Patterns of clozapine prescribing in a mental health service in New Zealand

Comparative Study of the Efficacy and Side Effects of Brand-Name and Generic Clozapine for Long-Term Maintenance Treatment Among Korean Patients With Schizophrenia: A Retrospective Naturalistic Mirror-Image Study

OBJECTIVE

Clozapine is considered the most reliable drug for treatment-resistant schizophrenia. In 2014, a generic formulation of clozapine (Clzapine) was introduced in Korea. This study was performed to provide clinical information regarding the use of clozapine and to compare efficacy and tolerability when converting from the brand-name formulation (Clozaril) to the generic formulation during longterm maintenance treatment among Korean patients with schizophrenia.

METHODS

This mirror-image study retrospectively investigated the electronic medical records of patients who had switched from Clozaril to Clzapine with a ≥1-year duration for each formulation. Clinical data were collected, including information regarding clozapine use, psychiatric hospitalization, co-medications, and blood test findings. Data before and after the switch were compared using paired t-tests.

RESULTS

Among 332 patients, the mean 1-year dosages were 233.32±149.35 mg/day for Clozaril and 217.36±136.66 mg/day for Clzapine. The mean clozapine concentration-to-dose ratios were similar before and after the switch (Clozaril, 1.33±0.68; Clzapine, 1.26±0.80). Switching from Clozaril to Clzapine resulted in no significant differences in the hospitalization rate, hospitalization duration, or laboratory findings (liver function parameters, serum cholesterol level, and serum glucose level). Equivalent doses of co-prescribed antidepressants were decreased, but concomitant medications otherwise showed no significant differences.

CONCLUSION

Clinical efficacy and tolerability appear comparable when switching to Clzapine during clozapine maintenance treatment. This study offers descriptive real-world clinical insights into clozapine maintenance treatment in Korea, thereby providing patients with more treatment options and contributing to the development of maintenance guidelines tailored to the Korean population.

Long-term outcomes of delayed clozapine initiation in treatment-resistant schizophrenia: a multicenter retrospective cohort study

BACKGROUND

Clozapine is the only antipsychotic medication with proven efficacy against treatment-resistant schizophrenia. This multicenter retrospective cohort study aimed to evaluate the impact of a delay in clozapine initiation on long-term outcomes.

METHODS

Patients who initiated clozapine treatment between July 2009 and December 2018 were included in this study. According to the length of time from the diagnosis of schizophrenia to clozapine initiation, the patients were categorized into one of three groups: early (≤ 9 years), intermediate (10-19 years), and late (≥ 20 years) initiation. The endpoints were psychiatric rehospitalization and all-cause clozapine discontinuation within 3 years. Hazard ratios (HR) and 95% confidence interval (CI) were estimated using the Fine and Gray method or the Cox proportional hazards model.

RESULTS

The incidence rates of rehospitalization within three years, according to the cumulative incidence function, were 32.3% for early, 29.7% for intermediate, and 62.2% for late initiation, respectively. Late initiation had a significantly higher risk of psychiatric rehospitalization than early initiation (HR, 2.94; 95% CI, 1.01- 8.55; P = 0.016 by the Gray's test). The risk of psychiatric rehospitalization was not significantly different between the early and intermediate initiation groups. The incidence rate of all-cause clozapine discontinuation within three years using the Kaplan-Meier method was 13.0% for early, 10.6% for intermediate, and 20.1% for late initiation. The risk of all-cause clozapine discontinuation was not significantly among the groups. The late initiation group had more patients discontinuing because of death due to physical diseases than the other groups.

CONCLUSIONS

The study suggests that clozapine should be initiated promptly in patients with treatment-resistant schizophrenia to prevent psychiatric rehospitalization during long-term treatment. Further prospective studies with appropriate consideration of confounding factors and large sample sizes are needed to strengthen the evidence.

Dopamine supersensitivity psychosis and delay of clozapine treatment in patients with treatment-resistant schizophrenia

Both the underutilization of clozapine and treatment resistance of patients to clozapine are serious problems worldwide. Identifying clinical markers predicting response to clozapine would help clinicians more effectively utilize clozapine treatment. The present study retrospectively assessed dopamine supersensitivity psychosis (DSP) in addition to other measures such as age at disease onset and delay of clozapine introduction for a total of 47 treatment-resistant schizophrenia (TRS) patients. The response to clozapine was judged with CGI-C at 1 and 2 years from clozapine introduction. Results revealed that the DSP group tended to have a longer delay between designation of TRS and introduction of clozapine and continued to have slightly more severe psychopathology after treatment with clozapine, showing only slight improvement. The logistic regression analysis showed that the age at disease onset was the only significant indicator, predicting responsiveness to clozapine: patients with an onset age <20 years had a significantly better response to clozapine than patients with an onset age ≥20 years. The present study suggests that DSP might be related to a longer delay in clozapine introduction and the persistence of refractory symptoms despite clozapine treatment, whereas early age of disease onset might be related to a better response to clozapine.

