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ABSTRACT: 9-Hydroxyrisperidone (9-OH-RIS) is an active metabolite of the antipsychotic drug risperidone (RIS). The total active moiety level, in other words the sum of the RIS and 9-OH-RIS serum levels, may be important for estimating the clinical effects of RIS treatment. However, there have been no consistent results reported regarding the relationship between cytochrome P450 (CYP) 2D6 or adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) variant alleles and 9-OH-RIS or total active moiety plasma levels. Seventy-four Japanese patients treated with RIS were examined in the present study. Steady-state plasma RIS and 9-OH-RIS were measured. The CYP2D6*5, CYP2D6*10, ABCB1 3435C>T, and ABCB1 2677G>T/A genotypes were detected. Multiple regression analysis showed that the dose-corrected plasma RIS levels were significantly correlated with the number of CYP2D6 variant alleles and ABCB1 3435C>T genotypes, whereas the 9-OH-RIS and total active moiety levels were significantly correlated with the ABCB1 3435C>T genotypes and with age. On the other hand, the ABCB1 2677G>T/A genotypes did not affect plasma RIS, 9-OH-RIS, or total active moiety levels. The ABCB1 3435C>T genetic polymorphism may predict plasma 9-OH-RIS and total active moiety levels.
Journal of clinical psychopharmacology 04/2013; · 5.09 Impact Factor
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ABSTRACT: OBJECTIVE: We examined sex differences in the effect of olanzapine (OLZ), risperidone (RIS), aripiprazole (ARP), or quetiapine (QTP) on mean corrected QT (QTc) intervals among 222 patients with schizophrenia. METHODS: Subjects were patients with schizophrenia who were treated with either OLZ (n = 69), RIS (n = 60), ARP (n = 62), or QTP (n = 31). Electrocardiographic measurements were conducted, and the QT interval was corrected using Bazett's correction formula. RESULTS: The mean QTc interval of the QTP group was significantly longer than that of the RIS group (p = 0.002) or ARP group (p = 0.029). The mean QTc interval of the OLZ group was also significantly longer than that of the RIS group (p = 0.006). In female participants, the difference in the mean QTc interval among the four second-generation antipsychotic (SGA) groups was statistically significant (p = 0.002), whereas in male patients, there was no significant difference in the mean QTc interval among the four SGA groups. Post hoc analyses showed that sex differences in QTc interval were observed only in OLZ treatment group (p = 0.007). CONCLUSION: To our knowledge, this is the first study to demonstrate sex differences in the effect of four SGAs on the QTc interval. Copyright © 2013 John Wiley & Sons, Ltd.
Human Psychopharmacology Clinical and Experimental 04/2013; · 2.48 Impact Factor
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ABSTRACT: OBJECTIVES: There have so far been few papers studying the metabolic syndrome (MetS) prevalence rate in Japanese patients with schizophrenia. We studied the MetS prevalence rate in Japanese controls and inpatients with schizophrenia and compared the prediction factors for the occurrence of MetS. METHODS: The subjects were 319 inpatients with schizophrenia and 154 controls. The predictive utilities of body mass index (BMI) and the individual components of MetS for MetS diagnosis were evaluated. RESULTS: The prevalence of MetS did not differ between schizophrenia and control subjects. Subjects with schizophrenia showed higher prevalences of the MetS criteria for high-density lipoprotein cholesterol (HDL) (p < 0.001) and waist circumference (WC) (p < 0.001). In subjects with schizophrenia, the predictive power was found to be highest for HDL, followed by WC, BMI, triglyceride, diastolic blood pressure (BP), systolic BP and fasting plasma glucose. However, in control subjects, the predictive power was found to be highest for triglyceride, followed by WC, systolic BP, BMI, HDL, diastolic BP and fasting plasma glucose. HDL was the component most predictive of MetS in subjects with schizophrenia treated with antipsychotics. CONCLUSION: Because, in normal clinical practice, it is difficult to obtain temporal measurements for all of the MetS criteria, measurement of HDL may be useful for predicting the MetS. Copyright © 2013 John Wiley & Sons, Ltd.
