Reasons for clozapine discontinuation in patients with treatment-resistant schizophrenia

Therapeutic Reference Range for Clozapine Plasma Levels in Parkinson's Disease or Dementia: A Systematic Review and Individual Participant Data Meta-analysis

Clozapine is a recommended treatment for psychotic symptoms in patients with Parkinson's disease (PD) and/or dementia. However, the therapeutic reference range for clozapine in these patients has not been established hitherto.The study was performed in three university hospitals in Germany and Switzerland, including clozapine-treated patients with PD and/or dementia. The primary outcome was tolerability based on reports of adverse drug reactions and/or changes in laboratory tests or electrocardiogram and/or clozapine discontinuation. We meta-analyzed demographic and pharmacokinetic parameters in patients tolerating clozapine well versus not. A meta-analytic summary receiver operating characteristic (SROC) to establish the clozapine upper level associated with poor tolerability was estimated.We analyzed a total of 99 patients suffering from PD (56.6%) and/or dementia (49.5%) with a mean age of 70.3±9.5 years and 41.4% females; poor tolerability was reported in 26 of 99 patients (26.3%). When comparing patients with and without poor tolerability, there were no differences in age, body mass index, sex, smoking, or clozapine dose, nor did we find statistically significant differences in clozapine levels (standardized mean difference 0.46, 95% confidence interval - 0.04 to 0.96, p=0.07), and heterogeneity was low (I2=0.0%). Clozapine blood levels above 193 ng/mL were associated with poor tolerability (SROC area-under-curve 0.6, sensitivity 39.7%, specificity 79.9%).One of four patients with PD and/or dementia treated with clozapine did not tolerate clozapine well, which was associated with a trend toward elevated clozapine concentrations. Monitoring drug levels may help to improve tolerability in these patients.

Exploring the factors and outcomes of clozapine discontinuation in India: A retrospective analysis

BACKGROUND

Clozapine is used in the management of treatment-resistant schizophrenia. Although the reported adverse effects with clozapine are more, and the risk of clozapine discontinuation is present, few Indian studies have examined the correlates of clozapine discontinuation. Furthermore, there is a lack of consensus on alternative treatment after clozapine discontinuation. This study aimed to explore these factors among patients treated in a tertiary psychiatric centre in India.

METHODS

We performed a retrospective chart review of the clozapine database from tertiary care schizophrenia clinic services (2015-2023) and identified 30 eligible case records of clozapine discontinuation. We examined the correlates of clozapine discontinuation.

RESULTS

Among patients who discontinued clozapine, 66.7 % were male, with an average age of 32.30 ± 9.78 years. The most common causes for discontinuation were adverse effects(56.67 %), inadequate therapeutic response(23.34 %), and non-adherence(13.33 %). Down-titration was used for 58.82 % (10/17 in whom discontinuation method details were available) of patients, with no withdrawal adverse effects noted. Clozapine retrial was considered among nine patients. Following clozapine discontinuation, among the interventions tried, ECT showed a significant response, followed by haloperidol and risperidone. Amisulpride, olanzapine, and flupentixol depot showed a moderate response.

CONCLUSIONS

These results align with previous studies, showing that adverse effects and inadequate response are prominent reasons for clozapine discontinuation and demonstrate the possibility of clozapine retrial in selected patients. Managing adverse effects might result in improvement, at least to a mild degree. Clozapine discontinuation can be avoided in a cohort with non-serious adverse effects, given the superiority of clozapine in resistant schizophrenia.

Clinical and Demographic Predictors of Early Clozapine Discontinuation Across Mood and Psychotic Disorders

BACKGROUND

Clozapine is effective for treatment-resistant schizophrenia and bipolar disorder but is often discontinued due to adverse effects. This study compared early clozapine discontinuation rates and reasons in patients with mood and psychotic disorders.

METHODS

Data from all individuals with mood or psychotic disorders who initiated clozapine for the first time at the inpatient psychiatric unit of Mayo Clinic, Rochester, Minnesota, between 2014 and 2022 were retrospectively analyzed. Early clozapine discontinuation, defined as discontinuation within 90 days of initiation, was the primary outcome. Cox proportional hazards regression was used to assess factors associated with discontinuation.

RESULTS

Of 83 patients (mood group n = 37, psychosis group n = 46), those in the mood group were older ( P = 0.022) and more likely to be nonsmokers ( P = 0.034). The overall 90-day clozapine discontinuation rate was 45.7%. Early discontinuation was significantly higher in the mood group than in the psychosis group (hazard ratio = 2.41, 95% confidence interval = 1.26-4.64, P = 0.008). Other factors associated with early discontinuation were female sex ( P = 0.033), older age ( P = 0.026), and nonsmoking ( P = 0.001). In multivariable analysis, smoking status was the only factor significantly inversely associated with early clozapine discontinuation (hazard ratio = 0.47, 95% confidence interval = 0.22-0.99, P = 0.048), while diagnostic group, sex, and age did not show significant associations (all P > 0.05). Discontinuations were primarily due to adverse drug reactions in both groups.

CONCLUSIONS

Nearly half of the patients discontinued clozapine early, with higher rates in the mood group. Studies should further explore potential pharmacodynamic and pharmacokinetic factors associated with discontinuation, including the influence of smoking. Careful monitoring and personalized management of side effects are crucial for optimizing clozapine therapy and improving treatment outcomes.