Socio demographic, clinical, and side effect profile of patients on clozapine in Kashmir, North India

Background

Clozapine is an atypical second-generation antipsychotic belonging to the family of dibenzodiazepines. There is lack of literature on clozapine from this part of the world. So, our aim was to study the socio demographic, clinical and side effect profile of patients on clozapine in Kashmir.

Results

The mean age of the study group was 32.6 ± 8.9 years with majority being males (78.4%), unmarried (78.4%), unemployed (77.2%), and belonging to nuclear families (77.2%). Almost half of them resided in urban localities (51.1%) and studied upto middle school (55.7%). Around three- fourth (75%) of the patients had diagnosis of treatment-resistant schizophrenia. The mean dose of clozapine was 338.92 ± 158.11 mgs. Sedation (76.1%), hypersalivation (69.5%), constipation (46.6%), and weight gain (34.1%) were most common side effects noted in patients. 4.5% cases developed seizures while on clozapine. 2.3% patients developed agranulocytosis while 4.5% patients developed neutropenia on clozapine. The neutropenia was more pronounced in patients of schizophrenia with suicidal tendencies with doses of more than 400 mg.

Conclusions

We have used clozapine in a wide range of indications. Our patients seem to tolerate and respond to higher doses of clozapine and the prevalence of blood dyscrasias in our study sample was much higher than the rest of India.

Temporal trends in clozapine use at time of discharge among people with schizophrenia at two public psychiatric hospitals in Taiwan, 2006-2017

Clozapine treatment remains the gold standard for treatment-resistant schizophrenia. This study aimed to describe temporal trends in clozapine use at discharge among patients with schizophrenia at two of the largest public psychiatric hospitals in Taiwan over a twelve-year period. Patients with schizophrenia discharged from the two study hospitals between 2006 and 2017 (n = 24,101) were included in the analysis. Antipsychotic augmentation was defined as concomitant use of a second antipsychotic as augmentation to clozapine treatment. Changes in the rate of clozapine use and antipsychotic augmentation at discharge over time were analyzed using the Cochran-Armitage trend test. Patients discharged on clozapine had significantly longer hospital stays than other patients. The rate of clozapine use at discharge increased from 13.8% to 20.0% over time (Z = 6.88, p < .0001). Concomitant use of anticholinergic medication was more common in patients receiving antipsychotic augmentation than clozapine antipsychotic monotherapy. Among patients discharged on clozapine, the rate of augmentation with a second antipsychotic increased from 19.1% to 36.2% over time (Z = 6.58, p < .0001). Among patients receiving antipsychotic augmentation, use of another second-generation antipsychotic as the augmentation agent grew from 32.6% to 65.5% over time (Z = 8.90, p < .0001). The increase in clozapine use was accompanied by an increase in concomitant use of a second antipsychotic as augmentation during the study period. Further studies are warranted to clarify the risk/benefit of this augmentation strategy. Clozapine may still be underutilized, and educational programs are needed to promote clinical use of clozapine.

Prevalence and treatment of neurological and psychiatric disorders among tertiary hospitals in Pakistan; findings and implications

INTRODUCTION

Mental health and neurological disorders are prevalent in Pakistan. However, there are considerable concerns with their management due to issues of access, availability of trained personnel and stigma alongside paucity of such data. Consequently, there is a need to document current treatment approaches starting with tertiary hospitals in Pakistan where patients with more severe mental and neurological disorders are typically treated. Subsequently, use the findings to help direct future policies and initiatives.

METHODS

Multi-centered, cross-sectional, prospective study principally evaluating current medicine usage among patients attending tertiary hospitals in Pakistan with psychiatric and neurological disorders. In addition, possible factors contributing to the prevalence of these disorders in this population to help with future care. All 23 tertiary care hospitals in the ten major Districts in Pakistan were included, which cover 75% of the population.

RESULTS

57,664 patients were evaluated of which 35.3% were females. Both females and males had multiple brain disorders and multiple co-morbidities. Schizophrenia was the most prevalent disorder overall among both females (25.2%) and males (30.4%). A median of six medicines were prescribed per patient, with antipsychotics and antidepressants the most prescribed medicines. Clozapine was the most prescribed medicine in males (12.25%) and females (11.83%) including for psychiatric disorders, with sodium valproate the most prescribed medicine in epilepsy in males (42.44% of all anti-epileptic medicines) as well as females (46.38%). There was a greater prevalence of both disorders among the lower classes. A greater prevalence of schizophrenia was seen in patients abusing alcohol and smokers. The divorce rate was higher among the studied patients and the prevalence of depression was higher among the widowed population.

