and lower doses of clozapine (345.8 vs. 380.2 mg) and women older than 55 years were prescribed higher doses of intramuscular risperidone (44.8 vs. 34.4 mg/2 weeks) and clozapine (164.32 vs. 154.5 mg) than were men in the same age group. Women in the reproductive years have better hospitalization characteristics than do men on these measures.
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32
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Xie C, Pogribna M, Word B, Lyn‐Cook L, Lyn‐Cook BD, Hammons GJ. In vitro analysis of factors influencing CYP1A2 expression as potential determinants of interindividual variation. Pharmacol Res Perspect 2017; 5:e00299. [PMID: 28357125 PMCID: PMC5368963 DOI: 10.1002/prp2.299] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/14/2016] [Accepted: 01/10/2017] [Indexed: 12/17/2022] Open
Abstract
Individual differences in drug metabolism contribute to interindividual variation that characterizes responses to drugs and risk in exposure to foreign chemicals. Large individual differences are found in expression levels of CYP1A2, a major drug-metabolizing enzyme. Underlying causes for this variation are not well understood. Several factors, including tobacco smoking, consumption of cruciferous vegetables, and sex, have been associated with modulating CYP1A2 expression. To understand factors regulating expression of CYP1A2 in establishing a causal relationship, this study examined effects of cigarette smoke condensate (CSC), indole-3-carbinol (I3C), and 17β-estradiol (estradiol) on CYP1A2 expression in in vitro systems using human liver and lung cells. Treatment with CSC (2-25 μg/mL) significantly increased levels of CYP1A2 in six cell lines examined, in a concentration- and time-dependent manner. Fold changes in expression levels relative to controls varied among cell lines. CYP1A2 enzymatic activity also increased with CSC exposure. Treatment of H1299 and HepB3 cells with dietary agent I3C (50 and 100 μmol/L) increased CYP1A2 expression. In human cell lines H1299 and H1395, treatment with estradiol (10 and 100 nmol/L) significantly reduced expression of CYP1A2. Using ChIP assays, effects of CSC on histone modifications were analyzed. Increases in H3K4me3 and H4K16ac were observed at several segments in the CYP1A2 gene, whereas H3K27me3 decreased, following CSC treatment. These results suggest that CYP1A2 expression is affected epigenetically by CSC. Additional studies will be needed to further establish regulatory mechanisms underlying effects of various environmental, dietary, and endogenous factors on CYP1A2 expression in better predicting individual variation.
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Affiliation(s)
- ChengHui Xie
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
| | - Marta Pogribna
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
| | - Beverly Word
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
| | - Lascelles Lyn‐Cook
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
| | - Beverly D. Lyn‐Cook
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
| | - George J. Hammons
- Division of Biochemical ToxicologyFDA/National Center for Toxicological ResearchJeffersonArkansas72079
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33
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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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Seppälä N, Leinonen E, Viikki M, Solismaa A, Nuolivirta T, Kampman O. Factors associated with subjective side-effects during clozapine treatment. Nord J Psychiatry 2015; 69:161-6. [PMID: 25225739 DOI: 10.3109/08039488.2014.947321] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Clozapine is associated with subjectively unpleasant or clinically serious side-effects, which may affect treatment adherence. The aims of the study were to explore the association of clozapine+ norclozapine serum concentration and other factors with subjective side-effects in schizophrenia patients. METHODS In this cross-sectional study, 237 patients with a diagnosis of schizophrenia, schizo-affective or other non-organic psychoses completed the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS), a self-report scale measuring side-effects of antipsychotics and a clinical questionnaire. Clozapine+ norclozapine serum concentration of 190 patients was measured. Of the patients 80 (33.7%) were on antipsychotic combination therapy. RESULTS Higher clozapine+ norclozapine concentrations were associated with the depression-anxiety factor of LUNSERS and antipsychotic combination treatments were associated with sympatichotonia-tension factor. Younger patients reported sedation more often than older patients. CONCLUSION According to the present results, high clozapine concentrations were associated with depression-anxiety symptoms, but the causality remains unknown.