What is the current scope of research assessing patients' and clinicians' perspectives on clozapine treatment? A comprehensive scoping review

OBJECTIVES

Clozapine is continuously underused. The existing systematic reviews addressing barriers to clozapine prescribing primarily focus on clinical staff's attitudes and perceived barriers to prescribing. However, a preliminary literature search revealed additional literature on the subject not previously included in systematic reviews, including literature on patient perspectives. A scoping review is warranted to map the scope of primary studies on patients' and/or clinicians' perspectives on clozapine treatment and to identify gaps in research.

DESIGN

A scoping review was designed and reported in accordance with established guidelines for scoping reviews.

DATA SOURCES

The electronic databases Cochrane Library, CINAHL, Web of Science, PsycINFO, MEDLINE, EMBASE, Google Scholar and two grey literature databases were searched. Furthermore, citation tracking of selected studies was undertaken.

ELIGIBILITY CRITERIA

We included primary, empirical studies reporting clinicians' and/or patients' perspectives on clozapine treatment. No limitation was set for the year of publication or type of primary study.

DATA EXTRACTION AND SYNTHESIS

Two researchers independently screened for studies, extracted the data and coded the content. Findings were summarised visually and narratively.

RESULTS

146 studies were included. Most studies reported on patients' or clinicians' perspectives on active clozapine treatment or on clinicians' perspectives on barriers to clozapine initiation in general. Three gaps in research were identified: (1) clozapine-eligible, yet clozapine-naïve, patients' attitudes towards clozapine commencement, (2) clinicians' reasons for clozapine withholding and perceived facilitators of clozapine treatment in specific patient-cases and (3) patient and clinician perspectives on clozapine discontinuation, continuation and rechallenge in specific patient cases.

CONCLUSIONS

Research on clozapine perspectives tends to repeat itself. Future studies addressing the identified gaps in evidence could provide the insights needed to optimise clozapine utilisation.

Association between initial pattern of clozapine titration, concentration-to-dose ratio, and incidence of fever in patients with schizophrenia spectrum disorders in a Korean tertiary hospital

Safe and effective administration of clozapine requires careful monitoring for inflammatory reactions during the initial titration. The concentration-to-dose (C/D) ratio must be taken into account, which may vary among ethnicities. In this retrospective study, 1408 Korean schizophrenia inpatients were examined for during the first 8 weeks of clozapine titration. The average doses of clozapine administered during weeks 1, 2, 4, and 8 were 77.37, 137.73, 193.20, and 212.83 mg/day, with significantly lower doses for females than males. The average C/D ratio was significantly higher in females (1.75 ± 1.04 and 1.11 ± 0.67 ng/mL per mg/day). Patients with higher C/D ratios were more likely to experience fever and were prescribed lower doses of clozapine starting from week 4. In total, 22.1 % of patients developed a fever at an average of 15.74 days after initiating clozapine. Patients who developed a fever were younger, used more antipsychotics at baseline, had a higher C/D ratio, and had a higher incidence of an elevated C-reactive protein level. A higher C/D ratio, use of a greater number of antipsychotics at baseline, and concomitant olanzapine use were risk factors for the development of inflammatory reactions. The incidence of pneumonia, agranulocytosis, and myocarditis within 8 weeks were 3.7 %, 0.3 %, and 0.1 %. In summary, the target dose of clozapine titration is lower for Korean schizophrenia patients, with a higher C/D ratio and more frequent fever compared to Western patients; however, myocarditis occurs rarely. Our findings may contribute to the titration methods for clozapine for the East Asian population.

Clinician Reasons for Stopping Clozapine: A Retrospective Cohort Study

BACKGROUND

Little information is available on clozapine discontinuation rates in developing country settings.

AIM

The present study aimed to evaluate the incidence and reasons clinicians stopped clozapinine in patients after initiating treatment with the same. In addition, the study also aimed to assess the rechallenge rate, that is, restarting clozapine after a decision to discontinue the same by the clinicians.

METHODOLOGY

The treatment records of 859 patients started on clozapine were reviewed to identify the patients for whom the clinician stopped clozapine at least once because of any reason. The reasons for stopping clozapine were reviewed. In addition, the treatment records were also examined for rechallenge with clozapine at a later date.

RESULTS

Clozapine was stopped by the clinicians in 44 of the 859 patients (5.12%). The most common reason for stopping clozapine was blood dyscrasias (n = 12), followed by poor adherence making the hematological monitoring difficult (n = 9), and intolerable sedation (n = 7). In half of the patients (n = 22), clozapine was restarted by the clinicians for further management of schizophrenia. Successful rechallenge was done in 58.33% of patients with blood dyscrasias, 44.44% with poor adherence, and 71.4% with intolerable sedation.

CONCLUSIONS

The present study suggests clinicians stop clozapine in only 5.14% of cases. The most common reasons for clozapine discontinuation by clinicians include blood dyscrasias, poor medication adherence making it challenging to monitor the hemogram, and sedation. However, in half of the patient's clozapine was rechallenged, and all the attempts of rechallenging were successful.