CONCLUSIONS

There were concerns with the quality of prescribing including the extent of polypharmacy as well as possible overuse of clozapine especially in patients with epilepsy, both of which need addressing.

Clozapine response trajectories and predictors of non-response in treatment-resistant schizophrenia: a chart review study

Although clozapine is the main antipsychotic medication for treatment-resistant schizophrenia, 40-70% of patients on clozapine have persistent psychotic symptoms (i.e. ultra-treatment-resistant schizophrenia, UTRS). We aimed to examine clozapine response/non-response patterns in patients with treatment-resistant schizophrenia, as well as determine patient clinico-demographic factors associated with long-term clozapine non-response. Clinico-demographic characteristics of 241 patients on clozapine were collected through a retrospective chart review. The median (interquartile range, IQR) follow-up from illness onset was 25.0 (IQR = 24.0) years. Clozapine response was assessed at median 10.8 (IQR = 14.0) months (Time 1, T1) and 7.2 (IQR = 13.5) years (Time 2, T2) after its initiation. It was evaluated by chart reviewers based on the information provided in clinical notes. Binomial logistic regression was used to determine clinico-demographic factors associated with clozapine non-response at both T1 and T2 (i.e. stable UTRS, S-UTRS) compared to clozapine response at both times (i.e. stable clozapine responders, S-ClozResp). Among clozapine responders (n = 122) at T1, 83.6% remained clozapine responsive and 16.4% became non-responsive at T2. In the UTRS group (n = 119) at T1, 87.4% remained clozapine non-responsive and 12.6% became responsive at T2. Duration of delay in clozapine initiation (OR = 0.94, Wald χ² = 5.33, p = 0.021) and number of pre-clozapine hospitalizations (OR = 0.95, Wald χ² = 5.20, p = 0.023) were associated with S-UTRS. Most UTRS patients were non-responsive to clozapine from the start of treatment. Preventing delay in initiating clozapine and relapses could help promote long-term clozapine response in patients with treatment-resistant schizophrenia. Future longitudinal studies are required to explore the neuropathological correlates of relapses and delay in clozapine initiation.

Clinical Course, Neurobiology and Therapeutic Approaches to Treatment Resistant Schizophrenia. Toward an Integrated View

Despite considerable psychotherapeutic advancement since the discovery of chlorpromazine, almost one third of patients with schizophrenia remain resistant to dopamine-blocking antipsychotics, and continue to be exposed to unwanted and often disabling side effects, but little if any clinical benefit. Even clozapine, the superior antipsychotic treatment, is ineffective in approximately half of these patients. Thus treatment resistant schizophrenia (TRS), continues to present a major therapeutic challenge to psychiatry. The main impediment to finding novel treatments is the lack of understanding of precise molecular mechanisms leading to TRS. Not only has the neurobiology been enigmatic for decades, but accurate and early detection of patients who are at risk of not responding to dopaminergic blockade remains elusive. Fortunately, recent work has started to unravel some of the neurobiological mechanisms underlying treatment resistance, providing long awaited answers, at least to some extent. Here we focus on the scientific advances in the field, from the clinical course of TRS to neurobiology and available treatment options. We specifically emphasize emerging evidence from TRS imaging and genetic literature that implicates dysregulation in several neurotransmitters, particularly dopamine and glutamate, and in addition genetic and neural alterations that concertedly may lead to the formation of TRS. Finally, we integrate available findings into a putative model of TRS, which may provide a platform for future studies in a bid to open the avenues for subsequent development of effective therapeutics.

Clozapine and all-cause mortality in treatment-resistant schizophrenia: a historical cohort study

OBJECTIVE

Large-scale epidemiological studies have demonstrated a protective effect of clozapine on mortality in people with schizophrenia. Clozapine is reserved for use in patients with treatment-resistant schizophrenia (TRS), but evidence of clozapine's effect on mortality exclusively within TRS samples is inconclusive. Hence, we aimed to investigate the effect of clozapine use on all-cause mortality in TRS patients.

METHODS

A historical patient cohort sample of 2837 patients, who met criteria for TRS between 1 Jan 2008 and 1 Jan 2016, were selected from the South London and Maudsley NHS Foundation Trust (SLAM) electronic health records (EHR). The national Zaponex Treatment Access System (ZTAS) mandatory monitoring system linked to the SLAM EHR was used to distinguish which patients were initiated on clozapine (n = 1025). Cox proportional hazard models were used, adjusting for sociodemographics, clinical monitoring, mental and physical illness severity and functional status.

