Adjunctive use of reboxetine in schizophrenia

Selective noradrenaline reuptake inhibitors for schizophrenia

BACKGROUND

Schizophrenia is frequently a chronic and disabling illness with a heterogeneous range of symptoms. The positive symptoms usually respond to antipsychotics but the cognitive and negative symptoms of schizophrenia are difficult to treat with conventional antipsychotics and significantly impact on quality of life and social outcomes. Selective noradrenaline reuptake inhibitors (NRIs) increase prefrontal dopamine and noradrenaline levels without significantly affecting subcortical dopamine levels, making them an attractive candidate for treating cognitive and negative symptoms.

OBJECTIVES

To investigate the effects of selective noradrenaline reuptake inhibitors (NRIs), compared with a placebo or control treatment, for people with schizophrenia.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Trials Register (up to 7 February 2017) which is based on regular searches of MEDLINE, Embase, CINAHL, BIOSIS, AMED, PubMed, PsycINFO, and registries of clinical trials. There are no language, date, document type, or publication status limitation for inclusion of records into the register. We inspected references of all included studies for further relevant studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing NRIs with either a control treatment or placebo for people with schizophrenia or related disorders (such as schizoaffective disorder) by any means of diagnosis. We included trials that met our selection criteria and provided useable information.

DATA COLLECTION AND ANALYSIS

We independently inspected all citations from searches, identified relevant abstracts, and independently extracted data from all included studies. For binary data we calculated risk ratio (RR), for continuous data we calculated mean difference (MD), and for cognitive outcomes we derived standardised mean difference (SMD) effect sizes, all with 95% confidence intervals (CI) and using a random-effects model. We assessed risk of bias for the included studies and used the GRADE approach to produce a 'Summary of findings' table which included our prespecified main outcomes of interest.

MAIN RESULTS

Searching identified 113 records. We obtained the full text of 48 of these records for closer inspection. Sixteen trials, randomising a total of 919 participants are included. The majority of trials included adults with schizophrenia or similar illness who were inpatients, and while they were poorly characterised, most appeared to include patients with a chronic presentation. The intervention NRI in nine of the 16 trials was reboxetine, with atomoxetine and viloxazine used in the remaining trials. 14 trials compared NRIs with placebo. Only two trials provided data to compare NRIs against an active control and both compared reboxetine to citalopram but at 4 weeks and 24 weeks respectively so they could not be combined in a meta-analysis.One trial was described as 'open' and we considered it to be at high risk of bias for randomisation and blinding, three trials were at high risk of bias for attrition, six for reporting, and two for other sources of bias. Our main outcomes of interest were significant response or improvement in positive/negative mental state, global state and cognitive functioning, average cognitive functioning scores, significant response or improvement in quality of life and incidence of nausea. All data for main outcomes were short term.NRIs versus placeboMental state results showed significantly greater rates of improvement in negative symptoms scores (1 RCT, n = 50; RR 3.17, 95% CI 1.52 to 6.58; very low quality evidence) with NRIs on the PANSS negative. No data were reported for significant response or improvement in positive symptoms, but average endpoint PANSS positive scores were available and showed no difference between NRIs and placebo (5 RCTs, n = 294; MD -0.16, 95% CI -0.96 to 0.63; low-quality evidence). Improvement in clinical global status was similar between groups (1 RCT, n = 28; RR 0.99, 95% CI 0.45 to 2.20; very low quality evidence). Significant response or improvement in cognitive functioning data were not reported. Average composite cognitive scores showed no difference between NRIs and placebo (4 RCTs, n = 180; SMD 0.04, 95% CI -0.28 to 0.36; low-quality evidence). Significant response or improvement in quality of life data were not reported, however average endpoint scores from the GQOLI-74 were reported. Those receiving NRIs had better quality of life scores compared to placebo (1 RCT, n = 114; MD 9.36, 95% CI 7.89 to 10.83; very low quality evidence). All-cause withdrawals did not differ between the treatment groups (8 RCTs, n = 401, RR 0.94 95% CI 0.63 to 1.39; moderate-quality evidence). Rates of nausea were not greater with NRIs (3 RCTs, n = 176; RR 0.49, 95% CI 0.10 to 2.41; low-quality evidence).

AUTHORS' CONCLUSIONS

Our results provide tentative very low quality evidence that compared to placebo, NRIs (specifically reboxetine) may have a benefit on the negative symptoms of schizophrenia. Limited evidence also suggests that NRIs have no effect on the positive symptoms of schizophrenia or cognitive functioning. NRIs appear generally well tolerated with no real differences in adverse effects such as nausea noted between NRIs and placebo. However, these results are based on short-term follow-up and are poor quality - there is need for more good-quality evidence. A large RCT of reboxetine over a longer period of time, focusing specifically on negative and cognitive symptoms as well as more detailed and comprehensive reporting of outcomes, including adverse events, is required.