Dropout rates and reasons for dropout among patients receiving clozapine

BACKGROUND AND AIM

The present study aimed to assess the treatment dropout rates, reasons for treatment dropout, and clozapine discontinuation rate among patients attending a tertiary care center in North India.

MATERIALS AND METHODS

Clozapine data bank was used to identify patients on clozapine, and their treatment records were reviewed for the period Jan 2020-March 2020. Patients who did not follow-up at least once in the last 6 months were considered to have dropped out and were contacted telephonically to understand the reasons for dropout. Treatment records of those following up regularly were reviewed to check if clozapine was discontinued and if so, the reason for the same was evaluated.

RESULTS

Out of 671 patients on clozapine, 495 (73.8%) were still on regular follow-up and the remaining 176 (26.2%) had dropped out of treatment. Out of the 176 patients who had dropped out of treatment, 84 could be contacted. Common reasons for dropout were long distance from the hospital (n = 27), long waiting time for consultation (n = 8), no benefit with treatment (n = 17), side effects with medication (n = 10), moving away to another place (n = 6), refusal by the patient to follow-up (n = 7), patient improved and so did not feel the need to continue treatment (n = 7), and other reasons (n = 37).

CONCLUSION

About one-fourth of patients who had started treatment with clozapine dropped out from the treatment. The most common reasons for dropout from treatment included long distance from the hospital and no benefit from treatment.

What are patients' experiences of discontinuing clozapine and how does this impact their views on subsequent treatment?

BACKGROUND

Discontinuing what is considered the most effective treatment for treatment-resistant schizophrenia may precipitate feelings of failure or a relapse of illness. Clozapine treatment is discontinued for a variety of reasons, including non-adherence, intolerance, or lack of efficacy. Patients' experiences of discontinuing the "best" treatment and the impact on perceptions of subsequent antipsychotic treatment are important in developing an understanding of the factors affecting people's treatment choices. This study is the first of its type, seeking to explore people's perspectives on clozapine discontinuation.

METHOD

Semi-structured interviews with sixteen patients who had received clozapine and discontinued treatment-thirteen males and three females, age range: thirty-two to seventy-eight years old-were audio-recorded and transcribed. A modified inductive approach to analysis, based on grounded theory, was taken to identify commonalities and differences in patients' perceptions.

RESULTS

The three main themes identified from participants' experiences were: (1) positive and negative effects of treatment; (2) feelings of agency, being the capacity to make decisions about treatment and act independently; (3) choice of treatment in the future. Participants exhibited agency in making choices about medication, including risking relapse, while attempting self-management of medication effects. Different participants perceived the same side effect as beneficial or intolerable. Variation in subsequent treatment choices was reported, with some participants favouring depot (long-acting) injections. A participant was frightened when not told about clozapine's side effects, which led to the participant not being engaged in future treatment decisions. Others, despite suffering serious adverse effects, retained positive perceptions of clozapine; they experienced despair at finding an effective alternative.

CONCLUSIONS

Experiences with clozapine discontinuation evoked powerful emotions and resulted in clozapine being the benchmark for other treatments. Knowledge, agency, and being in control were important to participants in relation to treatment. Personal perceptions of treatments or beliefs about illness could lead to non-adherence. People value the clinician listening to their experiences to better understand their perspective, enabling concerns about medication to be addressed through true shared decision making.

TRIAL REGISTRATION

NHS Health Research Authority and Health and Care Research Wales, IRAS Project ID 225753, Research Ethics Committee (REC) reference: 18/NW/0413, 25/06/2018.

Rates and Reasons for Clozapine Treatment Interruptions: Impact of the Frequency of Hematologic Monitoring and Cardiac Adverse Events

BACKGROUND

Differing rates and reasons for interruptions of clozapine treatment have been reported globally. This article evaluated the rates and reasons for clozapine therapy interruptions in Australia and explored the impact of the frequency of hematological monitoring on these parameters.

METHODS

Data of the patients who were newly commenced on clozapine at three metropolitan public mental health services in Western Australia over 11 years were retrospectively collated. The rate and reasons for clozapine therapy interruptions and their association with the frequency of hematological monitoring, age, sex, and treatment site were analyzed using parametric, nonparametric, and correlational analyses.

RESULTS

Of the 457 patients whose data were collected, 69.6% had an interruption of treatment with 41.2% of those occurring during the period of mandatory weekly hematological monitoring in the first 18 weeks. Nonadherence (57.4%) and adverse effects (28.8%) were the 2 main reasons for the treatment interruptions. Cardiac issues accounted for the majority of the interruptions (61.8%) due to specified adverse effects, and these occurred significantly more commonly within the first 18 weeks. Location, age, and sex did not predict the possibility of treatment interruptions.

CONCLUSIONS

The high rates of clozapine treatment interruption observed during the period of weekly monitoring point toward the need to address the burden of frequent hematological monitoring for patients. Disproportionately higher rates of interruption due to cardiac adverse effects observed in this study compared with research from non-Australian settings raise the possibility of geographical differences in the adverse effects leading to treatment discontinuation.

Cariprazine - an Alternative Treatment for Clozapine-resistant Schizophrenia?