Human Psychopharmacology Clinical and Experimental 03/2013; · 2.48 Impact Factor
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ABSTRACT: Although second-generation antipsychotics (SGAs) are characterized by fewer prolactin (PRL)-related side effects compared with first-generation antipsychotics, the detailed effects of SGAs on the plasma PRL levels still remain unclear. We examined the differences in plasma PRL levels among 268 patients treated for schizophrenia with olanzapine (OLZ), risperidone (RIS), aripiprazole (ARP), quetiapine (QTP), or perospirone (PER). The participants had received antipsychotic monotherapy with stable doses of OLZ, RIS, ARP, QTP, or PER for ≥3weeks, and fasting blood samples were drawn to examine plasma PRL levels. The differences in median plasma PRL levels in all (P<0.001), male (P<0.001) and female patients (P<0.001) among the five SGA groups were statistically significant. A stepwise multiple regression analysis showed that ARP treatment was found to contribute to lower plasma PRL level, while female sex, RIS, OLZ and chlorpromazine equivalent dose were found to contribute to a higher plasma PRL level. The median value of plasma PRL level in the RIS group was twice as much compared with that in the OLZ group, although this was not statistically significant. In this study, OLZ had a considerable effect on plasma PRL level, similar to RIS, while PER did not affect plasma PRL levels, similar to QTP. Further studies are needed to clarify the differences in plasma PRL levels among SGAs.
Biological Psychiatry 01/2013; · 8.28 Impact Factor
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ABSTRACT: People with schizophrenia have higher rates of medical illness and mortality than the general population. Cardiovascular disease is a major contributor to premature death in patients with schizophrenia. There has been an increase literature discussing the high prevalence of dyslipidemia, which is one of risk factors for cardiovascular disease, induced by second generation antipsychotic agents. Depression is associated with increased risks of diabetes, hypertension, cardiovascular disease. However, those may not be secondary to the use of antidepressant agents. In order to reduce the risk of cardiovascular disease in patients with schizophrenia receiving antipsychotic agents, obtaining fasting lipid measurements at regular intervals is needed. Further investigations are needed to evaluate the effects of antidepressive agents on lipid profiles.
Current Atherosclerosis Reports 01/2013; 15(1):292. · 2.66 Impact Factor
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ABSTRACT: OBJECTIVES: There are few reports regarding quetiapine (QTP)-related QT prolongation. We examined the change in QT interval after switching from aripiprazole (ARP), olanzapine (OLZ), or risperidone (RIS) to QTP. METHODS: Twenty subjects treated with ARP, OLZ, or RIS were enrolled in the study. Following baseline assessments, which included QT interval and electrolytes, these three drugs were switched to QTP for each subject. The same parameters were evaluated following a switch to QTP. RESULTS: All 20 patients who had been treated with ARP, OLZ, or RIS were successfully switched to QTP. Significant increases were observed in the total mean corrected QT (QTc) interval after switching (p = 0.014). The coefficient of variation for the extent of change in QTc interval was 1.66. The mean QTc with ARP treatment was significantly increased after QTP treatment (p = 0.004). CONCLUSIONS: Quetiapine might have a greater effect on QTc interval than other second-generation antipsychotics. However, because there was a considerable variability in the extent of QTc prolongation after switch to QTP, further studies are required to clarify the effect of QTP on QTc interval. Copyright © 2012 John Wiley & Sons, Ltd.
Human Psychopharmacology Clinical and Experimental 11/2012; · 2.48 Impact Factor
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ABSTRACT: The development of impaired glucose tolerance induced by antipsychotics (APs) is of concern as a serious adverse effect of psychiatric drug therapy. However, the mechanism by which APs cause dysfunction of the glucose-insulin response is not fully understood. Recent studies have shown that patients treated with APs for schizophrenia were more likely to exhibit impaired glucose tolerance after a glucose load compared with healthy control subjects, even if fasting glucose levels were within the reference range. To explain these findings, we hypothesized that insulin secretion is increased in schizophrenic patients treated with AP, even those normal fasting glucose (NFG) levels. Therefore, oral glucose tolerance tests were conducted in 159 Japanese inpatients with AP-treated schizophrenia and in 90 healthy subjects without schizophrenia. Plasma glucose and serum insulin concentrations were measured before (0 minute) and at 30, 60, 90, and 120 minutes after the oral glucose load. Although insulin levels at 0 minute were similar in both groups of subjects, insulin levels were significantly higher in the patients treated with AP at all times after the glucose load than in the healthy subjects. In analyses of NFG subjects, insulin levels were significantly higher in the patients treated with AP compared with the healthy subjects at all times after glucose loading. Overall, we found that insulin secretion in response to a glucose load was significantly higher in the patients treated with AP, irrespective of NFG. These results suggest that APs affect the glucose-insulin response, which may lead to subclinical insulin resistance before the onset of overt glucose intolerance.