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Affiliation(s)
- Niko Seppälä
- Niko Seppälä, Department of Psychiatry, Satakunta Hospital District, University of Tampere , FI-29200 Harjavalta , and Medical School, Faculty of Medicine, University of Tampere , FI-33140 Tampere , Finland
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Abstract
BACKGROUND Both obesity and smoking are common in schizophrenia patients taking clozapine, causing cardiovascular disease and premature deaths. METHODS Two hundred and thirty-seven patients with schizophrenia or related psychoses treated with clozapine completed the Liverpool University Neuroleptic Assessment Scale (LUNSERS) and a questionnaire including current height, weight, changes therein and smoking status. AIMS The aim of this study was to analyze weight and weight change in smoking and non-smoking patients taking clozapine. A possible interaction between obesity and smoking was explored. RESULTS No association was found between weight change and smoking status during clozapine treatment. There was no significant difference in body mass index (BMI) between non-smokers and smokers. In the analysis of covariance (ANCOVA) with BMI as the dependent variable, the best fitting model comprised age, sex, intensity of sedation, and reported amount of smoking as explanatory variables (ηp(2)= 0.116; P = 0.029; power = 0.750). None of the explanatory proportions of any single factor was significant. CONCLUSIONS Estimated according to reported weight gain and BMI, no difference was found between smoking and non-smoking clozapine-treated patients. Number of cigarettes smoked explained BMI if age and sex were taken into account. This result is in line with the findings of some general population studies, where heavy smoking has been associated with a greater risk of obesity.
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Affiliation(s)
- Niko Seppälä
- Niko Seppälä, Department of Psychiatry, Satakunta Hospital District , FI-28500 Pori , and School of Medicine, University of Tampere , FI-33140 Tampere , Finland
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Socioeconomic factors influencing antipsychotic prescription for schizophrenia inpatients in China: a cross-sectional study. Int Clin Psychopharmacol 2014; 29:288-95. [PMID: 24323200 DOI: 10.1097/yic.0000000000000024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Medication is critical in schizophrenia therapy, and prescription patterns have changed considerably over the past 20 years in China. This study attempts to evaluate the prescription patterns of antipsychotics for inpatients with schizophrenia in China and to identify factors influencing these patterns. Claims data of inpatients diagnosed with schizophrenia in 2010 were derived from the reimbursement database of Wuhan and Wuxi. A total of 5251 inpatients received antipsychotic medications, of whom 29.0% received second-generation antipsychotics apart from clozapine (SGAs#), 13.7% received clozapine (CLO), 13.5% received first-generation antipsychotics (FGAs), 43.8% received at least both drug classes, and 5.1% used FGAs, CLO as well as SGAs#. Multinomial logistic regression for 2904 identified inpatients showed that factors of drug reimbursement policy, duration of hospitalization, age group, and municipality were statistically significant in antipsychotic medication. Drug list B and the 25-45 age group presented a significant relationship with SGAs# prescription (FGAs vs. SGAs#). Furthermore, the 12-30-day duration of hospitalization and the 25-45 age group showed a significant relationship with SGAs# prescription (CLO vs. SGAs#). Socioeconomic factors such as health insurance policies, especially reimbursement policy of drugs and payment system, as well as mental health resource distribution are important in antipsychotic prescription in China.
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Adverse Effects of Clozapine in Older Patients: Epidemiology, Prevention and Management. Drugs Aging 2013; 31:11-20. [DOI: 10.1007/s40266-013-0144-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Kohlrausch FB, Severino-Gama C, Lobato MI, Belmonte-de-Abreu P, Carracedo A, Hutz MH. The CYP1A2 -163C>A polymorphism is associated with clozapine-induced generalized tonic-clonic seizures in Brazilian schizophrenia patients. Psychiatry Res 2013; 209:242-5. [PMID: 23601795 DOI: 10.1016/j.psychres.2013.02.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/04/2013] [Accepted: 02/21/2013] [Indexed: 11/26/2022]
Abstract
We evaluated two polymorphisms at CYP1A2 (*1C and *1F) in a sample of 108 European-derived patients with schizophrenia and their influence on the pro-convulsive effect of clozapine. We found the *1F/*1F genotype to be significantly associated with seizures, and no relationship was observed with combinations of *1F and *1C alleles.