Treatment-resistant schizophrenia (TRS) poses a significant therapeutic challenge in psychiatric practice. Clozapine is recognized as a treatment of choice in TRS but is not always effective in alleviating patients' symptoms. Additionally, clozapine therapy is associated with multiple side effects and monitoring requirements that often limit its use and negatively affect patients' compliance with the treatment. Although clozapine augmentation options are available, there is currently no alternative monotherapy proven to be effective in TRS. We present a case of a young man with TRS who failed to respond to appropriate trials of risperidone, aripiprazole and also clozapine, and who experienced impairing adverse effects of clozapine that made further clozapine treatment not only futile but also detrimental to his health. He was successfully treated with cariprazine monotherapy, which culminated in the remission of his both positive and negative symptoms of psychosis as well as in the marked improvement in social functioning. Cariprazine, a newer atypical antipsychotic endowed with a D3-preferring mode of action, may offer a better tolerated and more acceptable treatment option for patients with difficult-to-treat psychotic symptoms.

Antipsychotic Drug Development: From Historical Evidence to Fresh Perspectives

Schizophrenia is a complex disorder of varied etiology, manifesting symptoms that can differ between patients and change throughout an individual's lifespan. Antipsychotic drugs have evolved through first (e.g., haloperidol), second (olanzapine and clozapine) and a possible third (aripiprazole) generation of drugs in an attempt to improve efficacy and tolerability, with minimal side-effects. Despite robust scientific efforts over the past 70 years, there remains a need to develop drugs with greater efficacy, particularly in relation to the negative and cognitive symptoms of schizophrenia, addressing treatment resistance, with a lower side-effects profile compared to existing antipsychotic drugs. Identifying and investigating novel therapeutic targets remains an important component of future antipsychotic drug discovery; however, mounting evidence demonstrates neurobiological, neuroanatomical and functional heterogeneity in cohorts of individuals with schizophrenia. This presents an opportunity to refresh the approach to drug trials to a more targeted strategy. By increasing understanding of the basic science and pharmacological mechanisms underlying the potential antipsychotic efficacy of novel therapeutics prior to clinical trials, new drugs may be appropriately directed to a target population of schizophrenia subjects based on the drug mechanisms and correlating biological sub-groupings of patient characteristics. Improving the lives of sub-populations of people with schizophrenia that share common biological characteristics and are likely to be responsive to a particular compound may be more achievable than aiming to treat the complexities of schizophrenia as a homogenous disorder. This approach to clinical trials in antipsychotic research is discussed in the present review.

Combination With Long-Acting Injectable Antipsychotics and Utilization of Nonstandard Formulations as Compliance Enhancing Methods for Clozapine Users: A Systematic Review and A Case Series

BACKGROUND

Combining clozapine with a long-acting injectable antipsychotic (LAI) or using different, nonstandard formulations of the compound may improve treatment outcomes. We aimed to investigate the utility of the clozapine-LAI combination and different formulations of clozapine for compliance problems of clozapine treatment, and to describe a case series on the combined treatment.

PROCEDURES

We conducted a PubMed search with no date restriction. The number and length of hospitalizations, the results of clinical scales, and adverse events were recorded. We also present a case series of 18 patients using the clozapine-LAI combination. Data were collected from the medical charts and electronic records.

RESULTS

We extracted 9 records describing the use of the clozapine-LAI combination. The case reports and mirror-image studies showed a significant reduction in the number of hospitalizations, length of hospital stays, and number of visits to the emergency department on the combined treatment with no serious adverse events. We included 11 articles for clozapine formulations. The case reports and retrospective data suggested that short-acting intramuscular clozapine was often well tolerated and resulted in an increased acceptance of oral clozapine in the acute phase of illness. In our case series, illness severity and the number of hospitalization per year significantly decreased after the combined treatment, besides a significant improvement in the functioning scores. Hyperprolactinemia and extrapyramidal side effects were reported due to concomitant LAIs.

CONCLUSIONS

Despite the encouraging evidence, the present data are preliminary and mostly based on retrospective studies, and oral-dissolving tablets or oral liquid formulations of clozapine have insufficient evidence for clinical practice. Well-designed, controlled, follow-up studies are needed for both clozapine-LAI combination and different formulations of clozapine.

Demographic and clinical characteristics of patients who recommence clozapine following therapy interruptions

OBJECTIVE

The proportion of patients who recommence clozapine after cessation, the time taken to resume clozapine post-cessation, and distinguishing demographic and clinical characteristics of this group have been poorly researched. We evaluated these in the current study.

METHOD

We retrospectively extracted selected demographic and clinical variables and clozapine treatment interruption and recommencement data up to December 2018 of a cohort of 458 patients who first commenced clozapine between 2006 and 2016. The study was conducted at three Australian health services.

RESULTS

Of the 310 (69%) patients who had at least one interruption of clozapine treatment, 170 (54.8%) did not resume clozapine, and 140 (45.2%) recommenced it after the first interruption. More than half of those who recommenced did so within a month and 80% by 12 months. Cox regression analysis revealed that age was significantly associated with recommencement, with a 2% decrease in the likelihood of restarting after an interruption for each year later that clozapine was initially commenced (HR = 0.98 95%CI: 0.97, 0.997, p = 0.02). Those who ceased clozapine due to adverse effects were less likely to restart than those who ceased due to noncompliance (HR = 0.63 95%CI: 0.41, 0.97, p = 0.03). More time on clozapine prior to interruption increased the likelihood of restarting it, with each additional month on clozapine increasing this likelihood by 1% (HR = 1.01 95%CI: 1.01, 1.02, p < 0.001).

