International trends in clozapine use: a study in 17 countries

Clozapine use at a specialised psychiatric hospital in Johannesburg

Background

Clozapine is the gold standard medication for treatment-resistant psychosis, with robust evidence supporting its efficacy in multiple symptom domains. However, clozapine's side effect profile contributes to its underutilisation and discontinuation.

Aim

This study aimed to explore the magnitude of clozapine use and describe factors that impact on its effective use among in-patients.

Setting

Tara Hospital, a specialised psychiatric hospital in Johannesburg.

Methods

This was a retrospective, cross-sectional file review of clozapine-treated patients admitted over the 2-year study period. Data variables included: demographics, clinical information, discharge prescription, clozapine-related side effects and details of clozapine discontinuation, where applicable.

Results

A cohort of 33.2% of patients from Tara's biological wards received a trial of clozapine. Participants experienced anti-cholinergic clozapine-related side effects that included weight gain (79.5%), tachycardia (35.2%) and constipation (35.2%). Clozapine was discontinued in 13.7% of participants, and no life-threatening side effects or deaths occurred. Significantly more use of flupenthixol decanoate (64.3% vs. 30.7%; p = 0.0322) and anticholinergics (35.7% vs. 11.4%; p = 0.0474) occurred in the clozapine-discontinued group. Polypharmacy rates were high for psychiatric and non-psychiatric medications.

Conclusion

One-third of patients received clozapine trials, most of whom continued at discharge. Although side effects occurred frequently, life-threatening side effects did not. Clozapine monitoring protocols, side effect rating scales, pre-emptive management of side effects, lifestyle interventions and clinician education may improve outcomes of clozapine use. The use of plasma clozapine levels may be beneficial.

Contribution

This study expands our limited knowledge regarding current clozapine prescribing trends in South Africa.

Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia

Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.

Clozapine haematological monitoring for neutropenia: a global perspective

AIMS

Clozapine is licensed for treatment-resistant psychosis and remains underutilised. This may berelated to the stringent haematological monitoring requirements that are mandatory in most countries. We aimed to compare guidelines internationally and develop a novel Stringency Index. We hypothesised that the most stringent countries would have increased healthcare costs and reduced prescription rates.

METHOD

We conducted a literature review and survey of guidelines internationally. Guideline identification involved a literature review and consultation with clinical academics. We focused on the haematological monitoring parameters, frequency and thresholds for discontinuation and rechallenge after suspected clozapine-induced neutropenia. In addition, indicators reflecting monitoring guideline stringency were scored and visualised using a choropleth map. We developed a Stringency Index with an international panel of clozapine experts, through a modified-Delphi-survey. The Stringency Index was compared to health expenditure per-capita and clozapine prescription per 100 000 persons.

RESULTS

One hundred twocountries were included, from Europe (n = 35), Asia (n = 24), Africa (n = 20), South America (n = 11), North America (n = 7) and Oceania and Australia (n = 5). Guidelines differed in frequency of haematological monitoring and discontinuation thresholds. Overall, 5% of included countries had explicit guidelines for clozapine-rechallenge and 40% explicitly prohibited clozapine-rechallenge. Furthermore, 7% of included countries had modified discontinuation thresholds for benign ethnic neutropenia. None of the guidelines specified how long haematological monitoring should continue. The most stringent guidelines were in Europe, and the least stringent were in Africa and South America. There was a positive association (r = 0.43, p < 0.001) between a country's Stringency Index and healthcare expenditure per capita.

CONCLUSIONS

Recommendations on how haematological function should be monitored in patients treated with clozapine vary considerably between countries. It would be useful to standardise guidelines on haematological monitoring worldwide.

The Modernization of Clozapine: A Recapitulation of the Past in the United States and the View Forward

PURPOSE

Although clozapine was Food and Drug Administration (FDA) approved more than 3 decades ago, major barriers and gaps in knowledge continue to prevent its effective and safe use. We review modern-day problems encountered with clozapine in the United States (US).

METHODS

Information surrounding current administrative, clinical, research, and technological gaps or barriers related to clozapine use in the US was reviewed.

FINDINGS

The history of how clozapine became FDA approved likely contributes to gaps in knowledge. The frequency of safety warnings added to the FDA prescribing information may add to fears about clozapine, as evidence by numerous published survey studies. The clozapine Risk Evaluation and Mitigation Strategy (REMS) program has been modified several times in the last decade, causing access and safety issues for patients, which are discussed. Evidence may suggest that the FDA REMS requirements for hematologic monitoring are too cumbersome, and there may be ability to safely loosen requirements. The COVID-19 pandemic brought forth the ability for extended interval monitoring but also greater awareness of the clozapine-inflammation interaction. Newer guidelines published describe considerations in personalizing clozapine titration based on principles of ethnopsychopharmacology. Emerging technologies to support the use of clozapine are not widely available.

IMPLICATIONS

Clozapine is a unique life-saving drug but it is underused in the US, despite its established efficacy. The 2021 REMS changes led to significant difficulties for providers and patients. We highlight the importance of the clozapine-inflammation interaction, therapeutic drug monitoring, and the ability for individual care based on patient-specific factors. There is an urgent need for advancing technology used for clozapine monitoring, evaluating barriers created by REMS, and establishing consistent practices throughout the US.

Combination of strategies to initiate clozapine for refractory schizophrenia in a patient with low neutrophil levels

Clozapine is the only drug with confirmed efficacy for refractory schizophrenia; however, its use is restricted due to the risk of potentially life-threatening side effects, such as agranulocytosis. Although this restriction ensures safety against haematological risks, some patients with refractory schizophrenia who have low neutrophil levels may miss the opportunity to receive clozapine treatment. We herein report the case of a patient with refractory schizophrenia and low neutrophil levels who was successfully initiated on clozapine treatment after the use of several methods for increasing neutrophil levels. These strategies consisted of discontinuation of antipsychotics, treatment with lithium carbonate and adenine, and light exercise before blood testing. Combining these procedures may be an effective option in the treatment of patients with refractory schizophrenia whose neutrophil levels are not sufficient to initiate clozapine.

Antipsychotic utilisation and persistence in Australia: A nationwide 5-year study

OBJECTIVES

To evaluate the utilisation and persistence of antipsychotics for the treatment of schizophrenia in Australia.

METHODS

A retrospective study using the Australian Pharmaceutical Benefits Scheme database of a representative 10% sample. All adults with schizophrenia who were dispensed three or more supplies of oral (including clozapine) or long-acting injectable antipsychotics between 1 June 2015 and 31 May 2020 were included. Persistence time in treatment was evaluated using survival analysis and Cox hazard ratios.

RESULTS

In all, 26,847 adults with schizophrenia were studied. Oral second-generation antipsychotics were more frequently dispensed than the other antipsychotic groups studied. Median treatment persistence times were 18.3 months for second-generation antipsychotic long-acting injectables, 10.7 months for oral second-generation antipsychotics and were significantly lower for both formulations of first-generation antipsychotics at 5.2 months (long-acting injectables) and 3.7 months (oral). The median persistence time for clozapine was significantly longer than all other antipsychotics groups.

CONCLUSIONS

Oral second-generation antipsychotics and second-generation antipsychotic long-acting injectables accounted for over 75% and 13% of all antipsychotics in Australia, respectively. Concerns over medication adherence and subsequent relapse have not translated into increased long-acting injectable usage despite their significantly longer persistence. Clozapine, the single most 'persistent' antipsychotic, was only used in 9% of people, although up to a third of all cases are likely to be treatment-resistant. Our data suggest clinicians should give consideration to the earlier use of second-generation antipsychotic long-acting injectables and clozapine, to ameliorate prognosis in schizophrenia.