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Nielsen J, Kane JM, Correll CU. Real-world effectiveness of clozapine in patients with bipolar disorder: results from a 2-year mirror-image study. Bipolar Disord 2012; 14:863-9. [PMID: 23107278 DOI: 10.1111/bdi.12018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Clozapine remains the drug of choice for treatment-resistant schizophrenia but the evidence for its use in severe bipolar disorder (BD) remains sparse. METHODS A pharmaco-epidemiologic database study was carried out in Denmark, investigating the effectiveness of clozapine in BD patients (without a schizophrenia-spectrum disorder), between 1996 and 2007, using a two-year mirror-image design. RESULTS A total of 21473 patients with a lifetime diagnosis of International Classification of Diseases-10 (ICD-10) BD were identified, of which only 326 (1.5%) were treated with clozapine and were included in the mirror-image analysis. The mean follow-up time was 544 ± 280 days, the mean clozapine dose was 307.4 mg [95% confidence interval (CI): 287.9-328.2], and 39.3% were male. During clozapine treatment, the mean number of bed-days decreased from 177.8 (95% CI: 149.4-211.6) to 34.6 (95% CI: 24.8-48.2) (p < 0.001). The mean number of admissions was reduced from 3.2 (95% CI: 2.9-3.7) to 2.0 (95% CI: 1.6-2.4) (p < 0.001). Overall, 240 patients (73.6%) had reduced bed-days and 130 (39.9%) were not admitted while treated with clozapine. Moreover, the number of psychotropic co-medications was reduced from 4.5 defined daily doses (DDD) (25-75 percentiles: 2.4-8.2) to 3.9 DDD (25-75 percentiles: 2.4-6.1) (p = 0.045). Somatic hospital visits for intentional self-harm/overdose reduced significantly from 8.3% to 3.1% (p = 0.004). However, non-psychotropic co-medication use for medical conditions did not increase; 0.7 DDD (25-75 percentiles: 0.0-2.9) to 0.8 DDD (25-75 percentiles: 0.1-2.89) (p = 0.3). CONCLUSIONS Clozapine use for BD was associated with a significant and clinically relevant reduction in the number of bed-days, psychiatric admissions, psychotropic co-medications, and hospital contact for self-harm/overdose, without increased medical treatments. Clozapine seems to be an appropriate choice for treatment-resistant BD and should be investigated in randomized controlled trials.
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Affiliation(s)
- Jimmi Nielsen
- Unit for Psychiatric Research, Aalborg Psychiatric Hospital, Aarhus University Hospital, Aalborg, Denmark.
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Stark A, Scott J. A review of the use of clozapine levels to guide treatment and determine cause of death. Aust N Z J Psychiatry 2012; 46:816-25. [PMID: 22327098 DOI: 10.1177/0004867412438871] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To review the literature to examine the use of clozapine levels to (i) guide therapy and prevent toxicity in clinical care and (ii) determine cause of death in post-mortem examination of patients who were treated with clozapine. METHODS MEDLINE was searched in December 2010 using the following keywords: 'clozapine levels', 'clozapine and toxicity', 'clozapine and death', 'clozapine and mortality' and 'post-mortem redistribution'. Data was also collected from the 2010 MIMS Annual. RESULTS The literature reported significant variation in clozapine levels attained with any given dose, and considerable variability in the clinical response achieved at any given clozapine level. The lowest effective clozapine levels ranged from 250 to 550 µg/L, while the recommended upper limit to prevent toxicity varied from 600 to 2000 µg/L. There was minimal correlation between clozapine levels and side effects, with the exception of sedation, hypotension and seizure activity. The risk of seizures increased with plasma clozapine levels greater than 600 µg/L or rapid upward titration. In addition to prescribed dose, there are many factors that influence plasma clozapine levels. After death, the process of post-mortem drug redistribution resulted in 3.00 to 4.89 times increases in clozapine levels in central blood vessels and 1.5 fold increases in peripheral vessels compared to ante-mortem levels. CONCLUSIONS The exact range of clozapine levels that corresponds to toxicity remains unclear. However, levels between 350 µg/L and 1000 µg/L achieved with gradual upward titration are more likely to be effective and less likely to cause toxicity. Ongoing clozapine level monitoring is indicated, especially when (i) prescribing higher doses (> 600 mg/day) of clozapine, (ii) there has been a change in a patient's concomitant pharmacotherapy or cigarette use and (iii) there has been a suboptimal response to treatment. The use of post-mortem clozapine levels to determine clozapine toxicity as a cause of death is unreliable.