CONCLUSION

If the distinguishing demographic and clinical characteristics of the group identified in this study are corroborated through further research, this could further validate the need to identify treatment resistance and commence clozapine early in people with schizophrenia and provide appropriate interventions to those more at risk of permanent discontinuation of clozapine.

Metabolite Profiling of Clozapine in Patients Switching Versus Maintaining Treatment: A Retrospective Pilot Study

PURPOSE/BACKGROUND

Pharmacokinetics may be of relevance for the risk of clozapine discontinuation. We compared metabolite profiles, accounting for smoking habits, in patients switching versus maintaining clozapine treatment at therapeutic concentrations.

METHODS/PROCEDURES

Adult patients with clozapine serum levels above 1070 nmol/L (350 ng/mL) were retrospectively included from a Norwegian therapeutic drug monitoring service during 2018-2020. Inclusion criteria were (1) known smoking habits, (2) blood sample drawn within 10 to 30 hours after last clozapine intake, and (3) detectable levels of N -desmethylclozapine, clozapine -N -oxide, clozapine-5 N -glucuronide, or clozapine- N + - glucuronide. Patients comedicated with cytochrome P450 enzyme inducers, inhibitors, or valproic acid were excluded. The high-resolution mass spectrometry assay enabled detection of 21 clozapine metabolites. Metabolite profiles were compared between patients switching treatment (switchers), measured as clozapine being replaced by another antipsychotic drug in blood samples, versus maintaining clozapine treatment (nonswitchers) during the study period.

FINDINGS/RESULTS

Of the 84 patients fulfilling the study criteria, 7 patients (8.3%) were identified as clozapine switchers. After correcting for smoking habits, the clozapine-5 N -glucuronide/clozapine ratio was 69% lower ( P < 0.001), while the clozapine- N + -glucuronide/clozapine-5 N -glucuronide ratio was 143% higher ( P = 0.026), respectively, in switchers versus nonswitchers. The other metabolite ratios did not significantly differ between switchers and nonswitchers.

IMPLICATIONS/CONCLUSIONS

The present study found a significantly reduced 5 N -glucuronidation phenotype in patients switching from clozapine at therapeutic serum concentrations (>1070 nmol/L) to other antipsychotic drugs. This may indicate that glucuronidation, as a potential detoxification mechanism, is related to clozapine tolerability. However, the causality of this observation needs to be investigated in future studies with larger patient populations.

Clozapine- and non-clozapine-associated neutropenia in patients with schizophrenia: a retrospective cohort study

INTRODUCTION

The antipsychotic drug clozapine remains underutilized partly because of the risk of life-threatening adverse effects, such as neutropenia. Therefore, an extensive hematological monitoring program was set up to detect neutropenia.

METHODS

In this retrospective cohort study, we used registry-based data from the Capital Region of Denmark to investigate incidence rates of neutropenia among patients with a diagnosis of schizophrenia or other psychotic disorders and treated with clozapine for the first time. In a within-subject design, we compared rates of neutropenia in time periods where patients were exposed to clozapine versus time periods, where they were not exposed to clozapine. We also investigated whether the lengths of clozapine-associated neutropenia (CAN) were related to discontinuation of clozapine treatment.

RESULTS

Data from 520 clozapine users were included. The incidence rate of CAN was 3.2 cases per 100 person-years (95% confidence interval [CI]: 2.1-4.8) throughout the entire study. There was no significant difference in incidence rates of neutropenia during clozapine exposure and non-clozapine exposure, with an incidence rate ratio of 0.7 (95% CI: 0.4-1.3). One episode of severe neutropenia was detected. Episodes of CAN with only one sub-threshold neutrophil count were not associated with higher clozapine discontinuation (26%) than CAN episodes of more than one sub-threshold neutrophil count (28%).

CONCLUSION

In the present study, we could not confirm that clozapine treatment was associated with neutropenia.

Clinical predictors of response to clozapine in Tunisian patients with treatment resistant schizophrenia

INTRODUCTION

Treatment resistant schizophrenia (TRS), affecting approximately one-third of patients with schizophrenia, is associated with a serious impairment in global psychosocial functioning. Clozapine is the only licensed drug for TRS. However its prescription remains limited by its side effects requiring mandatory monitoring. The need to identify clinical factors associated with good response to clozapine in TRS has been established. The presence of ethnic differences in these factors and the scarcity of data on the Tunisian or more generally the North-African population warrants the conduct of a clinical study on the subject. The aim of this study was to investigate demographic, clinical, and biochemical patient characteristics as potential predictors of response to clozapine.

METHODS

This is a cross-sectional and retrospective study, at the "F and A psychiatry departments" of Razi Hospital in Manouba, Tunisia. All patients, with DSM 5 diagnosis of schizophrenia in its resistant form, on clozapine for at least 12 months and who consulted from June 1, 2018 to November 30, 2018 were included. We investigated premorbid functioning by the premorbid adjusment scale, demographic and clinical characteristics, and clozapine plasma level as potential clozapine response predictors. The response to clozapine was defined by a total BPRS score of 35 or less.