Relaxation of the criteria for entry to the UK Clozapine Central Non-Rechallenge Database: a modelling study

BACKGROUND

Clozapine is uniquely effective in treatment-resistant psychosis. In the UK, patients must discontinue clozapine indefinitely if they are placed on the Central Non-Rechallenge Database (CNRD) after their haematological parameters fall below particular thresholds. Under exceptional circumstances, patients can be rechallenged on clozapine under an off-licence agreement. In the USA in 2015, restrictive practice was discontinued to allow greater flexibility for clozapine maintenance. The absolute neutrophil count leading to treatment interruption was lowered from less than 1·5 × 10⁹/L to less than 1·0 × 10⁹/L and platelet and white cell count monitoring were ceased. We aimed to investigate the implications of a similar policy change on clozapine use in the UK.

METHODS

This was a modelling study of all patients registered on the UK CNRD. First, we determined the proportion of patients placed on the database in the UK who would have had to discontinue clozapine treatment under the US Food and Drug Administration (FDA) criteria. Second, we compared the haematological characteristics of patients who did or did not meet FDA criteria for discontinuing clozapine, including the time to registration from clozapine initiation and the proportion of cases of severe neutropenia at registration. Third, we investigated the success rates of clozapine re-challenge for patients that had been placed on the CNRD. Successful rechallenge was defined as no recurrence of CNRD registration.

FINDINGS

Between May 2, 2002 and March 1, 2021, 3731 patients were placed on the CNRD, with a mean age of 47 years (SD 15), including 1420 (38%) women and 2311 (62%) men, of whom 3089 (83%) were White, 360 (10%) were Black, 190 (5%) were Asian, and 92 (2%) were classified as other. 566 (15%) of 3731 patients met the equivalent criteria for clozapine discontinuation under the FDA guidelines. The median time to CNRD registration from clozapine initiation was 1·6 years (IQR 0·2-4·9). Data for 519 rechallenged patients were examined; 419 (81%) were successful. Clozapine rechallenge success rates were broadly similar between individuals who did not meet the US CNRD registration criteria (36 [78%] of 46) and those who did meet the criteria (383 [81%] of 473).

INTERPRETATION

Implementing the revised FDA monitoring criteria in the UK would substantially reduce clozapine discontinuation for haematological reasons, which would greatly improve the mental health outcomes of these patients without having a major effect on their physical health.

FUNDING

None.

An Updated Analysis of Psychotropic Medicine Utilisation in Older People in New Zealand from 2005 to 2019

BACKGROUND

Psychotropic medicine utilisation in older adults continues to be of interest because of overuse and concerns surrounding its safety and efficacy.

OBJECTIVE

This study aimed to characterise the utilisation of psychotropic medicines in older people in New Zealand.

METHODS

We conducted a repeated cross-sectional analysis of national dispensing data from 1 January, 2005 to 31 December, 2019. We defined utilisation using the Anatomical Therapeutic Chemical classification defined daily dose system. Utilisation was measured in terms of the defined daily dose (DDD) per 1000 older people per day (TOPD).

RESULTS

Overall, the utilisation of psychotropic medicines increased marginally by 0.42% between 2005 and 2019. The utilisation increased for antidepressants (72.42 to 75.21 DDD/TOPD) and antipsychotics (6.06-19.04 DDD/TOPD). In contrast, the utilisation of hypnotics and sedatives (53.74-38.90 DDD/TOPD) and anxiolytics decreased (10.20-9.87 DDD/TOPD). The utilisation of atypical antipsychotics increased (4.06-18.72 DDD/TOPD), with the highest percentage change in DDD/TOPD contributed by olanzapine (520.6 %). In comparison, utilisation of typical antipsychotics was relatively stable (2.00-2.06 DDD/TOPD). The utilisation of venlafaxine increased remarkably by 5.7 times between 2005 and 2019. The utilisation of zopiclone was far greater than that of other hypnotics in 2019.

CONCLUSIONS

There was only a marginal increase in psychotropic medicines utilisation from 2005 to 2019 in older adults in New Zealand. There was a five-fold increase in the utilisation of antipsychotic medicines. Continued monitoring of psychotropic medicine utilisation will be of interest to understand the utilisation of antidepressants and antipsychotic medicines during the coronavirus disease 2019 pandemic year.

Clozapine prescribing practice and trends in Qatar: First national observational study

BACKGROUND

Clozapine is the gold standard in the management of treatment-resistant schizophrenia. Despite its clinically proven efficacy clozapine utilization is variable globally and published evidence is suggestive of its underutilization. Research from the Arab region on clozapine utilization is limited. The aim of our descriptive observational study was to evaluate the prescribing practice of clozapine and its sociodemographic and clinical corelates in the State of Qatar.

METHODS

The study is a retrospective case-note review of all patients maintained on clozapine, in the calendar year 2020. Data were collected on sociodemographic characteristics of the patients; antipsychotic trials before initiating clozapine; and clinical characteristics of the patients, including their diagnoses leading to prescription of clozapine, duration of illness, psychiatric hospitalizations, and co-morbidities.

RESULTS

During the study period, 100 patients were maintained on clozapine. Patients were mostly Qatari and non-Qatari Arab males. Prescription rates were significantly different for Qatari patients when compared to non-Qatari patients. Most patients had a chronic illness with the age of onset of illness in early adulthood and were diagnosed with schizophrenia or schizoaffective disorder. The mean daily dose of clozapine was 325 mg. Eighty percent of the patients received two or more antipsychotic trials before initiating clozapine. Sixty-eight percent of the patients had more than two antipsychotic trials before initiating Clozapine. One third of patients had no history of psychiatric hospitalizations, and one quarter had five or more previous psychiatric hospitalizations. Of the psychiatric comorbidities, mood and substance use disorders were common. Of medical comorbidities, endocrine and metabolic disorders were common.

CONCLUSION

Despite apparent underutilization, the Clozapine prescribing rates in Qatar are comparable to countries with plasma monitoring systems when framed within Qatar's unique demographic context. However, there still is a significant delay in Clozapine initiation despite its clinical superiority.

STRENGTHS AND LIMITATIONS OF THIS STUDY

First study on Clozapine utilization from the Middle-East and North-Africa region. This study examined prescribing of clozapine in a national cohort of patients in Qatar. Provides insight into sociodemographic and clinical correlates of clozapine prescribing in a country with 90% migrants. Limited by the completeness of the information contained in the patients' medical charts.

A Guideline and Checklist for Initiating and Managing Clozapine Treatment in Patients with Treatment-Resistant Schizophrenia

Treatment-resistant schizophrenia (TRS) will affect about one in three patients with schizophrenia. Clozapine is the only treatment approved for TRS, and patients should be treated as soon as possible to improve their chances of achieving remission. Despite its effectiveness, concern over side effects, monitoring requirements, and inexperience with prescribing often result in long delays that can expose patients to unnecessary risks and compromise their chances of achieving favorable long-term outcomes. We critically reviewed the literature on clozapine use in TRS, focusing on guidelines, systematic reviews, and algorithms to identify strategies for improving clozapine safety and tolerability. Based on this, we have provided an overview of strategies to support early initiation of clozapine in patients with TRS based on the latest evidence and our clinical experience, and have summarized the key elements in a practical, evidence-based checklist for identifying and managing patients with TRS, with the aim of increasing confidence in prescribing and monitoring clozapine therapy.

Clozapine Treatment Is Associated With Higher Prescription Rate of Antipsychotic Monotherapy and Lower Prescription Rate of Other Concomitant Psychotropics: A Real-World Nationwide Study

BACKGROUND

Although clozapine is effective for treatment-resistant schizophrenia (TRS), the rate of clozapine prescription is still low. Whereas antipsychotic monotherapy is recommended in clinical practice guidelines, the rate of antipsychotic polypharmacy is still high. There is little evidence on whether a clozapine prescription influences changes in the rate of monotherapy and polypharmacy, including antipsychotics and other psychotropics. We therefore hypothesized that the rate of antipsychotic monotherapy in patients with TRS who were prescribed clozapine would be higher than that in patients with schizophrenia who were not prescribed clozapine.