Amelioration of deficit syndrome of schizophrenia by norepinephrine reuptake inhibitor

OBJECTIVE

Negative symptoms are a significant barrier to successful functional outcome and recovery in individuals with schizophrenia and their management is not unproblematic. Reboxetine is a norepinephrine reuptake inhibitor (NRI). Previous studies regarding the useful effects of reboxetine on deficit symptoms of schizophrenia have resulted in inconsistent results. The present study therefore evaluated the effectiveness of reboxetine as an adjunctive treatment in a group of schizophrenic patients with prominent negative symptoms.

METHOD

A total of 50 male inpatients meeting diagnosis of schizophrenia entered into a 12-week parallel group, double-blind study for random assignment to reboxetine (n = 25 patients) or placebo (n = 25 patients). The inclusion criterion, in addition to the diagnosis of schizophrenia, was the existence of obvious negative symptoms for a duration of at least 2 years. The Scale for Assessment of Negative Symptoms (SANS) was used as the primary outcome measure. The Scale for Assessment of Positive Symptoms (SAPS), Simpson Angus Scale (SAS), Hamilton Rating Scale for Depression (HAM-D) and Mini-Mental Status Examination (MMSE) were used for comparison of the intervening parameters in this study.

RESULTS

According to the findings, 76% of patients in the target group showed some positive response to reboxetine compared with 24% in the control group (p < 0.01). The mean total score of SANS in the reboxetine group decreased significantly from 79.94 ± 1.20 to 74.23 ± 4.07 (p < 0.0001) at the end of the study; such an improvement was not significant in the placebo group with a decrease from 80.42 ± 2.46 to 79.08 ± 5.83 (p < 0.29). Changes of SAPS were insignificant in both groups. Effect size analysis for changes of SANS at the end of assessment indicated a large improvement with reboxetine (Cohen's d = 2.91).

CONCLUSION

Reboxetine, as an adjuvant to haloperidol, may have a helpful effect on the deficit syndrome of schizophrenia.

Relationship between Antidepressant Prescription Rates and Features of Schizophrenic Patients and Its Outcome in Schizophrenia Treatment

INTRODUCTION

Comorbid depression in schizophrenia is associated with poor outcome, increased risk of relapse and a high rate of suicide. Identification of depressive symptoms and their appropriate treatment is crucial for depressed schizophrenic patients. The aim of this study is to investigate the rates of antidepressant prescription and their outcomes.

METHODS

The records of the schizophrenic outpatients, who were consulted at Psychosis Unit of Psychiatry Department between January 2007 and September 2012, were evaluated retrospectively. Enrolled schizophrenic patients' antidepressant medications were at their minimal effective doses and effective duration.

RESULTS

The present study demonstrates that 39 of the 101 patients during their follow-ups were prescribed antidepressants. The mean follow-up period was 6.3 (±4.2) years; the mean age at onset was 22 (±6.5) years; the mean duration of illness was 14.7 (±7.3) years and the mean number of psychotic exacerbation was 5 (±3.7). The most prescribed antidepressants were; sertraline (36.9%), venlefaxine (23.8%) and essitalopram (20.2%). SSRI's were prescribed 57 (73.1%), where as SNRI's 21 times (26.9%). There was no significant difference between SSRI (78.6%) and SNRI (21.4%) treatments in terms of psychotic exacerbation under antidepressant medication. Full remission of depressive symptoms was achieved in 21 patients (53.8%). Remission rates were significantly higher (p<0.01) in SNRI treated depressed schizophrenic patients (85.7%) compared to SSRI treated patients (50.9%). In 8 of the 39 patients (20.5%) antidepressant treatment was terminated due to side effects.

CONCLUSION

This study demonstrates that SSRI's were more often prescribed compared to other classes of antidepressants in emerging depressive symptoms in schizophrenic patients despite full remission with SNRI's is more common. There was no significant difference between SSRI and SNRI treatment in terms of psychotic exacerbation.