RESULTS

Sixty-three patients were included in the study. The mean age at clozapine introduction was 30,84 ±9,25 years. The mean duration of clozapine treatment was 7,22 ± 4,02 years. There were 16 clozapine responders (25%) who had BPRS total scores below or equal to 35 and 47 non-responders (75%). A higher premorbid social functioning in childhood (p = 0,018) and early adolescence (p = 0,024) was associated with better response to clozapine. A delay clozapine initiation shorter than 7 years(p = 0,036), one atypical antipsychotic trial (p = 0,029) and schizophrenia paranoid subtype (p< 0.01) were found to be significantly predictive of good clozapine response. None of the demographic factors or biochemical characteristics were associated with clozapine response.

CONCLUSIONS

Our work is consistent with previous studies suggesting the need for clinicians to be aware of the clinical predictors of a good response to clozapine to overcome their reluctance to prescribe it. It also highlighted the major prognostic role of premorbid adjustment in the clinical response to treatment. However, prospective studies including therapeutic drug monitoring would be very useful to better delineate the sub-group of patients to whom clozapine would benefit the most and to improve prescription modalities.

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.

Reducing the Risk of Withdrawal Symptoms and Relapse Following Clozapine Discontinuation-Is It Feasible to Develop Evidence-Based Guidelines?

Clozapine is the only antipsychotic that is effective in treatment-resistant schizophrenia. However, in certain clinical situations, such as the emergence of serious adverse effects, it is necessary to discontinue clozapine. Stopping clozapine treatment poses a particular challenge due to the risk of psychotic relapse, as well as the development of withdrawal symptoms. Despite these challenges for the clinician, there is currently no formal guidance on how to safely to discontinue clozapine. We assessed the feasibility of developing evidence-based recommendations for (1) minimizing the risk of withdrawal symptoms, (2) managing withdrawal phenomena, and (3) commencing alternatives treatment when clozapine is discontinued. We then evaluated the recommendations against the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. We produced 19 recommendations. The majority of these recommendation were evidence-based, although the strength of some recommendations was limited by a reliance of studies of medium to low quality. We discuss next steps in the refinement and validation of an evidence-based guideline for stopping clozapine and identify key outstanding questions.

Safety profile of clozapine: Analysis using national registry data in Japan

Clozapine is the only effective antipsychotic drug used for the treatment of treatment-resistant schizophrenia. Although it has been shown that the frequency of clozapine use is very low in Japan, our previous study revealed that the number of clozapine prescriptions has been increasing in recent years, and that risk factors leading to discontinuation of clozapine were also identified as age ≥40 years, poor tolerability to olanzapine, previous treatment with clozapine, and white blood cell count <6000/mm³. The main cause for discontinuation of clozapine is the occurrence of a wide range of adverse events, including neutropenia/leukopenia and fatal cardiac disorders. In this study, we analyzed the physical details and backgrounds of patients with adverse events that led to clozapine discontinuation using a national registry database of more than 8000 Japanese patients. The physical adverse events that led to discontinuation of clozapine were neutropenia/leukopenia, glucose intolerance, cardiac disorders, gastrointestinal disorders, neuroleptic malignant syndrome, pleurisy, pulmonary embolism, sedation/somnolence, and seizures. Neutropenia/leukopenia had the highest incidence (5.0%). Neutropenia/leukopenia and cardiac disorders tended to occur early in the treatment period, indicating the need for careful monitoring for these adverse events in the early stages of clozapine treatment. Gastrointestinal disorders occurred over a long period of time, suggesting the need for careful observation during the maintenance period. The data obtained in our study will lead to the optimal and safe use of clozapine treatment.

Risk factors for early-phase clozapine discontinuation: A nested case-control study

OBJECTIVES

Safe and efficient methods for introducing clozapine to patients with treatment-resistant schizophrenia (TRS) are needed. We investigated risk factors for clozapine discontinuation in the early phase of its introduction.

METHODS

We conducted a nested case-control study at 14 psychiatric hospitals in Chiba, Japan. Data from pre-registered TRS patients were collected at 7 time points within 12 weeks before and after the start of clozapine introduction. We examined the demographic data, prior and concomitant psychotropic drugs, strategies for switching from prior antipsychotics, and blood test and Global Assessment of Function results. The Clinical Global Impression-Severity Scale was retrospectively scored at 12 weeks before and after clozapine introduction.

RESULTS

Of 228 patients, clozapine treatment was continued in 213 (93.4 %) and discontinued in 15 (6.6 %) patients within 12 weeks. Clinical symptoms were improved to mild symptoms with a response rate of 14.9 %. Prior antipsychotics and concomitant psychotropic drugs except for mood stabilizers were significantly decreased. Histories of smoking (OR = 3.32, 95 %CI: 1.11-9.93) and antipsychotic treatment at chlorpromazine-equivalent doses <1200 mg within the past 5 years (OR = 3.93, 95 %CI: 1.24-12.50), but not antipsychotic switching strategy, were associated with clozapine discontinuation. Eosinophilia was the most frequent reason for discontinuation (n = 3, 20 %) and was associated with concomitant valproate at 4 weeks after the introduction.