METHODS

We assessed 8306 patients with schizophrenia nationwide from 178 institutions in Japan from 2016 to 2019. We analyzed the psychotropic prescription data at discharge in patients diagnosed with TRS and with no description of TRS (ND-TRS) based on the diagnosis listed in the discharge summary.

RESULTS

The rate of antipsychotic monotherapy in the TRS with clozapine group (91.3%) was significantly higher than that in the TRS without clozapine group (45.9%; P &lt; 2.0 × 10-16) and the ND-TRS without clozapine group (54.7%; P &lt; 2.0 × 10-16). The rate of antipsychotic monotherapy without any other concomitant psychotropics in the TRS with clozapine group (26.5%) was significantly higher than that in the TRS without clozapine group (12.6%; P = 1.1 × 10-6) and the ND-TRS without clozapine group (17.0%; P = 5.9 × 10-6).

CONCLUSIONS

Clozapine prescription could be associated with a high rate of antipsychotic monotherapy. Patients will benefit from the correct diagnosis of TRS and thus from proper clozapine prescription.

The pharmacological treatment of schizophrenia: How far have we come?

Schizophrenia is a chronic and often severe mental disorder for which antipsychotic drugs are the cornerstone of treatment. Although the essential mechanism of action of these drugs has not changed much since they were first discovered in the 1950s, there have been numerous advances in the context in which these drugs are prescribed, as well as in the considerations for their optimal use. In this review, we summarize five selected issues in which the psychopharmacological treatment of schizophrenia has most evolved. Namely, these are the shift of outcomes of interest from symptoms to recovery, the development of stratified approaches to select the most appropriate treatment for each individual, the recognition of treatment nonadherence as a critical factor determining outcomes, the recommendations for maintenance treatment, and, finally, the promise of new antipsychotic compounds that innovate in their mechanisms of action, improving efficacy/safety profiles. Finally, we discuss how some of these advances have already delivered to improved outcomes in the real world, whereas others have demonstrated efficacy under optimal circumstances yet have not been translated into better outcomes in the community. Thus, the road ahead includes both identifying novel treatments that engage the psychopathology of the illness and improve the efficacy/tolerability profile of currently available agents, as well as developing interventions that mitigate the barriers for the use of novel interventions, some of them already existing, in the real world.

Neutrophil Myeloperoxidase-Mediated N-Demethylation of Quetiapine Leads to N-Desalkylquetiapine, a Pharmacologically Active Cytochrome P450 Metabolite

The atypical antipsychotic drugs, quetiapine and clozapine, are associated with idiosyncratic drug reactions (such as agranulocytosis or neutropenia) that are thought to involve reactive metabolites. Neutrophil myeloperoxidase (MPO) metabolism of quetiapine is not well-studied, but is metabolized by cytochrome P450. Based on structural similarity to clozapine, we hypothesized that quetiapine can be metabolized by MPO and that there is overlap between cytochrome P450 and MPO metabolism of quetiapine. The interaction of quetiapine and clozapine with MPO and MPO chlorination activity was studied using UV-vis spectrophotometry. The metabolites were characterized using liquid chromatography-mass spectrometry (LC-MS), and electron paramagnetic resonance (EPR) spectroscopy was used for detecting drug-catalyzed glutathione oxidation. In the presence of quetiapine, MPO compound II accumulated for about 7.5 min, whereas in the presence of clozapine, MPO compound II was not observed as it was rapidly reduced back to the resting state. Increasing quetiapine concentrations resulted in a decrease in MPO chlorination activity, while the opposite result was found in the case of clozapine. UV-vis spectral studies showed no change when quetiapine was oxidized in the absence and presence of chloride anion (Cl^-, to catalyze chlorination reactions). Significant changes, however, were observed in the same assay with clozapine, where Cl^- appeared to hinder the rate of clozapine metabolism. The MPO-catalyzed hydroxylated and dealkylated metabolites of quetiapine and hydroxylated metabolites of clozapine were observed from the LC-MS analyses, particularly when Cl^- was included in the reaction. In addition, hydroxylated, dealkylated, and a proposed sulfoxide metabolite of quetiapine were also observed in the reaction catalyzed by human microsomes/NADPH. Lastly, compared to quetiapine, clozapine metabolism by MPO/H₂O₂ and glutathione produced more glutathionyl radicals using EPR spin trapping. In conclusion, MPO/H₂O₂/Cl^- was shown to metabolize quetiapine to S-oxidation and P450-like dealkylation products, and quetiapine metabolites were generally less reactive than clozapine.

Comparative Effectiveness of Antipsychotics in Preventing Readmission for First-Admission Schizophrenia Patients in National Cohorts From 2001 to 2017 in Taiwan

BACKGROUND AND HYPOTHESIS

Antipsychotics remain the main treatment for schizophrenia, but their effectiveness is challenging to compare. We aimed to assess the comparative real-world effectiveness of antipsychotics in preventing readmission among patients in Asia with early-stage schizophrenia to inform clinical decision making.

STUDY DESIGN

We did a retrospective cohort study of first-admission schizophrenia patients (ICD-9-CM: 295; ICD-10-CM: F20 and F25) from January 1, 2001, to December 31, 2017. The cohort was identified from the National Health Insurance Research Database NHIRD for Psychiatric Inpatients. The exposure was any antipsychotics prescribed post-discharge. The primary outcome was the readmission risk due to psychotic disorders, which was measured by adjusted hazard ratios (aHRs). Within-individual extended Cox models were applied for analyses, where the periods of oral risperidone use served as his or her own control.

STUDY RESULTS

We selected 75 986 patients (men, 53.4%; mean [SD] age, 37.6 [12.0] years; mean [SD] duration of follow-up, 8.9 [5.0]) who were first admitted to psychiatric wards with schizophrenia in Taiwan. Among them, 47 150 patients (62.05%) had at least one readmission within 4 years. Compared to the period under treatment with oral risperidone, that under monotherapy with long-acting injectable antipsychotics (LAIs) had the lowest risk for psychotic readmission, with a risk reduction of 15-20%. However, the prevalence of person-prescription prevalence of LAIs remained low (< 10%) during the follow-up period.

CONCLUSIONS

The use of LAIs after the first admission for schizophrenia has notable advantages in preventing readmission. Such formulations should be offered earlier in the course of illness.

Clinical Outcomes after Clozapine Discontinuation in Patients with Schizophrenia: A Systematic Review

INTRODUCTION

Clozapine is the gold standard of treatment for patients with treatment-resistant schizophrenia. However, approximately 60% of those patients do not respond to clozapine; moreover, clinical outcomes after clozapine discontinuation are unclear so far. Therefore, we conducted a systematic review to clarify the outcomes after clozapine discontinuation.

METHODS

A systematic literature search was conducted, using MEDLINE and Embase with the following keywords: (clozapine AND (cessation* OR cease* OR withdraw* OR discontinu* OR halt* OR stop* OR switch*) AND (schizophreni* OR schizoaffective)).

RESULTS

A total of 28 clinical studies from 27 articles were identified and included in this systematic review. Three randomized controlled trials reported worsening of psychiatric symptoms. In 10 single-arm studies, the results of worsening and improving psychiatric symptoms were inconsistent. In one large retrospective cohort study, clozapine rechallenge, olanzapine, and antipsychotic polypharmacy had lower rehospitalization rates compared to no medication after clozapine discontinuation. In the other 14 retrospective studies, the vast majority showed worsening of clinical status after clozapine discontinuation. Among five studies on clinical outcomes after clozapine rechallenge, four reported improvements in clinical status in more than half of patients who rechallenged clozapine. The remaining study reported that the clozapine discontinuation-rechallenge group had a worse remission assessment score than the clozapine discontinuation-no rechallenge group.