Reboxetine adjuvant therapy in patients with schizophrenia showing a suboptimal response to clozapine: a 12-week, open-label, pilot study

The present 12-week open-label uncontrolled trial was aimed to explore the efficacy of reboxetine add-on pharmacotherapy on clinical symptoms and cognitive functioning in 15 patients with schizophrenia with suboptimal response (mean [SD] Brief Psychiatric Rating Scale baseline total score, 32.2 [5.4]) despite receiving clozapine monotherapy at the highest tolerated dosage. The results obtained evidenced that reboxetine at a dosage of 4 mg/d mildly reduced only depressive symptoms (Calgary Depression Scale for Schizophrenia: P = 0.035, Cohen d = 0.7), whereas worsening of performances on phonemic fluency (P = 0.012, Cohen d = 0.5) was observed. After Bonferroni correction, changes at the Calgary Depression Scale for Schizophrenia and at the Verbal Fluency Task were not further confirmed.The results obtained indicate that reboxetine seemed to be scarcely effective for reducing clinical symptoms in patients with schizophrenia who have had an incomplete clinical response to clozapine. Regarding cognitive functioning, in our sample, a trend to experience cognitive impairment in the examined domains was observed, as confirmed by a mild worsening of performances on cognitive tasks.Schizophrenia is a heterogeneous disorder with regard to pathophysiology; therefore, data reflecting the mean response of a sample of patients may fail to reveal therapeutic effects. More research is needed to better identify subgroups of patients with peculiar features, which may account for responsivity to experimental medications and augmentation strategies.

Efficacy and safety of noradrenalin reuptake inhibitor augmentation therapy for schizophrenia: a meta-analysis of double-blind randomized placebo-controlled trials

BACKGROUND

We performed an updated meta-analysis of noradrenalin reuptake inhibitor (NRI) augmentation therapy in patients with schizophrenia treated with antipsychotics based on a previous meta-analysis (Singh et al.).

METHODS

PubMed, Cochrane Library databases, and PsycINFO citations were searched from their inception to June 10, 2013 without language restrictions. We conducted a systematic review and meta-analysis of individual patient data from randomized controlled trials comparing NRI augmentation therapy with placebo. The outcome measure for efficacy was the psychopathology of schizophrenia and the measures for safety were discontinuation rate and several side effects. We used standardized mean differences (SMD) to estimate treatment effects for continuous variables, and risk ratios (RR) for dichotomous variables, with their 95% confidence intervals (CIs). A random-effects model was used.

RESULTS

Nine studies (4 atomoxetine studies, 3 reboxetine studies, 1 reboxetine-betahistine combination study and 1 mazindol study, total n=298) were identified. No statistically significant effects of NRI augmentation therapy on overall (p=0.90), positive (p=0.81), and negative (p=0.89) symptoms were found. NRI augmentation therapy was marginally superior to placebo for efficacy of depressive symptoms (SMD=-1.08, p=0.05). Dropout due to all-cause (p=0.70), inefficacy (p=0.64), or adverse events (p=0.18) was similar in both groups. NRI augmentation therapy showed a significantly lower increase or larger reduction in body weight than placebo (SMD=-0.47, p=0.03). Reboxetine augmentation was associated with less weight gain that placebo in antipsychotic treated schizophrenia patients (SMD=-0.78, p=0.0001).

CONCLUSION

NRIs may exert an effect on depressive symptoms, and seem to be well-tolerated treatments.

No effects of antidepressants on negative symptoms in schizophrenia

Negative symptoms are common in schizophrenia, but often difficult to differentiate from depression. They are associated with long-term impairment and do not respond well to current treatment approaches. Even though antidepressants are commonly prescribed in schizophrenia, their beneficial effect is still under debate. In the present study, we aimed to investigate the effect of serotonergic versus noradrenergic antidepressant add-on therapy on negative symptoms in schizophrenia. Fifty-eight patients with schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and with predominant negative symptoms were randomized in a double-blind design to add-on treatment with citalopram, reboxetine, or placebo for 4 weeks. Analysis of covariance with repeated-measures design was used to compare improvement between treatment groups in scores of the Positive and Negative Syndrome Scale and the Hamilton Rating Scale for Depression. A χ² test was used to compare responder rates between treatment groups. Repeated-measures analysis of covariance revealed no differences between treatment groups over time (treatment × time, not statistically significant) for Positive and Negative Syndrome Scale subscales. Although a subgroup analysis in subjects fulfilling the criteria for minor depression was suggestive of higher responder rates in the citalopram group compared with reboxetine, the results did not reach significance level. Our findings do not support a beneficial effect of adjunctive antidepressant treatment on negative symptoms in schizophrenia. However, depressive symptoms are reduced in patients with minor depression by citalopram but not reboxetine, which is in line with previous findings.