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Affiliation(s)
- Anne Stark
- Metro North Mental Health, Royal Brisbane and Women's Hospital, Herston, Australia
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Age and sex impact clozapine plasma concentrations in inpatients and outpatients with schizophrenia. Am J Geriatr Psychiatry 2012; 20:53-60. [PMID: 21422906 DOI: 10.1097/jgp.0b013e3182118318] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although clozapine is primarily used in a younger to mid-life population of patients with psychosis, there are limited data on the clinical pharmacology of clozapine later in life. The objective of this study was to assess the magnitude and variability of plasma concentrations of clozapine and norclozapine across the lifespan in a real-world clinical setting. DESIGN A population pharmacokinetic study using nonlinear mixed effect modeling (NONMEM). Age, sex, height, weight, and dosage formulation were covariates. SETTING Inpatients and outpatients at the Centre for Addiction and Mental Health, Toronto, from 2001 to 2007. PARTICIPANTS Patients ranging in ages from 11 to 79 with schizophrenia spectrum disorders and prescribed clozapine (Clozaril). MEASUREMENTS A total of 1142 plasma clozapine and norclozapine concentrations (2,284 concentration measurements) from 391 patients with schizophrenia spectrum disorder. RESULTS A one-compartment model with first-order absorption and elimination best described the data. The population predicted clearance of clozapine for females was 27.1 L/h (SE 11.1%) and 36.7 L/h (SE 9.7%) for males. For norclozapine, clearance in females was 48.6 L/h (SE 10.8%) and 63.1 L/h (SE 9.3%) in males. The only covariates with a significant effect on clearance were age and sex: clearance for both parent and metabolite decreased exponentially with age at least 39 years. CONCLUSIONS Decreased clearance of clozapine and norclozapine with age results in increased blood concentrations and, hence, the potential for adverse drug reactions. These findings have particular clinical relevance for the dosing and safety monitoring of clozapine in older adults, highlighting a need for increased vigilance.
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Lee SY, Park MH, Patkar AA, Pae CU. A retrospective comparison of BMI changes and the potential risk factors among schizophrenic inpatients treated with aripiprazole, olanzapine, quetiapine or risperidone. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:490-6. [PMID: 21146575 DOI: 10.1016/j.pnpbp.2010.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/03/2010] [Accepted: 12/03/2010] [Indexed: 11/15/2022]
Abstract
The objective of this study was to evaluate weight gain and its potential risk factors among different second generation antipsychotics (SGAs). The study was conducted for Korean inpatients with schizophrenia in a university hospital in Seoul, between Jan 2000 and Dec 2007. Data were collected by reviewing the medical records of the patients, who were prescribed to one of the SGAs among aripiprazole, olanzapine, quetiapine or risperidone. The changes of weight and body mass index (BMI); risk of clinically significant weight gain (>7% gain to initial weight) and their associations with various clinical characteristics of such patients were analyzed. Five hundred and eighty-eight (588) and 294 subjects treated with one of the four SGAs for a duration of 1 month and 2 months were included, respectively. Olanzapine showed significantly greater weight and BMI increase at month 1 (p=0.028 for weight; p=0.019 for BMI) and month 2 (p=0.032 for weight; p=0.029 for BMI) than others. Females showed greater BMI increase change (0.70±0.91 kg/m(2), p=0.008) and were also more likely to experience clinically significant weight gain (odd ratio=1.846, 95% CI=1.098 to 3.105, p=0.021) at month 1. Younger patients (<45 years old) had significantly greater weight and BMI increase at both months 1 and 2. Younger patients also showed greater risk for clinically significant weight gain at month 2 (odd odd ratio=2.567, 95% CI=1.196 to 5.508, p=0.016). Low baseline BMI (<25 kg/m(2)) was associated with greater weight gain at month 1 (1.92±2.29 kg, p<0.001) and month 2 (4.07±3.56 kg, p<0.001) and BMI increase at month 1 and month 2 (p<0.001 for both). Patients with low baseline BMI showed higher risk of clinically significant weight gain at both months 1 and 2 (p<0.001 for both). Olanzapine was shown to have higher metabolic risk than other SGAs in inpatients with schizophrenia. The individual's own clinical characteristics also exerted influence on weight gain effects of SGAs. Younger patients with lower baseline BMI were under greater risk of antipsychotic-induced weight gain. More studies are required to verify the role of gender on weight gain.