RESULTS

After controlling for potential confounders, the protective effect of clozapine on all-cause mortality was significant (adjusted hazard ratio 0.61; 95% confidence interval 0.38-0.97; P = 0.04).

CONCLUSIONS

Clozapine reduces the risk of mortality in patients who meet criteria for TRS. We provide further evidence that improving access to clozapine in TRS is likely to reduce the mortality gap in schizophrenia.

Prescriber and institutional barriers and facilitators of clozapine use: A systematic review

BACKGROUND

As clozapine is under-prescribed in persons with treatment-resistant schizophrenia (TRS), it is necessary to better identify the determinants of health inequalities in access to clozapine use.

OBJECTIVE

To identify mental health professionals' characteristics or attitudes and institutional characteristics facilitating or limiting clozapine prescribing.

METHOD

We systematically searched multiple electronic databases for articles reporting: (i) mental health professionals' attitudes and characteristics favoring or limiting clozapine prescribing; (ii) institutional characteristics associated with variations in clozapine prescribing; (iii) interventions aimed at enhancing clozapine prescribing. Data were synthesized narratively.

RESULTS

A total of 31 articles reporting findings of 29 studies published from 1993 to 2017 in 11 countries fulfilled our inclusion criteria. The main prescriber-related barriers to clozapine prescribing are lack of personal prescribing experience and concern with pharmacological characteristics of clozapine (blood monitoring and adverse effects). Lack of knowledge about the effectiveness of clozapine does not appear as a major determinant of under-prescription. Institutional-related characteristics favoring clozapine prescribing are prescribers' adherence to evidence-based medicine principles and learning by modelling from experienced clozapine prescribers.

CONCLUSION

Effective strategies to increase access to clozapine in persons with TRS include implementation of integrated clozapine clinics, simplification of blood monitoring, education for prescribers and contact with experienced prescribers. Programs addressing barriers in clozapine prescription need to be disseminated more broadly to ensure persons with TRS have access to evidenced based treatments such as clozapine. Inequality in access to clozapine care should be more systematically handled by mental health facilities and health regulatory agencies.

The impact of delay in clozapine initiation on treatment outcomes in patients with treatment-resistant schizophrenia: A systematic review

Approximately one-third of patients with schizophrenia have treatment-resistant schizophrenia (TR-SCZ), which is a condition characterized by suboptimal response to antipsychotics other than clozapine. Importantly, treatment with clozapine-the only antipsychotic with an indication for TR-SCZ-is often delayed, which could contribute to negative outcomes. Given that the specific impact of delay in clozapine initiation is not well understood, we aimed to conduct a systematic search of the Ovid Medline^® database to identify English language publications exploring the impact of delay in clozapine initiation on treatment outcomes in patients with TR-SCZ. Additionally, clinico-demographic factors associated with clozapine delay were examined. Our search identified four retrospective studies that showed an association between longer delay in clozapine initiation and poorer treatment outcomes, even after including covariates, such as age, sex, and duration of illness. In addition, we found six studies that showed an association between age and clozapine delay, but results with regard to other clinico-demographic variables were inconsistent. Overall, the available literature reveals a possible link between delay in clozapine use and poorer treatment outcomes in patients with TR-SCZ. However, given the relatively small number of studies on this clinically important topic, future research is warranted to draw more definitive conclusions.

Clozapine Use in a Cohort of First-Episode Psychosis

PURPOSE/BACKGROUND

For approximately one third of individuals treated for psychosis or schizophrenia, antipsychotic medications will have little or no therapeutic benefit. Clozapine remains the sole medication approved for treatment-resistant schizophrenia, and studies have demonstrated its superior efficacy in reducing psychotic symptoms.

METHODS/PROCEDURES

Data were collected from the medical records of people who originally presented with a first-episode psychosis between 1995 and 1999 (N = 171). Data were obtained from first presentation up to December 31, 2013 or until the patient was discharged or transferred. Information on service use and physical health was gathered using a data collection template designed specifically for this audit.

FINDINGS/RESULTS

Twenty-eight (16.3%) of the cohort were prescribed clozapine. Data were available for 24 individuals. Of this clozapine subsample, the mean age at baseline was 23.11 (SD = 4.58); 82.14% (n = 23) were male; and 82.14% (n = 23) had a baseline diagnosis of schizophrenia. The mean time to first trial of clozapine was 6.7 years. The mean number of antipsychotics prescribed before clozapine trial was 4.85. After the initiation of clozapine, the mean number of hospital admissions reduced from 6.04 per year to 0.88 per year.