Journal of clinical psychopharmacology 11/2012; · 5.09 Impact Factor
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Psychiatry and Clinical Neurosciences 10/2012; 66(6):534-5. · 2.13 Impact Factor
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Psychiatry and Clinical Neurosciences 06/2012; 66(4):370-1. · 2.13 Impact Factor
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ABSTRACT: Antipsychotic-treated schizophrenia patients are susceptible to dyslipidemia. However, the results of previous studies of North American and UK populations including various races have been contradictory with regard to which lipid measure was the most affected in patients with schizophrenia taking antipsychotic agents. The aim of this study was to investigate the effect of schizophrenia patients receiving antipsychotic agents on each lipid measure in a Japanese population.
The samples included 136 control individuals and 157 patients with schizophrenia treated with antipsychotic agents. Age, gender distribution and body mass index (BMI) of the controls were matched with the patients.
The high-density lipoprotein cholesterol (HDL-cholesterol) levels were significantly lower in patients than in the control subjects (P<.001). However, there were no significant differences in either the low-density lipoprotein cholesterol (LDL-cholesterol) or triglyceride levels between the patient and control groups. We performed a multiple linear regression analysis, and schizophrenia receiving antipsychotics was an independent predictor of decreased HDL-cholesterol. An increased BMI, male gender and cigarette smoking were also major predictors of a decreased HDL-cholesterol level (r(2)=0.42, P<.001).
At least in Japanese with schizophrenia receiving antipsychotic agents, the HDL-cholesterol levels should be closely monitored in all patients, even those who are not obese or do not smoke, to decrease their risk of cardiovascular disease.
General hospital psychiatry 05/2012; 34(5):525-8. · 2.67 Impact Factor
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ABSTRACT: The underlying mechanism for second-generation antipsychotic (SGA)-related glucose-lipid metabolic dysfunction is not fully understood. Recent studies have suggested a possible impact of SGAs on endocrine regulation, especially on adipocytokines. We examined the effect of each SGA on various adipocytokines in normal fasting glucose (NFG) subjects.
The study population comprised 113 Japanese inpatients with schizophrenia who were treated with olanzapine, risperidone, or quetiapine, and 123 healthy control (CONT) volunteers. All of the subjects were diagnosed with NFG. Plasma concentration of adiponectin, leptin, tumor necrosis factor α, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were compared between the SGA and CONT groups.
Second-generation antipsychotic subjects had significantly higher leptin levels in comparison to the CONT subjects. The plasma concentration of adiponectin, total cholesterol, and high-density lipoprotein cholesterol in the SGA subjects were significantly lower than those in the CONT subjects. There were no significant differences in tumor necrosis factor α, triglyceride, and low-density lipoprotein cholesterol levels between the 2 groups. In a stepwise multiple regression analysis, olanzapine was found to be a factor that contributed to decreased adiponectin levels, and the CONT subjects were detected to be a factor associated with lower leptin levels.
The present study indicates the possibility that the administration of SGAs may affect adipocytokines in the NFG stage, excluding the impaired fasting glucose group, which is in the transition stage into diabetes mellitus.
Journal of clinical psychopharmacology 04/2012; 32(3):390-3. · 5.09 Impact Factor
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Psychiatry and Clinical Neurosciences 04/2012; 66(3):244. · 2.13 Impact Factor
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ABSTRACT: The sum of the serum levels of risperidone (RIS) and 9-hydroxyrisperidone (9-OH-RIS), which is the active moiety serum level, could be important for estimating the clinical effects of RIS. However, there have been no consistent results reported about the relationship between cytochrome P450 (CYP) 2D6*10 allele and plasma 9-OH-RIS or active moiety levels. We investigated the effect of the number of CYP2D6*10 alleles on steady-state plasma RIS, 9-OH-RIS, and active moiety levels in Japanese patients.
Steady-state plasma RIS, 9-OH-RIS, and active moiety levels were measured in 64 patients treated with an average dosage of 4.6 mg/day.
The number of CYP2D6*10 alleles significantly affected dose-corrected plasma RIS levels (p = 0.001), and the median concentrations in ng/ml/mg were 0.94 (0 allele) vs. 1.73 (1 allele) vs. 3.05 (2 alleles). The number of CYP2D6*10 alleles did not affect plasma 9-OH-RIS or active moiety levels.