DISCUSSION

Clinical outcomes generally worsen after clozapine discontinuation. Clozapine rechallenge and olanzapine may be considered following clozapine discontinuation. The outcomes after clozapine discontinuation in clozapine non-responders remain inconclusive; therefore, well-designed studies are warranted.

Recognition and management of clozapine adverse effects: A systematic review and qualitative synthesis

OBJECTIVE

Clozapine is substantially underutilized in most countries and clinician factors including lack of knowledge and concerns about adverse drug effects (ADEs) contribute strongly to treatment reluctance. The aim of this systematic review was to provide clinicians with a comprehensive information source regarding clozapine ADEs.

METHODS

PubMed and Embase databases were searched for English language reviews concerned with clozapine ADEs; publications identified by the automated search were manually searched for additional relevant citations. Following exclusion of redundant and irrelevant reports, pertinent information was summarized in evidence tables corresponding to each of six major ADE domains; two authors reviewed all citations for each ADE domain and summarized their content by consensus in the corresponding evidence table. This study was conducted in accordance with PRISMA principles.

RESULTS

Primary and secondary searches identified a total of 305 unique reports, of which 152 were included in the qualitative synthesis. Most clozapine ADEs emerge within 3 months, and almost all appear within 6 months, after initiation. Notable exceptions are weight gain, diabetic ketoacidosis (DKA), severe clozapine-induced gastrointestinal hypomotility (CIGH), clozapine-induced cardiomyopathy (CICM), seizures, and clozapine-induced neutropenia (CIN). Most clozapine ADEs subside gradually or respond to dose reduction; those that prompt discontinuation generally do not preclude rechallenge. Rechallenge is generally inadvisable for clozapine-induced myocarditis (CIM), CICM, and clozapine-induced agranulocytosis (CIA). Clozapine plasma levels >600-1000 μg/L appear more likely to cause certain ADEs (e.g., seizures) and, although there is no clear toxicity threshold, risk/benefit ratios are generally unfavorable above 1000 μg/L.

CONCLUSION

Clozapine ADEs rarely require discontinuation.

Long-term treatment with clozapine and other antipsychotic drugs and the risk of haematological malignancies in people with schizophrenia: a nationwide case-control and cohort study in Finland

BACKGROUND

Clozapine is the most efficacious treatment for schizophrenia and is associated with lower overall mortality than are other antipsychotic drugs, despite the risk of agranulocytosis. Preliminary reports over the past 10 years suggest a possible risk of haematological malignancies, but the issue has remained unsettled. We aimed to study the risk of haematological malignancies associated with use of clozapine and other antipsychotics.

METHODS

We did a nationwide case-control (and cohort) study of people with schizophrenia, using prospectively gathered data from Finnish national registers. A nested case-control study was constructed by individually matching cases of lymphoid and haematopoietic tissue malignancy with up to ten controls without cancer by age, sex, and time since first schizophrenia diagnosis. For the case-control study, we restricted inclusion criteria to malignancies diagnosed on a histological basis, and excluded individuals outside of the age range 18-85 years, and any patients that had a previous malignancy. Analyses were done using conditional logistic regression adjusting for comorbid conditions.

FINDINGS

For the case-control study 516 patients with a first-time diagnosis of lymphoid and haematopoietic tissue malignancy during years 2000-17 and diagnosed after their first diagnosis of schizophrenia were identified. 102 patients were excluded due to diagnosis that was without a histological basis, five patients were excluded because of their age, and 34 were excluded for a previous malignancy, resulting in 375 patients being matched to controls. We selected up to ten controls without cancer (3734 in total) for each case from the base cohort of people with schizophrenia. For the cohort study, data for 55 949 people were included for analysis. Cumulative incidence of haematological malignancies during the mean follow-up of 12·3 years (SD 6·5) was 102 (0·7%) cases among 13 712 patients who had used clozapine (corresponding to event rate of 61 cases per 100 000 person-years), and during mean follow-up of 12·9 years (SD 7·2) was 235 (0·5%) malignancies among 44 171 patients having used other antipsychotic medication than clozapine (corresponding to 41 cases per 100 000 person-years). Of the 375 individuals with haematological malignancies (305 lymphomas, 42 leukaemia, 22 myelomas, 6 unspecified) observed from 2000-17, 208 (55%) were males and 167 (45%) were female. Ethnicity data were not available. Compared with non-use of clozapine (most had used other antipsychotics and a few had used no antipsychotics), clozapine use was associated with increased odds of haematological malignancies in a dose-response manner (adjusted odds ratio 3·35, [95% CI 2·22-5·05] for ≥5000 defined daily dose cumulative exposure, p<0·0001). Exposure to other antipsychotic drugs was not associated with increased odds. A complementary analysis showed that the clozapine-related risk increase was specific for haematological malignancies, because no such finding was observed for other malignancies. Over 17 years of follow-up of the base cohort, 37 deaths occurred due to haematological malignancy among patients exposed to clozapine (26 with ongoing use at time of haematological malignancy diagnosis, and 11 in patients who did not use clozapine at the exact time of their cancer diagnosis), whereas only three deaths occurred due to agranulocytosis.

INTERPRETATION

Unlike other antipsychotics, long-term clozapine use is associated with increased odds of haematological malignancies. Long-term clozapine use has a higher effect on mortality due to lymphoma and leukaemia than due to agranulocytosis. However, acknowledging that the absolute risk is small compared with the previously observed absolute risk reduction in all-cause mortality is important. Our results suggest that patients and caregivers should be informed about warning signs of haematological malignancies, and mental health clinicians should be vigilant for signs and symptoms of haematological malignancy in patients treated with clozapine.

FUNDING

The Finnish Ministry of Social Affairs and Health and Academy of Finland.

A Comparison of Attitudes, Comfort, and Knowledge of Clozapine Among Two Diverse Samples of US Psychiatrists

Considerable variation in clozapine utilization exists across the United States, and little is known about the perspective of psychiatrists in states with low clozapine use. To better understand clozapine practices, attitudes, and barriers, a survey was administered to a group of southeastern state conference attendees (SSCA; N = 86). The same survey was administered to psychiatrists belonging to a national community psychiatry organization (AACP; N = 57), and differences were analyzed across the two samples. In comparison to the AACP, the SSCA group felt less comfortable, perceived clozapine as less safe and effective, had fewer patients on clozapine, and were more likely to prefer antipsychotic polypharmacy to clozapine use. Across the sample, use of a myocarditis screening protocol was rare (N = 14/76; 18%) and less than half used plasma antipsychotic levels to guide dosage (N = 60/129; 47%). Continuing professional education on clozapine are needed for psychiatrists who see individuals with psychotic disorders.

Distinctive pattern of neutrophil count change in clozapine-associated, life-threatening agranulocytosis

The wider use of clozapine is limited by the risk of agranulocytosis and the associated requirement for monitoring of neutrophil counts. We searched local electronic patient records for cases of agranulocytosis occurring during clozapine treatment during the period 2007–2020. We found 23 episodes recorded as agranulocytosis in clozapine patients. Of these, nine met pre-defined criteria and were considered episodes of life-threatening agranulocytosis (LTA). These episodes of clozapine-induced LTA exhibited a distinct pattern of continuous and rapid neutrophil count decline to zero or near zero. Mean time for neutrophils to fall from ANC > 2 to ANC <0.5 × 10⁹/L was 8.4 days (range 2–15 days). Each event was also characterised by a prolonged nadir and delayed recovery (range 4–16 days). Non-LTA episodes were, in contrast, brief and benign. We conclude that an important proportion of cases of agranulocytosis identified in people prescribed clozapine are not life-threatening and may not even be clozapine-related. Monitoring schemes should aim to identify true clozapine-induced LTA as opposed to threshold-defined nominal agranulocytosis. Genetics studies might benefit from examining associations with clozapine-induced LTA rather than with recorded cases of agranulocytosis or neutropenia.