IMPLICATIONS/CONCLUSIONS

Nearly 1 in 5 of the original cohort was considered to have a suboptimal response to trials of antipsychotic medication. The use of clozapine for treatment-resistant schizophrenia is underutilized, and better understanding of the barriers to prescribing clozapine is necessary given the implications for patient's quality of life and hospital admission rates. Physical health data further emphasizes the importance of physical health monitoring in this vulnerable population.

The critical treatment window of clozapine in treatment-resistant schizophrenia: Secondary analysis of an observational study

Previous studies have suggested that a delay in initiating clozapine is one of the predictors of outcomes in treatment-resistant schizophrenia (TRS). However, whether there is a critical treatment window of clozapine in TRS and the duration of that window remain unclear. We conducted a secondary analysis of a previously published observational study using a retrospective chart review of 105 patients with TRS who were treated with clozapine. We included 90 patients who remained on clozapine for at least 3 months. The delay in initiating clozapine was an independent contributor to symptomatic improvement based on treatment with clozapine by multiple linear regression analysis. A receiver operating characteristic curve analysis (area under the curve: 0.78) confirmed 2.8 years was the best predictive cut-off value of delay in initiating clozapine for responses in patients treated with clozapine (sensitivity: 0.66, specificity: 0.84). In patients with a delay in initiating clozapine of ≤2.8 years and a delay in initiating clozapine of >2.8 years, the response rates were 81.6% and 30.8% (risk ratio=2.65; 95% confidence interval, 1.80, 3.63), respectively. Clinicians should reduce the delay in initiating clozapine to less than 3 years to improve symptomatic outcomes in TRS and to prevent clozapine-resistant schizophrenia.

Correlates of Clozapine Use after a First Episode of Schizophrenia: Results From a Long-term Prospective Study

BACKGROUND

Earlier commencement of clozapine has been related to a better response in treatment-resistant schizophrenia.

OBJECTIVES

To identify variables that predict clozapine use after a first episode of schizophrenia (FES).

METHODS

Patients with FES and ≤15 days of lifetime antipsychotic treatment were followed up during naturalistic treatment, and the patients who were initiated on clozapine were compared with those receiving non-clozapine antipsychotics for ≥24 months regarding demographic and clinical baseline characteristics, adherence, and relapse patterns during follow-up. Treatment-resistant schizophrenia was defined as two or more antipsychotic trials of adequate dose for ≥6 weeks.

RESULTS

Twenty-eight patients who used clozapine and 77 non-clozapine antipsychotic users were included. Clozapine was initiated after a mean of 2.5 ± 1.1 adequate antipsychotic trials. Eight of the 28 clozapine-treated patients (28.6 %) began their clozapine treatment during the first 12 months of follow-up (mean 7.1 ± 3.3 months) and their premorbid childhood adjustment was significantly worse than those who started clozapine later (mean 78.5 ± 43.0 months). Compared with non-clozapine users, patients who started clozapine had significantly more relapses in the first 6 months of follow-up prior to clozapine use (35.7 vs. 11.7 %, p = 0.005), and were significantly more likely to have a first relapse despite treatment adherence (38.1 vs. 73.3 %, p = 0.01). In the multivariate analyses, antipsychotic polypharmacy and first relapse despite adherence to antipsychotic treatment independently predicted subsequent clozapine use.

CONCLUSIONS

Clozapine use after a FES was predicted by a first relapse while being adherent to non-clozapine antipsychotics, especially if the first relapse occurred within the first 6 months. Developmental childhood difficulties predicted significantly earlier clozapine use.

Factors associated with changes in hospitalisation in patients prescribed clozapine

OBJECTIVE

The objective of this study was to examine whether delays in clozapine treatment affect outcomes once clozapine is started and identify factors that affect these outcomes.

METHOD

Patients starting clozapine in a four year period at South London and the Maudsley NHS Foundation Trust were included. Clinical details were gathered from clinical notes. Primary outcome was net change in inpatient admissions comparing the periods before and after clozapine was started.

RESULTS

There was no significant association between the length of clozapine delay (mean clozapine delay = 3.93 years) and number or length of inpatient admissions once clozapine had been started (mean net change in days of admission = 16.74 days), F value = 0.901, p = 0.345. Clozapine reduced the total number of bed days per year, but only if treatment was continued - stopping resulted in inpatient admissions returning to pre-clozapine levels. Younger patients had a greater reduction in bed days when taking clozapine (p = 0.027).