CONCLUSION

Clozapine is an effective option for TRS patients (especially those treated with higher doses of prior antipsychotics) in Japan. Clinicians should be cautious about concomitant valproate in the early phase of clozapine introduction due to a high risk of eosinophilia.

Clinical outcomes after clozapine discontinuation in responders versus nonresponders: a retrospective chart review

No studies have compared clinical outcomes after discontinuation of clozapine between patients who responded to clozapine and those who did not. Therefore, we examined 1-year clinical outcomes after clozapine discontinuation in responders and nonresponders. We reviewed data on patients who discontinued clozapine and retrospectively followed them for 1 year. Clinical information was collected from medical records starting at the initiation of clozapine administration, at discontinuation and at 1 year after discontinuation. In addition, clinical status was assessed using the Clinical Global Impression - Severity (CGI-S) and Clinical Global Impression - Improvement (CGI-I) scales. We classified the patients into clozapine responder and nonresponder groups according to the CGI-I score. Thirty-nine patients were enrolled in this study. Olanzapine was the most common antipsychotic prescribed after clozapine discontinuation in both the responder and nonresponder groups. The mean CGI-S score significantly increased 1 year after clozapine discontinuation in the responder group and significantly decreased in the nonresponder group; there was a significant difference in changes in the CGI-S scores between the groups. The difference remained significant after controlling for clozapine dose and duration of treatment. The findings suggest that clinicians may consider continuing and discontinuing clozapine treatment for patients who responded to clozapine and those who did not, respectively.

Predictors of discontinuation and hospitalization during long-acting injectable antipsychotic treatment in patients with schizophrenia spectrum disorder

The aim of this study was to evaluate discontinuation and hospitalization rates in patients with schizophrenia spectrum disorder who were treated with long-acting injectable (LAI) antipsychotics. We recorded clinical data about the period before the LAI treatment, when LAI treatment was initiated, and during the LAI treatment. Variables related to early (<8 weeks) and other LAI discontinuations and hospitalization were analyzed. Out of 452 patients, 14.4% of them discontinued their LAI treatment before 8 weeks, another 24.8% of the patients stopped their LAI by themselves later. Early discontinuers were younger, had shorter duration of illness, and less educated. Sixty-two (27.2%) of the patients were hospitalized under LAI treatment and 40% of the hospitalizations occurred in initial 6 months. Rate of hospitalization was 36.1% in the group who discontinued LAI after 8 weeks. In logistic regression analysis, younger age, history of combined antipsychotic treatment, number of hospitalizations before LAI, use of LAI for less than 6 months and alcohol abuse under LAI treatment were found related to hospitalization. Our findings suggested that discontinuation and hospitalization are still common among the patients who were treated with LAI antipsychotics.

Clozapine tolerability in Treatment Resistant Schizophrenia: exploring the role of sex

Clozapine is the only evidence-based drug indicated for Treatment Resistant Schizophrenia but it is largely underprescribed, partially due to its life-threatening adverse effects (AEs). However, clozapine treatment is burdened by other common AEs as constipation, hypersalivation, postural hypotension, tachycardia and metabolic abnormalities. Few studies have investigated sex-related differences in clozapine's tolerability, reporting women to experience more frequently weight gain, hyperglycemia and constipation, while men hypertension and dyslipidemia. Based on these premises, we investigated clinical, psychopathological and metabolic sex-related differences among 147 treatment-resistant patients treated with clozapine, with a specific focus on non-life-threatening AEs. We observed significant higher prevalence of tachycardia in men, and of orthostatic hypotension and constipation in women. Concerning metabolic alterations, we observed significant lower levels of HDL-cholesterol and higher prevalence of hypertriglyceridemia among men, whereas females showed higher prevalence of abdominal obesity. Consistently with previous studies, our data confirm the presence of sex-related differences in clozapine tolerability, with a main effect of sex especially for tachycardia, postural hypotension and constipation. Although non-life-threatening, these common AEs significantly affect patients' quality of life, undermine compliance and cause treatment discontinuation. A better understanding of this topic could contribute to tailor therapeutic approaches, thus improving tolerability, compliance and clinical stability.

Demographic and clinical variables associated with response to clozapine in schizophrenia: a systematic review and meta-analysis

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.

Absolute and Dose-Adjusted Serum Concentrations of Clozapine in Patients Switching vs. Maintaining Treatment: An Observational Study of 1979 Patients

BACKGROUND

Clozapine is an effective drug for the management of schizophrenia that has not responded to other agents, but some patients experience insufficient or adverse effects and discontinue treatment.

OBJECTIVE

We investigated a potential association between clozapine serum concentrations and switching to other antipsychotics in a large real-world patient population from a therapeutic drug monitoring service.

METHODS

Absolute and dose-adjusted serum concentrations (concentration-to-dose ratios [C/D ratios]) of clozapine during dosing between 100 and 1000 mg/day were measured in 1979 Norwegian patients during the period 2005-2019. These variables were compared in patients switching to other antipsychotic drugs versus maintaining clozapine treatment using linear mixed models. Smoking habits were known for 49% of the patients. To prevent potential nonadherence affecting clozapine switching, only patients with serum concentrations above 50% of the lower reference range were included.