Efficacy of clozapine for long-stay patients with treatment-resistant schizophrenia: 4-year observational study

Aim

Supporting patients upon discharge following prolonged hospitalization in private psychiatric hospitals in Japan have long been an issue. This study evaluated the efficacy of clozapine in treating long‐stay patients with treatment‐resistant schizophrenia to reduce the frequency and duration of readmissions postdischarge.

Methods

We retrospectively examined the length and frequency of hospitalizations of long‐stay and non‐long‐stay patients with schizophrenia who were introduced to clozapine at our hospital.

Results

Comparing participants’ medical records 2 years before and after the introduction of clozapine, we identified a significant decrease in both length and frequency of hospitalizations in all patients who were introduced to clozapine. In long‐stay patients, the length and frequency of hospitalization were significantly reduced. However, compared to non‐long‐stay patients, the period from introduction of clozapine to discharge was longer and the dose of clozapine was higher. Thus, it is necessary to take time to evaluate the therapeutic effects for long‐stay patients.

Conclusion

The results showed that clozapine is helpful for patients with treatment‐resistant schizophrenia, who are considered difficult to treat and discharge in Japan.

We retrospectively examined the length and frequency of hospitalizations of long‐stay and non‐long‐stay patients with schizophrenia who were introduced to clozapine at our hospital. Two years before and after the introduction of clozapine, we identified a significant decrease in both length and frequency of hospitalizations in all patients who were introduced to clozapine.

Rates of treatment-resistant schizophrenia from first-episode cohorts: systematic review and meta-analysis

BACKGROUND

Treatment-resistant schizophrenia (TRS) is associated with high levels of functional impairment, healthcare usage and societal costs. Cross-sectional studies may overestimate TRS rates because of selection bias.

AIMS

We aimed to quantify TRS rates by using first-episode cohorts to improve resource allocation and clozapine access.

METHOD

We undertook a systematic review of TRS rates among people with first-episode psychosis and schizophrenia, with a minimum follow-up of 8 weeks. We searched PubMed, PsycINFO, EMBASE, CINAHL and the Cochrane Database of Systematic Reviews, and meta-analysed TRS rates from included studies.

RESULTS

Twelve studies were included, totalling 11 958 participants; six studies were of high quality. The rate of TRS was 22.8% (95% CI 19.1-27.0%, P < 0.001) among all first-episode cohorts and 24.4% (95% CI 19.5-30.0%, P < 0.001) among first-episode schizophrenia cohorts. Subgroup sensitivity analyses by location of recruitment, TRS definition, study quality, time of data collection and retrospective versus prospective data collection did not lead to statistically significant differences in heterogeneity. In a meta-regression, duration of follow-up and percentage drop-out did not significantly affect the overall TRS rate. Men were 1.57 times more likely to develop TRS than women (95% CI 1.11-2.21, P = 0.010).

CONCLUSIONS

Almost a quarter of people with first-episode psychosis or schizophrenia will develop TRS in the early stages of treatment. When including people with schizophrenia who relapse despite initial response and continuous treatment, rates of TRS may be as high as a third. These high rates of TRS highlight the need for improved access to clozapine and psychosocial supports.

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.

Fatal Abdominal Compartment Syndrome Due to Constipation: A Case Report

Introduction

Abdominal compartment syndrome (ACS) is a rare condition in which increased intra-abdominal pressure causes multiorgan dysfunction through decreased perfusion. Causes of this condition are variable, and early recognition is critical for favorable patient outcomes. Measurement of bladder pressure is recommended for diagnosis.

Case Report

A 64-year-old female on clozapine with a two-year history of chronic constipation presented to the emergency department in extremis with a protuberant abdomen. After resuscitative measures, computed tomography showed a dilated, stool-filled colon with a decompressed inferior vena cava and decreased perfusion. She died despite surgical decompression.

Conclusion

Severe constipation is a rare cause of ACS, and there is a lack of evidence-based guidelines. Options for bedside decompression are limited. To reduce morbidity and mortality in this population, early recognition of ACS is imperative. Initial interventions should support hemodynamics and respiration. Definitive management is surgical decompression.

Antipsychotic-Associated Weight Gain and Clinical Improvement Under Clozapine Treatment

BACKGROUND

Antipsychotic-associated weight gain is a common adverse effect with several negative outcomes in the clinical evolution of patients, which might also affect patients' self-identity from physical appearance and imply treatment discontinuation. However, recent research has drawn attention to an unexpected clinical improvement associated with weight gain, mostly in patients under treatment with clozapine or olanzapine.

METHODS

Twenty-three treatment-resistant psychosis patients initiating clozapine were evaluated. Longitudinal psychopathological assessment through the Positive and Negative Syndrome Scale (PANSS) and anthropometric evaluation were performed at baseline, week 8, and 18.

RESULTS

Body mass index (BMI) change during clozapine treatment was associated with clinical improvement measured with PANSS total score at week 8 (P = 0.021) while showed a trend at week 18 (P = 0.058). The PANSS general score was also associated with weight gain at week 8 (P = 0.022), whereas negative subscale score showed a trend at week 8 (P = 0.088) and was associated between week 8 and 18 (P = 0.018). Sex differences applied at week 8 for PANSS total score, where clinical improvement was significantly associated with BMI in male subjects (P = 0.024). We also stratified for time to initiate clozapine, finding significant associations in negative symptom at week 8 (P = 0.023) and week 18 (P = 0.003) for subjects, which started clozapine after 3 years of illness.

CONCLUSIONS

Our results suggest that in subjects initiating clozapine, clinical improvement is associated with BMI increase, mostly in negative symptom and in patients after 3 years of antipsychotic use. Our findings were already described in the preantipsychotic era, suggesting some pathophysiological mechanism underlying both conditions.

Combination Therapy of Long-Acting Injectable Second-Generation Antipsychotics and Oral Antipsychotics: A Retrospective Chart Review and Prescribers' Attitude Survey

BACKGROUND

Although long-acting injectable antipsychotics (LAI-APs) have been considered as a monotherapeutic option in the maintenance treatment of schizophrenia, it has been recently reported that the combination therapy of LAI-APs and oral antipsychotics (OAPs) is common.

METHODS

We conducted a retrospective chart review to examine the situation of the combination therapy of LAI second-generation antipsychotics (LAI-SGAs) and OAPs, and a questionnaire survey to investigate prescribers' attitudes toward the combination therapy. We included patients who received any LAI-SGAs for 1 month or longer and classified them into monotherapy and combination therapy groups. We collected information on age, sex, primary psychiatric diagnosis, and concomitant psychotropic medications.

RESULTS

Of the 132 patients, 39 (29.5%) received the combination therapy of LAI-SGAs and OAPs. Long-acting injectable risperidone was significantly associated with receiving the combination therapy compared with LAI aripiprazole. Olanzapine was the most common OAP in combination with LAI-SGAs. Only 8 patients (20.5%) concurrently received the same type of OAPs as LAI-SGAs. More than 60% of the patients received OAP polypharmacy before the initiation of LAI-SGAs. The psychiatrists in charge prescribed LAI-SGAs mainly because of a concern about adherence, and OAPs mainly because of insufficient dose of LAI-SGAs, to patients in the combination therapy group. They estimated that adherence to OAPs in two thirds of the patients in the combination therapy group was 80% or higher.

CONCLUSIONS

The present study showed that the combination therapy of LAI-SGAs and OAPs is often conducted in real-world clinical practice. Considering the reason for the introduction of LAI-APs, clinicians should carefully monitor patients' adherence to OAPs concurrently used with LAI-APs.

Real-world effectiveness of antipsychotic treatments in 1011 acutely hospitalized patients with schizophrenia: A one-year follow-up study

PURPOSE

To compare the real-world effectiveness of antipsychotic treatments focusing on long-acting injectable antipsychotic medications (LAIs) and antipsychotic polytherapies except polytherapy involving clozapine (APEC) for patients with schizophrenia.