CONCLUSION

Clozapine reduces the number of inpatient days, regardless of the chronicity of the illness at the time clozapine was started. Continued compliance with clozapine is necessary to maintain this benefit. Reduction in bed days is greater in younger patients, suggesting early initiation of clozapine may be beneficial.

Treatment-Resistant Schizophrenia Patients Show Elevated Anterior Cingulate Cortex Glutamate Compared to Treatment-Responsive

INTRODUCTION

Resistance to antipsychotic treatment is a significant clinical problem in patients with schizophrenia with approximately 1 in 3 showing limited or no response to repeated treatments with antipsychotic medication. The neurobiological basis for treatment resistance is unknown but recent evidence implicates glutamatergic function in the anterior cingulate cortex. We examined glutamate levels of chronically ill treatment-resistant patients directly compared to treatment-responsive patients.

METHODS

We acquired proton magnetic resonance spectroscopy (1H-MRS) at 3 Tesla from 21 treatment-resistant and 20 treatment-responsive patients. All participants had a DSM-IV diagnosis of schizophrenia. Treatment-resistant patients were classified using the modified Kane criteria. The groups were matched for age, sex, smoking status, and illness duration.

RESULTS

Glutamate to creatine ratio levels were higher in treatment-resistant patients (Mean [SD] = 1.57 [0.24]) than in treatment-responsive patients (Mean[SD] = 1.38 [0.23]), (T[35] = 2.34, P = .025, 2-tailed), with a large effect size of d = 0.76. A model assuming 2 populations showed a 25% improvement in the fit of the Akaike weights (0.55) over a model assuming 1 population (0.44), producing group values almost identical to actual group means.

DISCUSSION

Increased anterior cingulate glutamate level is associated with treatment-resistant schizophrenia. This appears to be a stable neurobiological trait of treatment-resistant patients. We discuss possible explanations for glutamatergic dysfunction playing a significant role in resistance to conventional antipsychotic treatments, which are all dopamine-2 receptor blockers. Our findings suggest that glutamatergic treatments may be particularly effective in resistant patients and that 1H-MRS glutamate indices can potentially have clinical use.

Delayed initiation of clozapine may be related to poor response in treatment-resistant schizophrenia

The aim of this retrospective chart-review study was to investigate the relationship between delayed commencement of clozapine and the level of response in treatment-resistant schizophrenia (TRS). We included 162 patients with schizophrenia who used clozapine. The mean delay until starting clozapine after fulfillment of the TRS criteria was 29 months. The delay was shorter in those who gained benefit from clozapine (P=0.04), those who were treated in a specialized psychosis outpatient unit (P=0.01), and in men (P=0.009), and it correlated with age (P<0.001). The delay in starting clozapine and the maximum clozapine dose were independent contributors toward the response to clozapine in the logistic regression analysis. Moreover, of those who gained considerable benefit from clozapine, the patients were younger (P=0.01), the duration of illness before clozapine treatment was shorter (P=0.001), and the numbers of adequate antipsychotic trials before the use of clozapine were fewer (P=0.05). Our findings suggest that efforts aimed at reducing the delay for starting clozapine may increase the effectiveness of clozapine in TRS.

Clozapine use in childhood and adolescent schizophrenia: A nationwide population-based study

Early onset schizophrenia (EOS) begins in childhood or adolescence. EOS is associated with poor treatment response and may benefit from timely use of clozapine. This study aimed to identify the predictors of clozapine use in EOS and characterize the clinical profile and outcome of clozapine-treated youths with schizophrenia. We conducted a nationwide population-based study using linked data from Danish medical registries. We examined all incident cases of EOS (i.e., cases diagnosed prior to their 18th birthday) between December 31st 1994 and December 31st 2006 and characterized their demographic, clinical and treatment profiles. We then used multivariable cox proportional hazard models to identify predictors of clozapine treatment in this patient population. We identified 662 EOS cases (1.9% of all schizophrenia cases), of whom 108 (17.6%) had commenced clozapine by December 31st 2008. Patients had on average 3 antipsychotic trials prior to clozapine initiation. The mean interval between first antipsychotic treatment and clozapine initiation was 3.2 (2.9) years. Older age at diagnosis of schizophrenia [HR=1.2, 95% CI (1.05-1.4), p=0.01], family history of schizophrenia [HR=2.1, 95% CI (1.1-3.04), p=0.02] and attempted suicide [HR=1.8, 95% CI (1.1-3.04), p=0.02] emerged as significant predictors of clozapine use. The majority of patients (n=96, 88.8%) prescribed clozapine appeared to have a favorable clinical response as indicated by continued prescription redemption and improved occupational outcomes. Our findings support current recommendations for the timely use of clozapine in EOS.