RESULTS

In total, 190 patients (9.6%) switched from clozapine to another antipsychotic drug during the study period, whereas the remaining patients were not detected as switchers and were interpreted as maintaining treatment. Patients switching treatment had 23.5% lower absolute concentrations (954 vs. 1245 nmol/L; p < 0.001) and 15.7% lower daily doses (305 vs. 362 mg/day; p < 0.001) of clozapine than did nonswitchers, making the clozapine C/D ratio 9.7% lower in switchers than in nonswitchers after correcting for smoking habits (2.80 vs. 3.10 nmol/L/mg/day; p = 0.032).

CONCLUSIONS

The present study suggests that decreased absolute and dose-adjusted serum concentrations of clozapine were associated with clozapine discontinuation. The significantly reduced clozapine concentrations regardless of prescribed dose in switchers versus nonswitchers may indicate a pharmacokinetic mechanism underlying the risk of clozapine discontinuation.

Adherence to clozapine vs. other antipsychotics in schizophrenia

BACKGROUND

To date, there have been no studies evaluating adherence to clozapine with electronic adherence monitoring (EAM) such as the Medication Event Monitoring System (MEMS^® ).

METHODS

In outpatients with schizophrenia, we conducted a 3-month prospective study investigating antipsychotic adherence with EAM (eCAP^® ). Participants were treated with different oral antipsychotics, including clozapine, and blind to EAM monitoring; all were on antipsychotic monotherapy administered once daily. Outcome measures included adherence rate, missed dose, and medication gap. Adherence trajectory patterns were also analyzed for clozapine vs. other antipsychotics collectively.

RESULTS

A total of 111 patients were included in the study; 33 and 78 patients received clozapine or other antipsychotics, respectively. Adherence rates, defined as proportion of days that the subject took the medication at the prescribed time ± 3 h and proportion of subjects with ≥80% adherence, were numerically higher in patients receiving clozapine vs. other antipsychotics (72.0% vs. 65.1%, P = 0.10; 49.5% vs. 35.7%, P = 0.11, respectively). Along similar lines, some of the missed dose and medication gap outcomes were significantly better in patients receiving clozapine vs. other antipsychotics. Three adherence trajectory patterns were identified for both clozapine and other antipsychotics, with two shared by both groups (i.e., low adherence with a slight decrease over time; high and stable adherence).

CONCLUSION

Findings suggest that in patients with schizophrenia clozapine adherence is at least comparable, if not slightly better, compared with other antipsychotics.

Clozapine use - has practice changed?

BACKGROUND

One-third of individuals with schizophrenia have treatment-resistant illness. Of these, up to 60% will respond to clozapine treatment.

AIMS

This study retrospectively examined clozapine prescribing patterns against National Institute for Health and Care Excellence (NICE) guidelines as treatment-resistant illness emerged in a first-episode psychosis cohort.

METHODS

A total of 339 individuals with a first-episode psychosis were included in the study. Clozapine prescribing patterns were compared against the NICE guidelines and the impact of clozapine use on one index of service utilisation (hospitalisation) was assessed.

RESULTS

A total of 32 individuals (9.4%) from the cohort were prescribed clozapine. The mean time to clozapine trial was 2.1 years (SD 1.95; range 0.17-6.25). The mean number of adequate trials of antipsychotic prior to starting clozapine was 2.74 (SD 1.13; range 1-5). Following clozapine initiation, mean hospital admissions per year reduced from 2.3 to 0.3 (p=0.00). Mean hospital days pre- and post-clozapine also reduced (147 vs. 53; p=0.00). In total, 18 patients discontinued clozapine use during follow-up - 5 temporarily and 13 permanently.

CONCLUSIONS

Patients are being prescribed clozapine earlier than previously demonstrated, though delays are still evident, and many patients discontinue treatment. More work needs to be undertaken to understand and address factors which lead to its discontinuation.

A case report on clozapine-induced ventricular ectopics: a fatal adverse drug reaction

Background Clozapine is one of the most efficacious antipsychotic drug used for the treatment-resistant schizophrenia; it is sometimes associated with serious adverse reactions like agranulocytosis, myocarditis, cardiac rhythm disturbances, etc. Case presentation A 30-year-old patient with a primary diagnosis of paranoid schizophrenia (ICD code - F20.05) was on regular prescription for 6 years. Due to refractoriness, the patient was initiated on tablet clozapine. After 45 days of clozapine therapy, he presented with the complaints of worsening of positive symptoms and sudden falls associated with a brief period of unresponsiveness for which the patient was admitted for evaluation. After stabilization of the patient, it was concluded that he was suffering from ventricular ectopics based upon cardiac investigations like electrocardiogram (ECG) and Holter monitoring. Upon causality assessment between the adverse drug reaction (ADR) and the suspected drug using Naranjo Scale and WHO causality assessment scale, the ADR was found to be probable. Conclusions This case report will help to keep physicians vigilant about the rare cardiac side effects of clozapine and to do regular ECG monitoring of the patients who are on clozapine. Moreover, this case report generates the evidence of clozapine-induced arrhythmia, which is needed to be quantified with aggressive study design and there is a need to study the dose-dependent relationship of clozapine-induced arrhythmia.