METHODS

This prospective study was conducted over a 19-month period in 12 psychiatric emergency hospitals in Japan. Patients who were newly admitted to psychiatric emergency wards between September 2019 and March 2020 because of acute onset or exacerbation of Schizophrenia and Other Psychotic Disorders as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were included. All patients were followed for one-year after discharge or until March 31, 2021. The primary outcome was the risk of treatment failure defined as psychiatric rehospitalization, discontinuation of medication, death, or continuation of hospitalization for one year. Cox proportional hazards multivariate regression was used for analyses.

RESULTS

A total of 1011 patients were enrolled (women, 53.7%; mean [SD] age, 47.5 [14.8] years). During follow-up, 588 patients (58.2%) experienced treatment failure including rehospitalization (513 patients), discontinuation of medication (17 patients), death (11 patients), and continuation of hospitalization for one-year (47 patients). Switching to LAIs (hazard ratio [HR] 0.810, 95%CI 0.659-0.996) and APEC (HR 0.829, 95%CI 0.695-0.990) were significantly associated with a low rate of treatment failure.

CONCLUSIONS

Switching to LAIs and APEC in early non-responders seems to be beneficial for the prevention of treatment failure in acutely admitted patients with schizophrenia. The risk of treatment failure was about 19% and 17% lower in patients treated with LAIs and APEC, respectively, than in patients treated without them.

Fatal poisonings involving clozapine: A 16-year review of Australian coronial investigations

OBJECTIVE

Concerns about intentional and unintentional poisoning present a barrier to wider use of clozapine in treatment-resistant schizophrenia. The objective of this study was to investigate decedent demographics and trends in fatal poisonings in Australia involving clozapine.

METHODS

This was a retrospective case series of all fatal drug toxicity reported to an Australian coroner between 1 May 2000 and 31 December 2016 where toxicological analysis detected clozapine. Cases were identified using the National Coronial Information System. Demographics extracted included age and gender of the decedent, year and location of death, cause and manner of death and drugs detected in post-mortem samples.

RESULTS

There were 278 poisoning deaths where clozapine was detected in toxicological analyses. Three-quarters of all cases (n = 207) involved men and the median age at death was 38.5 years (interquartile range: 16 years). Three-quarters of the deaths occurred in the home. Overall, 15.8% of deaths were deemed intentional, 57.5% unintentional and 24.5% of unknown intent. While the annual number of intentional self-poisonings remained constant with <5 per year, the overall number of fatalities increased due to an increase in unintentional poisonings. Multiple drug toxicity was reported in 55.0% of cases and clozapine alone in 45.0% of cases. The most common co-reported medications were antidepressants, benzodiazepines and opioids detected in 47.1%, 44.4% and 41.2% of multiple drug toxicities, respectively.

CONCLUSION

This was the first Australia-wide review of all fatal drug poisonings reported to a coroner involving clozapine. Fatalities were most common in men and occurred at home. Multiple drug toxicity generally involved psychotropic, sedative or opioid analgesic medications. Despite increasing clozapine use, rates of intentional poisoning have remained constant and low. Developing a better knowledge of unintentional fatalities presents an opportunity to minimise harm.

An International Adult Guideline for Making Clozapine Titration Safer by Using Six Ancestry-Based Personalized Dosing Titrations, CRP, and Clozapine Levels

This international guideline proposes improving clozapine package inserts worldwide by using ancestry-based dosing and titration. Adverse drug reaction (ADR) databases suggest that clozapine is the third most toxic drug in the United States (US), and it produces four times higher worldwide pneumonia mortality than that by agranulocytosis or myocarditis. For trough steady-state clozapine serum concentrations, the therapeutic reference range is narrow, from 350 to 600 ng/mL with the potential for toxicity and ADRs as concentrations increase. Clozapine is mainly metabolized by CYP1A2 (female non-smokers, the lowest dose; male smokers, the highest dose). Poor metabolizer status through phenotypic conversion is associated with co-prescription of inhibitors (including oral contraceptives and valproate), obesity, or inflammation with C-reactive protein (CRP) elevations. The Asian population (Pakistan to Japan) or the Americas' original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/mL. In the US, daily doses of 300-600 mg/day are recommended. Slow personalized titration may prevent early ADRs (including syncope, myocarditis, and pneumonia). This guideline defines six personalized titration schedules for inpatients: 1) ancestry from Asia or the original people from the Americas with lower metabolism (obesity or valproate) needing minimum therapeutic dosages of 75-150 mg/day, 2) ancestry from Asia or the original people from the Americas with average metabolism needing 175-300 mg/day, 3) European/Western Asian ancestry with lower metabolism (obesity or valproate) needing 100-200 mg/day, 4) European/Western Asian ancestry with average metabolism needing 250-400 mg/day, 5) in the US with ancestries other than from Asia or the original people from the Americas with lower clozapine metabolism (obesity or valproate) needing 150-300 mg/day, and 6) in the US with ancestries other than from Asia or the original people from the Americas with average clozapine metabolism needing 300-600 mg/day. Baseline and weekly CRP monitoring for at least four weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

Association between the examination rate of treatment-resistant schizophrenia and the clozapine prescription rate in a nationwide dissemination and implementation study

BACKGROUND

The decision to initiate clozapine treatment should be made on an individual basis and may be closely related to the early detection of treatment-resistant schizophrenia (TRS), although there is evidence that the early use of clozapine results in a better response to treatment. Therefore, we investigated the relationship between the examination rate of TRS and the prescription rate of clozapine.

METHODS

After attending a 1-day educational program on schizophrenia based on the "Guidelines for the Pharmacological Treatment of Schizophrenia," we asked the participating facilities to submit records of whether or not TRS was evaluated for each patient. We calculated the clozapine prescription rate from the schizophrenic patients prescribed clozapine and all of the schizophrenic patients. Forty-nine facilities in 2017 were included in the study.

RESULTS

There were dichotomous distributions in the examination rate of TRS and a non-normal distribution in the prescription rate of clozapine. There was a significant correlation between the prescription rate of clozapine and the examination rate of TRS (r_s  = 0.531, P = 1.032 × 10^-4 ). A significant difference was found in the prescription rate of clozapine between the three groups of facilities according to the examination rate of TRS.

CONCLUSION

As a preliminary problem for the use of clozapine, in Japan, the examination rate of TRS varies, and there are many facilities that typically do not consider the possibility of TRS; this trend leads to a low rate of clozapine use. Clearly, further clinician training is needed for the early detection and appropriate management of TRS that includes an explanation of TRS and how to introduce clozapine therapy to patients and their families.

Pharmacological treatment algorithms for the acute phase, agitation, and maintenance phase of first-episode schizophrenia: Japanese Society of Clinical Neuropsychopharmacology treatment algorithms

OBJECTIVE

There are only a few treatment algorithms for first-episode schizophrenia. Moreover, all the algorithms apply to acute treatment, but not maintenance treatment. Therefore, we aimed to develop acute and maintenance treatment algorithms for first-episode schizophrenia.

METHODS

The algorithm committee of the Japanese Society of Clinical Neuropsychopharmacology developed pharmacological treatment algorithms for the acute phase, agitation, and maintenance phase of first-episode schizophrenia.

RESULTS

The acute treatment algorithm focuses on drug-naïve patients with first-episode schizophrenia who are not old or very agitated and recommends first-line treatment with aripiprazole, second- or third-line treatment with risperidone/paliperidone or olanzapine, and fourth-line treatment with clozapine. Long-acting injection of the current antipsychotic agent can be used for poor medication adherence or based on patient preference. The agitation treatment algorithm recommends first-line treatment with lorazepam and second- or third-line treatment with quetiapine or levomepromazine and clearly instructs that the medication used for agitation should be reduced and then discontinued after remission of agitation. The maintenance treatment algorithm recommends the gradual reduction of antipsychotics to the minimum effective dose after remission of positive symptoms.