Delay in initiation of clozapine: a retrospective study from a tertiary care hospital in North India

This study aimed to assess the delay in initiation of clozapine, number of adequate antipsychotic trials prior to starting clozapine and practice of polypharmacy prior to starting clozapine. A retrospective study design was followed. Treatment records of 200 patients started on clozapine during the period of January 2006-June 2014 were reviewed. The mean delay in clozapine initiation was 1.93 (S.D. 1.82) years and median was 1.5 years. Mean of 3 (S.D. 1.18) adequate antipsychotic trials was given prior to considering clozapine and 27.5% patients had received polypharmacy prior to clozapine. Factors related to delay in starting of clozapine included higher age, longer duration of illness, age more than 20 years of age, polypharmacy, use of an adequate trial of typical antipsychotic medication, patients from urban locality and those with onset of illness prior to introduction of clozapine into Indian market. Findings of the present study suggest that there is a delay of 1.5-2 years in starting of clozapine and about one-fourth of patients receive polypharmacy prior to receiving clozapine. These finding suggests that there is a need to change the prescribing habits to reduce the delay in starting of clozapine.

Pathway to clozapine use: a comparison between a patient cohort from New Zealand and a cohort from the United Kingdom

BACKGROUND AND OBJECTIVE

Clozapine has been available since the early 1990s. Studies continue to demonstrate its superior efficacy in treatment-resistant schizophrenia. Despite this, numerous studies show under-utilisation, delayed access and reluctance by psychiatrists to prescribe clozapine. This retrospective cross-sectional study compared the prescribing of clozapine in two adult cohorts under the care of large public mental health services in Auckland (New Zealand) and Birmingham (United Kingdom) on 31 March 2007.

METHOD

Time from first presentation to clozapine initiation, prior antipsychotics trialled and antipsychotic co-prescribing were compared. Data included demographics, psychiatric diagnosis, co-morbid conditions, year of first presentation, admissions and pharmacological treatment (clozapine dose, start date, prior antipsychotics, co-prescribed antipsychotic).

RESULTS

Overall, 664 people were prescribed clozapine (402 Auckland; 262 Birmingham); mean daily dose of 384 mg (Auckland) and 429 mg (Birmingham). 53 % presented after 1990 and the average duration of time before starting clozapine was significantly longer in the Birmingham cohort (6.5 vs. 5.3 years) but this reduced in both cohorts to a 1-year mean in those presenting within the last 3 years. The average number of antipsychotics trialled pre-clozapine for those presenting since 1990 was significantly higher in the Birmingham cohort (4.3 vs. 3.1) but in both cohorts this similarly reduced in those presenting within the last 3 years. Antipsychotic co-prescribing was significantly higher in the Birmingham cohort (22.9 vs. 10.7 %).

CONCLUSIONS

There is evidence that access to clozapine has improved over time in both cohorts, with a reduction in the duration between presentation and initiation of clozapine and number of different antipsychotics trialled pre-clozapine. These are very positive findings in terms of optimising outcomes with clozapine and are possibly due to the impact of guideline recommendations, increasing clinician, consumer and carer knowledge, and experience with clozapine and funding changes.

Clozapine and visuospatial processing in treatment-resistant schizophrenia

INTRODUCTION

Clozapine, the most widely used option in treatment-resistant schizophrenia, has been shown to be superior to other antipsychotic medications in improving cognitive function in patients. However, the results have not been consistent and the mechanisms underlying this effect have not been elucidated. Thus, the purpose of the present study was to evaluate verbal and nonverbal cognition (using visuospatial processing tests) in patients treated with clozapine (initially treatment resistant) and those treated with other second-generation antipsychotics, relative healthy control subjects. Furthermore, we examined neural correlates of visuospatial processing in the three groups.

METHODS

Twenty schizophrenia patients treated with clozapine (TR-C group), 23 patients stabilised with atypical antipsychotics other than clozapine (NTR group), and 21 healthy control participants completed a battery of verbal and visuospatial cognitive tests. In addition, participants underwent functional magnetic resonance imaging (fMRI) while performing one of the visuospatial tests (the mental rotation task). The fMRI data were analysed separately in each group using Statistical Parametric Mapping software (SPM5).

RESULTS

Overall, schizophrenia patients exhibited deficit on verbal and nonverbal processing relative to the healthy controls, but we observed some interesting differences between the two groups of patients. Specifically, the NTR group performed better than the TR-C group on the Block Design and the Raven's Progressive Matrices. With respect to brain function during mental rotation, the NTR group showed significant activations in regions of the temporal and occipital cortex, whereas the TR-C patients did not. The relative deactivations associated with the task were also more robust in NTR compared to the other group of patients, despite a similar performance.