The present study shows that the number of CYP2D6*10 alleles affected plasma RIS levels but not plasma 9-OH-RIS and plasma active moiety levels. Because the plasma active moiety levels can influence antipsychotic effects or side effects, the genetic screening of the CYP2D6*10 allele for RIS in Asian populations may not be clinically important.
Human Psychopharmacology Clinical and Experimental 01/2012; 27(1):43-6. · 2.48 Impact Factor
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ABSTRACT: Most antipsychotic agents can cause QT prolongation, which causes torsades de pointes. The QT interval in healthy subjects is longer during nighttime than during daytime. The QT interval of patients treated with antipsychotics may be prolonged during nighttime, and the effects of antipsychotics on the QT interval may differ between antipsychotics. This study investigated the circadian dynamics of the QT interval in patients treated with antipsychotics and healthy controls, using a 24-hour Holter electrocardiogram in a clinical setting. Sixty-six patients with a diagnosis of schizophrenia that were treated with risperidone or olanzapine and 40 healthy volunteers were enrolled. The QT intervals were corrected using the Fridericia formula (QTcF = QT / RR). Mean ± SD nighttime QTcFs were 411.6 ± 29.0, 395.9 ± 21.2, and 387.8 ± 19.0 milliseconds (ms) in the risperidone, olanzapine, and control groups, respectively. The mean daytime QTcFs were 397.7 ± 23.4, 392.4 ± 18.9, and 382.6 ± 17.3 ms, respectively. The mean nighttime QTcF of the risperidone group was significantly longer than that of the olanzapine and control groups, although there was no significant difference in the mean daytime QTcF between the risperidone and olanzapine groups. The current study used 24-hour Holter electrocardiograms to reveal significantly longer QT intervals in the risperidone group especially during nighttime. In clinical practices, evaluations of the QT interval have been conducted over short periods in the daytime, but it is believed that such methods may not be able to fully elucidate the effects of antipsychotics on the QT interval.
Journal of clinical psychopharmacology 12/2011; 32(1):18-22. · 5.09 Impact Factor
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ABSTRACT: A dose-dependent increase in risk of sudden cardiac death for the antipsychotic drug risperidone was reported. However, few reports have so far addressed QT prolongation associated with the use of risperidone or its major active metabolite, which is also used as a separate antipsychotic drug, paliperidone.
The present study evaluated associations between risperidone metabolism and QT interval in 61 psychiatric patients who had been receiving risperidone for ≥4 weeks at an average dosage of 4.7 mg/day. Plasma risperidone and paliperidone levels were measured and electrocardiographic measurements were also obtained.
There was no correlation between risperidone dosage and QTc or plasma risperidone levels and QTc. However, there was a significant positive correlation between plasma paliperidone levels and QTc (r = 0.361; p = 0.004). There was no correlation between age and dose-corrected plasma risperidone levels or between age and QTc. There was a significant positive correlation between age and dose-corrected plasma paliperidone levels (r = 0.290; p = 0.023).
Clinically, paliperidone is considered to play a more important role in QT prolongation than risperidone.
Human Psychopharmacology Clinical and Experimental 12/2011; 27(1):39-42. · 2.48 Impact Factor
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ABSTRACT: Objectives
There have been few reports regarding olanzapine (OLZ)-related QT prolongation and hyperprolactinemia. This study evaluated the dose-dependent effect of OLZ on QT interval and plasma prolactin (PRL) level in a single sample of patients with schizophrenia.Methods
Twenty-six subjects treated with varying starting doses of OLZ were enrolled in the study. Following baseline assessments, which included completion of the Brief Psychiatric Rating Scale (BPRS), measurements of Body Mass Index (BMI), QT interval, electrolytes, fasting plasma glucose, PRL, hemoglobin A1c (HbA1c), total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), and low density lipoprotein (LDL), the dose of OLZ was increased for each subject. The same parameters were evaluated following the increased dose treatment.ResultsA significant decrease was observed in BPRS score (p = 0.01) following treatment with an increased dose of OLZ. Significant increases were observed in BMI (p = 0.032), QTc (p = 0.031), and plasma PRL level (p = 0.028). The mean values of electrolytes, fasting plasma glucose, HbA1c, TC, TG, HDL and LDL treatment were unchanged by the switch to increased-dose OLZ treatment.Conclusion
We have demonstrated the dose-dependent effect of OLZ on the QT interval and the plasma PRL level of patients with schizophrenia. Copyright © 2011 John Wiley & Sons, Ltd.