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Affiliation(s)
- Seung-Yup Lee
- Department of Psychiatry, Seoul St. Mary's Hospital, The Catholic University of Korea, College of Medicine, Seoul, Republic of Korea
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Abstract
Evidence suggests sex differences in schizophrenia reflect differences in both neurodevelopmental processes and social effects on disease risk and course. Male:female incidence approximates 1.4:1 but at older onset women predominate. Prevalence differences appear smaller. Men have poorer premorbid adjustment and present with worse negative and less depressive symptoms than women, which may explain their worse medium term outcome according to a range of measures. Substance abuse is a predominantly male activity in this group, as elsewhere. Findings of sex differences in brain morphology are inconsistent but occur in areas that normally show sexual dimorphism, implying that the same factors are important drivers of sex differences in both normal neurodevelopmental processes and those associated with schizophrenia. There are sex differences in antipsychotic responses but sex-specific endocrine effects on illness and response to antipsychotics are potentially complex. Oestrogen's role as an adjunctive medication is not yet clear due to methodological differences between the few randomized controlled trials. Services that are sensitive to differences in gender can better meet their patients' specific needs and potentially improve outcome.
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Affiliation(s)
- Kathryn M Abel
- Centre for Women's Mental Health, School of Community Based Medicine, University of Manchester, Oxford Road, Manchester, UK.
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Abstract
OBJECTIVE Optimum outcome for those with psychosis will necessarily involve treatment with antipsychotic medication. Unfortunately this medication is associated with a high rate of adverse effects and as a consequence non-adherence. Maximizing symptomatic relief whilst minimizing side effects is the aim of treatment. In order to do this adequately prescribers need to be aware of the significant differences between men and women in response to antipsychotic treatment. These differences are not simply biologically mediated; both physiological and sociocultural factors contribute. METHOD Findings from a variety of sources were used to summarize gender differences in antipsychotic treatment. RESULTS Pharmacokinetic and pharmacodynamic factors, the impact of reproductive phases in women and gender differences in antipsychotic prescription across the lifespan (from children and adolescents to the elderly) are discussed. Important ethnic and racial differences are also mentioned. CONCLUSION Women require less antipsychotic medication than men to achieve a better symptom response, but this is at the expense of a higher side effect burden, in particular hormonal and metabolic side effects. Children, adolescents and the elderly are at especially high risk of adverse reactions with antipsychotics. In order to optimize outcome in people with psychosis, prescribers should ensure that gender differences are taken into account.
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Affiliation(s)
- Shubulade Smith
- Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry at Kings College London, De Crespigny Park, London, UK.
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Suzuki T, Uchida H, Watanabe K, Kashima H. Factors associated with response to clozapine in schizophrenia: a review. PSYCHOPHARMACOLOGY BULLETIN 2011; 44:32-60. [PMID: 22506438 PMCID: PMC5044555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND Clozapine has been serving as the gold standard medication for patients with treatment-resistant schizophrenia who failed to respond to other antipsychotics. However, factors affecting response to this medication have not been comprehensively reviewed recently. METHODS In order to find factors associated with response to clozapine in schizophrenia, a literature search was conducted using PubMed through January 2011 with keywords of clozapine, response, and schizophrenia. Cross-referencing of relevant articles was also performed. Factors were arbitrarily classified into the following: demographic/clinical, oral dosage/pharmacokinetic, biochemical, (electro)physiological, genetic, imaging, and combinations. RESULTS A synthesis from 280 articles indicated that demographic and clinical variables such as high baseline symptoms and low premorbid functioning have not been particularly useful in predicting response to clozapine. Pharmacokinetic evidence points to a threshold clozapine level of 350 ng/ml but in a context of significant inter- as well as intra-individual variability. Pharmacokinetic perspectives appear to have more implication in special situations including poor response, suspected toxicity and nonadherence. A number of laboratory-based studies have reported on many potential candidates for response prediction to clozapine, however, reproducibility, specificity, robustness of the findings, as well as clinical feasibility and cost-effectiveness all pose a significant practical challenge, in relation with the fact that pathophysiological bases of treatment resistance in schizophrenia largely remain to be elucidated. CONCLUSIONS No unequivocal factors to clozapine response were found despite a relatively rich body of the literature, which calls for more works on this important topic. Clozapine level of 350 ng/ml appears to be useful in case of nonresponse.