Role of concomitant inhibition of the norepinephrine transporter for the antipsychotic effect of quetiapine

Quetiapine alleviates both positive and negative symptoms as well as certain cognitive impairments in schizophrenia despite a low D2 receptor occupancy and may also be used as monotherapy in bipolar and major depressive disorder. The mechanisms underlying the broad clinical utility of quetiapine remain to be clarified, but may be related to the potent inhibition of the norepinephrine transporter (NET) by norquetiapine, the major metabolite of quetiapine in humans. Since norquetiapine is not formed in rodents we here investigated in rats whether NET-inhibition may, in principle, contribute to the clinical effectiveness of quetiapine and allow for its low D2 receptor occupancy, by combining quetiapine with the selective NET-inhibitor reboxetine. Antipsychotic-like activity was assessed using the conditioned avoidance response (CAR) test, dopamine output in the medial prefrontal cortex (mPFC) and the nucleus accumbens was measured using in vivo microdialysis, and NMDA receptor-mediated transmission was measured using intracellular electrophysiological recordings in pyramidal cells of the mPFC in vitro. Adjunct reboxetine potentiated the suppression of CAR by quetiapine. Moreover, concomitant administration of quetiapine and reboxetine resulted in a synergistic increase in cortical, but not accumbal, dopamine output. The combination of low, clinically relevant concentrations of quetiapine (60 nM) and reboxetine (20 nM) markedly facilitated cortical NMDA receptor-mediated transmission in contrast to either drug alone, an effect that could be inhibited by the D₁ receptor antagonist SCH23390. We conclude that concomitant NET-inhibition by norquetiapine may contribute to the overall antipsychotic effectiveness of quetiapine in spite of its relatively low level of D₂ occupancy.

Reboxetine enhances the olanzapine-induced antipsychotic-like effect, cortical dopamine outflow and NMDA receptor-mediated transmission

Preclinical data have shown that addition of the selective norepinephrine transporter (NET) inhibitor reboxetine increases the antipsychotic-like effect of the D(2/3) antagonist raclopride and, in parallel, enhances cortical dopamine output. Subsequent clinical results suggested that adding reboxetine to stable treatments with various antipsychotic drugs (APDs) may improve positive, negative and depressive symptoms in schizophrenia. In this study, we investigated in rats the effects of adding reboxetine to the second-generation APD olanzapine on: (i) antipsychotic efficacy, using the conditioned avoidance response (CAR) test, (ii) extrapyramidal side effect (EPS) liability, using a catalepsy test, (iii) dopamine efflux in the medial prefrontal cortex and the nucleus accumbens, using in vivo microdialysis in freely moving animals and (iv) cortical N-methyl-D-aspartate (NMDA) receptor-mediated transmission, using intracellular electrophysiological recording in vitro. Reboxetine (6 mg/kg) enhanced the suppression of CAR induced by a suboptimal dose (1.25 mg/kg), but not an optimal (2.5 mg/kg) dose of olanzapine without any concomitant catalepsy. Addition of reboxetine to the low dose of olanzapine also markedly increased cortical dopamine outflow and facilitated prefrontal NMDA receptor-mediated transmission. Our data suggest that adjunctive treatment with a NET inhibitor may enhance the therapeutic effect of low-dose olanzapine in schizophrenia without increasing EPS liability and add an antidepressant action, thus in principle allowing for a dose reduction of olanzapine with a concomitant reduction of dose-related side effects, such as EPS and weight gain.

Duloxetine for major depressive episodes in the course of psychotic disorders: an observational clinical trial

Patients with psychotic disorders often suffer from intercurrent major depressive episodes (MDE). Case reports suggested successful antidepressive treatment with duloxetine, a selective dual reuptake inhibitor of serotonin and norepinephrine. We initiated this open prospective clinical trial to evaluate efficacy, safety and tolerability of this approach. Patients with a psychotic lifetime diagnosis suffering from mildly severe MDE were treated with duloxetine over a period of 6 weeks. We evaluated effects on mood, monitored the psychotic psychopathology and assessed side effects, basal clinical and pharmacological parameters. Twenty patients were included and experienced a significant improvement of their MDE during the observation period (Calgary Depression Scale for Schizophrenia and Hamilton Depression Scale). Psychotic positive symptoms remained stably absent, while negative syndrome and global psychopathology considerably improved (Positive and Negative Syndrome Scale). In general, the treatment was well tolerated, serum prolactin levels stayed unchanged, but pharmacokinetic interactions with a number of antipsychotic agents were observed. This open prospective evaluation showed antidepressive efficacy of duloxetine in patients with co-morbid psychotic disorders. With regard to the psychotic disorder, the treatment appears to be safe and well tolerable. Further investigations should involve a randomized control group.