Human Psychopharmacology Clinical and Experimental 08/2011; 26(6):440 - 443. · 2.48 Impact Factor
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Journal of clinical psychopharmacology 08/2011; 31(4):526-8. · 5.09 Impact Factor
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ABSTRACT: The CYP2D6 enzyme is a capacity-limited high-affinity drug elimination pathway that metabolizes numerous psychiatric medicines. The capacity-limited nature of this enzyme suggests that drug dose may serve as an important factor that influence genotype-phenotype associations. However, dose dependency of CYP2D6 genotype contributions to drug elimination, and its interaction with environmental factors (e.g., smoking) did not receive adequate attention in translational study designs. Fluvoxamine is a selective serotonin reuptake inhibitor antidepressant. Fluvoxamine concentration is one of the factors previously linked to clinical remission in moderate to severe depression. We investigated the joint effect of smoking (an inducer of CYP1A2) and CYP2D6 genotype on interindividual variability in fluvoxamine steady-state concentration. Fluvoxamine concentration was measured in 87 patients treated with 50, 100, 150 or 200 mg/d. While CYP2D6 genotype significantly influenced fluvoxamine concentration in all four dose groups (p < 0.05), the percentage variance explained (R²) by CYP2D6 decreased as the dose of fluvoxamine increased. Smoking status (nonsmokers vs. smoking 20 or more cigarettes/d) significantly affected fluvoxamine concentration in the 50 mg/d group only (p = 0.005). Together, CYP2D6 genotype and smoking status explained 23% of the variance in fluvoxamine concentration but only at the low 50 mg/d dose group. These findings contribute to evidence-based and personalized choice of fluvoxamine dose using smoking status and CYP2D6 genetic variation. Additionally, these data lend evidence for drug dose as an important variable in translational pharmacogenetic study design and pharmaceutical phenotype associations with capacity-limited drug metabolism pathways such as CYP2D6.
Journal of Psychopharmacology 07/2011; 25(7):908-14. · 3.04 Impact Factor
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ABSTRACT: We examined whether discontinuation and the responses to fluvoxamine (FLV) administration could predict the subsequent discontinuation and the responses to paroxetine (PRX) in patients with depression.
The subjects comprised 106 outpatients who were diagnosed with depression, and clinical evaluation was conducted every 2 weeks. Patients who discontinued FLV because of side effects or did not achieve remission with 200 mg/day of FLV, the drug was switched to PRX. The maximum dose of PRX was 40 mg/day.
Among 10 patients who discontinued FLV, PRX was also discontinued in one patient. Of 33 patients without remission on FLV, PRX was discontinued because of side effects in two patients. There was no statistical difference in the discontinuation rates between the two groups. Four of 10 patients who discontinued FLV achieved remission, while nine of 33 patients without remission with FLV achieved remission with PRX. The remission rate was not significantly different between the two groups.
Discontinuation and the responses related to FLV could not serve as a predictor for the subsequent discontinuation and the responses related to PRX.
Human Psychopharmacology Clinical and Experimental 11/2010; 25(7-8):525-9. · 2.48 Impact Factor
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ABSTRACT: Risperidone (RIS) has the highest propensity to elevate plasma prolactin (PRL) levels. While the active metabolite 9-hydroxy-risperidone (9-OH-RIS) plays a predominant role in the efficacy and side effects of RIS, the mechanistic details are still poorly understood. The present study evaluated the gender differences in the relationship between plasma levels of RIS or 9-OH-RIS and PRL.
Twenty-one male and 19 female subjects treated with RIS were enrolled in the present series. All patients had been receiving RIS for at least 4 weeks at an average dosage of 4.7 mg/day. Plasma RIS, 9-OH-RIS and PRL levels were measured.
In the male patients, there was no correlation between the RIS dosage and plasma PRL levels, between plasma RIS levels and PRL levels, or between the plasma 9-OH-RIS levels and PRL levels. In the female patients, there was a significant positive correlation between the plasma 9-OH-RIS levels and PRL levels (rs=0.456, p=0.049). There was a trend toward a significant positive correlation between the RIS dosage and plasma PRL levels. There was no correlation between the plasma RIS levels and PRL levels.
9-OH-RIS is considered to play a more important role in PRL elevation than RIS, and a gender difference exists in the effect of 9-OH-RIS on PRL level.
Progress in Neuro-Psychopharmacology and Biological Psychiatry 10/2010; 34(7):1266-8. · 3.25 Impact Factor