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Affiliation(s)
- Takefumi Suzuki
- Keio University, School of Medicine, Department of Neuropsychiatry, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Bobo WV, Stovall JA, Knostman M, Koestner J, Shelton RC. Converting from brand-name to generic clozapine: A review of effectiveness and tolerability data. Am J Health Syst Pharm 2010; 67:27-37. [DOI: 10.2146/ajhp080595] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- William V. Bobo
- Department of Psychiatry, School of Medicine, Vanderbilt University, Nashville, TN
| | - Jeffrey A. Stovall
- Department of Psychiatry, School of Medicine, Vanderbilt University, Nashville, TN
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Clozapine exposure and the impact of smoking and gender: a population pharmacokinetic study. Ther Drug Monit 2009; 31:360-6. [PMID: 19349931 DOI: 10.1097/ftd.0b013e31819c7037] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The primary objective of this study was to evaluate the magnitude and variability of concentration exposure to clozapine and norclozapine in a real-world clinical setting, with a focus on smoking status, using population pharmacokinetic methodologies. A retrospective review of plasma clozapine and norclozapine concentrations taken from inpatients at the Centre for Addiction and Mental Health, Toronto, from 2001 to 2007 was conducted. A nonlinear mixed-effects model was developed using NONMEM, including age, gender, weight, smoking status, and dosage formulation as covariates. Pharmacokinetic parameters and interindividual and residual variabilities were estimated with 1- and 2-compartment models. A total of 519 plasma clozapine concentrations from 197 patients (138 males; mean +/- SD age, 38 +/- 13 years; schizophrenia spectrum disorder 98.2%) were included for the analysis. A 1-compartment model with first-order absorption and elimination best described the data. Apparent volume of distribution was fixed to a previously reported value in the literature of 7 L/kg.The population-predicted oral clearance of clozapine and norclozapine was 18.0 and 39.0 L/h, respectively; both the predicted clearance values vary nearly 6-fold (range, 9.18-59.06 and 16.29-97.84 L/h, respectively). For clozapine, smokers and males showed increased oral clearance by 6.0 and 4.5 L/h, respectively. For norclozapine, smokers and male gender were associated with an increased oral clearance of 11.3 and 7.6 L/h, respectively. The formulation of clozapine administered had an impact on the absorption rate with a Ka of 0.14/h for tablet and 10.3/h for the suspension form.The data suggest that smoking and male gender are associated with lower exposure to clozapine and norclozapine due to the higher oral clearance. These findings may account for some of the variability in clozapine exposure and have important implications for individualized drug dosing and therapeutic drug monitoring.
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Determination of pharmacokinetic properties of clozapine and norclozapine in Korean schizophrenia patients. Int Clin Psychopharmacol 2009; 24:139-44. [PMID: 19194306 DOI: 10.1097/yic.0b013e3283277627] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There is a wide interethnic variance in the pharmacokinetic profile of clozapine (CLZ), but the accumulated data are limited to some regional populations. In this study, we investigated the pharmacokinetic profile of CLZ in Korean patients and examined the association between serum CLZ parameters and clinical outcome. We assessed 78 Korean patients with schizophrenia who had been taking CLZ medication for more than 6 months. The patients were classified into three groups (good, moderate, and poor responders) according to their Clinical Global Impressions-Improvement scores. The serum concentrations of CLZ and norclozapine were 610.7+/-368.4 and 314.5+/-163.0 ng/ml (mean+/-SD), respectively, showing a large interindividual variation that was affected by dose, age, smoking habits, and sex by variable degrees. The pharmacokinetic profiles of Koreans were similar to those observed in Asians but quite different from those in Caucasians. Investigation on clinical responses revealed that the good or moderate responders clinically improved at a relatively low serum CLZ levels, whereas the poor responders showed less improvement despite the higher doses and serum levels. The metabolic ratio of the good responders was 0.65+/-0.20, higher than the poor responders (P=0.033). In this study, we identified a pharmacokinetic profile of CLZ in Korean schizophrenia patients and found a wide interindividual difference affected by various factors.
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Bahaoddini A, Farrashbandi H, Saadat M. Genetic Polymorphism of Glutathione S-transferase T1 (GSTT1) and QT-Interval in Schizophrenia Patients. J Mol Neurosci 2009; 38:173-7. [DOI: 10.1007/s12031-008-9160-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 10/31/2008] [Indexed: 02/02/2023]
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