CONCLUSIONS

We hope that our unique algorithms will be used broadly and will contribute to minimizing patients' burden related to antipsychotic treatment.

Antipsychotic-Related Fatal Poisoning, England and Wales, 1993-2019: The Impact of Second-Generation Antipsychotics

BACKGROUND

Deaths from antipsychotic (AP) poisoning have increased in England and Wales despite restriction of the use of thioridazine in 2000.

METHODS

We analyzed data from the Office for National Statistics drug-related death database, England and Wales, 1993-2019, to investigate fatal AP poisoning.

RESULTS

There were 2286 deaths (62% male patients). Annual numbers of intentional AP-related fatal poisonings (suicides) were relatively stable (1993, 35; 2019, 44; median, 44; range, 30-60). Intentional overdose deaths involving clozapine (96 male, 25 female) increased from 1 in 1994 to 5 in 2003 and have since remained relatively constant (median, 6; range, 3-10 per annum). Unintentional second-generation AP-related fatal poisonings have increased steadily since 1998, featuring in 828 (74%) of all unintentional, AP-related fatal poisonings in the period studied (2019, 89%). There were 181 unintentional clozapine-related deaths, (107 [59%] alone without other drugs ± alcohol) as compared with 291 quetiapine-related deaths (86 [30%] alone without other drugs ± alcohol) and 314 unintentional olanzapine-related deaths (77 [25%] alone without other drugs ± alcohol). Some 75% of all unintentional clozapine- and olanzapine-related deaths were of male patients (78% and 73%, respectively) as compared with 58% of unintentional quetiapine-related fatal poisonings. Clozapine now features prominently in intentional and in unintentional AP-related fatal poisoning in England and Wales. Deaths of male patients predominate in both categories. There were also 77 and 86 deaths attributed to unintentional poisoning with olanzapine and with quetiapine, respectively, in the absence of other drugs.

CONCLUSIONS

More effort is needed to prevent unintentional deaths not only from clozapine but also from olanzapine and quetiapine.

Risk of neutropenia among clozapine users and non-users: results from 5,847 patients

OBJECTIVE

Clozapine is underprescribed due to neutropenia risk. Blood tests every 3 months in those on continuous treatment for > 1 year who have never had an absolute neutrophil count (ANC) < 2,000/µL has been proposed as a monitoring strategy; however, there are no South American data to support this recommendation. This study sought to investigate whether clozapine use and other variables could explain the occurrence of ANC < 1,000/µL in patients with severe mental disorders.

METHODS

A total of 5,847 subjects were included, 1,038 on clozapine. We performed a Cox regression considering the outcome as ANC < 1,000/µL at any time point. Predictors were sex, age, ethnicity, clozapine use, ANC > 2,000/µL during the first year of blood monitoring, and presence of a severe medical condition.

RESULTS

In the Cox regression model, ethnicity (white) (hazard ratio [HR] 0.53; 95%CI 0.29-0.99, p < 0.05) and ANC > 2,000/µL (HR 0.04; 95%CI 0.01-0.10, p < 0.001) were protective factors, while presence of a severe medical condition (HR 69.35; 95%CI 37.45-128.44, p < 0.001) was a risk factor for ANC < 1,000/µL. Other variables were not significant, including clozapine use (HR 1.33; 95%CI 0.74-2.39, p > 0.05).

CONCLUSIONS

These findings suggest that clozapine does not increase the risk of neutropenia in subjects with ANC > 2,000/µL during the first year of use and in the absence of a severe medical condition. These results could help guide clinical and public-health decisions regarding clozapine blood monitoring guidelines.

Cluster Analysis of Clozapine Consumer Perspectives and Comparison to Consumers on Other Antipsychotics

Despite its unique efficacy, clozapine remains underutilized in the United States. Perceptions about clozapine and barriers to its use have been examined among prescribers, but insufficiently studied among consumers. We surveyed 211 antipsychotic consumers (86 on clozapine and 125 on other antipsychotics) on their medication-related perspectives in a public hospital system in Atlanta, Georgia, USA. In contrast to their previous regimen, 72% of clozapine consumers reported they were more satisfied with clozapine. When compared with consumers taking other antipsychotics, clozapine consumers reported more side effects but did not differ on other measures of satisfaction or efficacy. We found Caucasians to be overrepresented among clozapine, as compared to other antipsychotic consumers. Side effects most strongly associated with poor safety ratings were sedation, limb jerking, and dizziness when standing. However, clozapine was only rated less safe by consumers who experienced more than one of these side effects. We used an unsupervised clustering approach to identify three major groups of clozapine consumers. Cluster A (19%) had the lowest safety ratings, aversion to blood work, and a high rate of side effects that associate with lower safety ratings. Cluster B (25%) experienced more hospitalizations and reported satisfaction with clozapine that correlated with efficacy ratings, irrespective of safety ratings. Cluster C (56%) experienced fewer hospitalizations, fewer previous drug trials, greater educational attainment, lower rates of smoking, and rated clozapine more highly. This work identifies common side effects that influence the subjective safety of clozapine and suggests that attitudes toward clozapine depend on context-specific factors.

Patients' and psychiatrists' perspectives on clozapine treatment-a scoping review protocol

INTRODUCTION

The atypical antipsychotic clozapine has shown superior efficacy compared with other antipsychotics and is the gold standard for treating otherwise treatment resistant schizophrenia. However, multiple studies have found that clozapine is underutilised in most parts of the world. A few reviews of literature addressing barriers to clozapine prescribing have been conducted. While there is some variation in the literature included in these reviews, a common feature of the studies included is that they primarily focus on clinical staff's attitudes and perceived barriers for prescribing. Studies of patient perspectives are only sparsely included. A preliminary literature search revealed though, that additional literature on the subject exists, including literature on patient perspectives. It is therefore difficult to conclude if the formerly synthesised literature is representative of current evidence or if the topic has been adequately investigated to inform clinical practice. A scoping review is warranted in order to map and synthesise primary literature on patients' and psychiatrists' perspectives on clozapine treatment, and to identify gaps for future research.

METHODS AND ANALYSIS

The electronic databases Cochrane Library, CINAHL, Web of Science, Psychinfo, MEDLINE and EMBASE will be searched for relevant publications, supplied with searches of Google scholar, The Networked Digital Library of Theses and Dissertations and OpenGrey. Citation tracking of selected studies will furthermore be undertaken. Two researchers will independently screen and extract data. Data will be collated to provide a descriptive summary of the literature, along with a qualitative content analysis of key findings. Identified gaps in research will be accompanied by recommendations for future investigations.

ETHICS AND DISSEMINATION

Findings will be disseminated through a peer-reviewed journal and conference presentations. The scoping review does not require ethics approval.

Environmentally relevant concentrations of clozapine induced lipotoxicity and gut microbiota dysbiosis in Chinese rare minnow (Gobiocypris rarus)

Clozapine (CLZ) is a neuroactive pharmaceutical that is frequently detected in aquatic environments. Although the cardiotoxicity, developmental toxicity, and neurotoxicity of CLZ in aquatic non-target organisms have been reported, its lipotoxicity and underlying mechanism are unknown. Therefore, in this study, 2-month-old Chinese rare minnows were exposed to 0, 0.1, 1, and 10 μg/L CLZ for 90 days. Overt dyslipidemia was observed after CLZ exposure, whereas the body weights of females significantly increased after CLZ exposure (p < 0.05). In addition, obvious hepatocyte vacuolization and hepatic lipid droplet accumulation were observed at all treatment groups (p < 0.05). The activities of sterol regulatory element binding proteins 1 (SREBP1) and fatty acid synthase (FAS) were significantly upregulated at the 1 and 10 μg/L CLZ treatment groups (p < 0.05). Moreover, evident cell boundary disintegration of the intestinal villi and increasing mucus secretion were observed at all treatment groups (p < 0.05). Furthermore, the diversity of the gut microbiota increased, whereas the relative abundances of Proteobacteria, Firmicutes and Bacteroidetes significantly increased after CLZ exposure (p < 0.05). Furthermore, significantly increased bacterial secondary bile acid biosynthesis activity in Chinese rare minnows was observed after 1 μg/L CLZ exposure (p < 0.05). Therefore, our findings confirmed that CLZ induced lipotoxicity by stimulating SREBP1 and affecting the bacterial secondary bile acid biosynthesis activity in Chinese rare minnows.