CONCLUSION

Present results suggest better visuospatial processing in the NTR relative to the TR-C group. This difference could be attributed to the treatment resistance itself or a lack of beneficial effect of clozapine relative to other atypical antipsychotics in ameliorating nonverbal abilities. Future studies of the relationship between clozapine and cognition, as well as between treatment resistance and cognition, are warranted.

Clozapine and therapeutic drug monitoring: is there sufficient evidence for an upper threshold?

RATIONALE

Clozapine levels are advocated in the monitoring of patients on this drug and have now been used for a number of years. A safety-related threshold has also been proposed, as well as therapeutic lower and upper thresholds. While there has been reasonable consensus regarding a lower therapeutic threshold, this is not the case for the upper thresholds.

OBJECTIVES

Our aim was to review available evidence related to upper thresholds.

METHODS

We carried out an electronic search of different databases and a manual search of articles between 1960 and 2011, cross-referencing the following terms with clozapine-interactions, monitoring, pharmacokinetics, plasma levels, serum levels, and toxicity.

RESULTS

Sixty-nine articles met our search criteria and these could be divided into reviews (11), studies (24), and case reports (35). Study quality was evaluated, and none met criteria for a prospective, randomized controlled trial specifically addressing higher plasma levels, e.g., >500 ng/ml. Case reports emphasize in particular the impact of interactions, e.g., antidepressants and smoking. There is clear evidence indicating a dose-related increased risk of seizures, at least to 500-600 mg/day, but a lack of data to suggest such a relationship between plasma levels, dose, and side effects linked to safety, e.g., seizures, myocarditis, and agranulocytosis. The very limited evidence addressing an upper threshold related to clinical response suggests a "ceiling effect" in the range of 600-838 ng/ml.

CONCLUSIONS

It appears that the current safety-related threshold is not supported by evidence. There may be an upper threshold for clinical response, beyond which chance of response falls off, although further studies are warranted.

Adherence to treatment guidelines in clinical practice: study of antipsychotic treatment prior to clozapine initiation

BACKGROUND

Clozapine is the only antipsychotic drug licensed for treatment-resistant schizophrenia but its use is often delayed. Since previous studies, national guidelines on the use of clozapine and other antipsychotics have been disseminated to clinicians.

AIMS

To determine the theoretical delay to clozapine initiation and to quantify the prior use of antipsychotic polypharmacy and high-dose antipsychotic treatment.

METHOD

Clinico-demographic data were extracted from the treatment records of all patients commencing clozapine in our centre between 2006 and 2010.

RESULTS

Complete records were available for 149 patients. The mean theoretical delay in initiating clozapine was 47.7 months (s.d. = 49.7). Before commencing clozapine, antipsychotic polypharmacy and high-dose treatment was evident in 36.2 and 34.2% of patients respectively. Theoretical delay was related to illness duration (β = 0.7, P<0.001) but did not differ by gender or ethnicity.

CONCLUSIONS

Substantial delays to clozapine initiation remain and antipsychotic polypharmacy and high doses are commonly used prior to clozapine, despite treatment guidelines.

Use of clozapine for the treatment of schizophrenia: findings of the 2006 research on the china psychotropic prescription studies

OBJECTIVE

Clozapine is one of the most commonly used antipsychotic drugs in China. To date, few studies have investigated the patterns the prescription of clozapine nationwide. The present study examined these patterns in China in 2006 and identified the demographic and clinical characteristics associated with the use of clozapine.

METHODS

Using a standardized protocol and data collection procedure, we surveyed 5,898 patients with schizophrenia in 10 provinces with differing levels of economic development.

RESULTS

Overall, clozapine had been prescribed for 31.9% (n=1,883) of the patients; however we found considerable variation among the 10 provinces. The frequency of clozapine use was highest in Sichuan (39.3%) and lowest in Beijing (17.3%). The mean daily dose of clozapine was 210.36±128.72 mg/day, and 25.1% of the patients were treated with clozapine in combination with other antipsychotics. Compared with the group not receiving clozapine, clozapine-user had been treated for longer durations and had experienced a greater number of relapses and hospitalizations. Furthermore, those in the clozapine-user had lower family incomes, were less able to seek psychiatric services, and more likely to be male and have a positive family history of schizophrenia. A multiple logistic regression analysis revealed that age, sex, professional help-seeking behaviors, duration of illness, economic status, educational level, and clinical manifestations were associated with the use of clozapine.

CONCLUSION

Clozapine use is common in China. However, use of the antipsychotic varies among provinces, and demographic and clinical factors play important roles in the prescription of clozapine.