Antipsychotic treatment strategies for acute phase and treatment resistance in schizophrenia: A systematic review of the guidelines and algorithms

BACKGROUND

To summarize the current state of knowledge on antipsychotic treatment strategies for the acute phase and treatment resistance in schizophrenia, we conducted a systematic review of guidelines and algorithms.

METHODS

We conducted a systematic literature search to identify clinical guidelines and algorithms on this topic using MEDLINE and Embase. We extracted information on recommendations for antipsychotic treatment strategies, including those for non-response (i.e., increasing antipsychotic dose and switching to another antipsychotic) and treatment resistance.

RESULTS

We identified a total of 17 guidelines/algorithms in various countries that were published after 2011. With respect to antipsychotic dose, most of the guidelines (N = 10/11) agreed starting with a low dose or the lowest licensed/effective dose and then titrating the dose upwards. Regarding antipsychotic treatment strategies for non-response, all of the guidelines (N = 9/9) recommended increasing antipsychotic dose towards the upper end of its approved dose range. Five guidelines suggested for increasing beyond the therapeutic dose range in exceptional cases, while overall 10 guidelines including them were negative about such strategy. The vast majority of guidelines (N = 16/17) recommended switching to another antipsychotic for non-response; however, some guidelines mentioned the lack of evidence for these strategies other than the use of clozapine. All the guidelines (N = 17/17) endorsed initiating clozapine after failure to respond to 2 different antipsychotics. Four guidelines endorsed an early use of clozapine, yet as the third antipsychotic.

CONCLUSION

The currently available guidelines and algorithms recommended increasing antipsychotic dose and switching to another antipsychotic, particularly clozapine for treatment-resistant schizophrenia, during the acute phase of schizophrenia for non-response.

New approaches to antipsychotic medication adherence - safety, tolerability and acceptability

INTRODUCTION

Antipsychotic pharmacotherapy is considered a first-line treatment in schizophrenia-related disorders and is associated with favorable prognosis and lower mortality rates. However, low adherence rates present a major clinical challenge. In this paper, we will review contemporary approaches to improve adherence to antipsychotic treatment, considering their mechanism of action, safety, tolerability and acceptability.

AREAS COVERED

Novel pharmacological delivery methods included different routes of administration of registered medications (such as intramuscular clozapine preparation and transdermal asenapine), modifications of existing compounds (such as 3-monthly injectable formulation of paliperidone palmitate), and increased interest in oral long-acting medication formulations (such as with penfluridol). In addition, we reviewed innovative technology to monitor adherence, based on the use of electronic digital medicine systems and ingestible sensors.

EXPERT OPINION

All of these diverse approaches were clinically relevant in enhancing treatment adherence and found to be safe and tolerable. The place of each approach is predicated on a personalized approach in each patient, and future research could usefully use large comparative studies to establish robust treatment guidelines. The implementation of new and varied approaches to antipsychotic treatment adherence is welcomed and have the potential to make a significant impact on morbidity in this often difficult-to-treat population.

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.

Predictors of clozapine discontinuation at 2 years in treatment-resistant schizophrenia

INTRODUCTION

Little is known about predictors of clinical response to clozapine treatment in treatment-resistant psychosis. Most published cohorts are small, providing inconsistent results. We aimed to identify baseline clinical predictors of future clinical response in patients who initiate clozapine treatment, mainly focusing on the effect of age, duration of illness, baseline clinical symptoms and homelessness.

METHODOLOGY

Retrospective cohort of patients with treatment-resistant schizophrenia, aged between 15 and 60 years, that initiated clozapine between 2014 and 2017. Sociodemographic characteristics, years from illness diagnosis, and clinical presentation before the initiation of clozapine were collected and analyzed. All-cause discontinuation at two years follow-up was used as the primary measure of clozapine response.

RESULTS

261 patients were included with a median age at illness diagnosis of 23 years old (IQR 19-29) and a median age at clozapine initiation of 25 (IQR: 21-33). 72.33% (183/253) continued clozapine after two years follow-up. Being homeless was associated to higher clozapine non-adherence, with an OR of 2.78 (95%CI 1.051-7.38) (p = 0.039, controlled by gender). Older age at clozapine initiation and longer delay from first schizophrenia diagnosis to clozapine initiation were also associated with higher clozapine non-adherence, with each year increasing the odds of discontinuation by 1.043 (95%CI 1.02-1.07; p = 0.001) and OR 1.092 (95%CI 1.01-1.18;p = 0.032) respectively.

CONCLUSION

Starting clozapine in younger patients or shortly after schizophrenia diagnosis were associated with better adherence.

Clozapine resistant schizophrenia: Newer avenues of management

About 40%-70% of the patients with treatment-resistant schizophrenia have a poor response to adequate treatment with clozapine. The impact of clozapine-resistant schizophrenia (CRS) is even greater than that of treatment resistance in terms of severe and persistent symptoms, relapses and hospitalizations, poorer quality of life, and healthcare costs. Such serious consequences often compel clinicians to try different augmentation strategies to enhance the inadequate clozapine response in CRS. Unfortunately, a large body of evidence has shown that antipsychotics, antidepressants, mood stabilizers, electroconvulsive therapy, and cognitive-behavioural therapy are mostly ineffective in augmenting clozapine response. When beneficial effects of augmentation have been found, they are usually small and of doubtful clinical significance or based on low-quality evidence. Therefore, newer treatment approaches that go beyond the evidence are needed. The options proposed include developing a clinical consensus about the augmentation strategies that are most likely to be effective and using them sequentially in patients with CRS. Secondly, newer approaches such as augmentation with long-acting antipsychotic injections or multi-component psychosocial interventions could be considered. Lastly, perhaps the most effective way to deal with CRS would be to optimize clozapine treatment, which might prevent clozapine resistance from developing. Personalized dosing, adequate treatment durations, management of side effects and non-adherence, collaboration with patients and caregivers, and addressing clinician barriers to clozapine use are the principal ways of ensuring optimal clozapine treatment. At present, these three options could the best way to manage CRS until research provides more firm directions about the effective options for augmenting clozapine response.

Patterns of antipsychotic prescriptions in patients with schizophrenia in China: A national survey

INTRODUCTION

To investigate the patterns and correlates of antipsychotic prescriptions among recently discharged inpatients with schizophrenia in China.

METHODS

The study included discharged patients from 41 tertiary psychiatric hospitals in 29 provinces between March 19-30, 2019. A total of 1032 inpatients with schizophrenia were included. Socio-demographic and clinical data were retrieved from medical records upon discharge.

RESULTS

Patients received a total of 13 unique antipsychotic medications, which included 9 s-generation antipsychotics (SGAs) and 4 first-generation antipsychotics (FGAs). The utilization rates of SGAs and FGAs were 98.8 % and 6.1 % respectively. The three most commonly antipsychotic medications were risperidone (35.1 %), olanzapine (31.3 %), and clozapine (24.6 %). The mean chlorpromazine equivalent dose was 452.12 ± 230.74 mg/day. The utilization rate of mood stabilizers was 18.9 %, 8.8 % for antidepressants, 20.3 % for sleep improvers, and 9.9 % for anticholinergics. More than two fifths patients (43.1 %) received two or more antipsychotic medications. Predictors of antipsychotic polypharmacy included younger age, residing in Central or West China, a longer duration of illness, a history of prior hospitalizations, and having agitated behavior during the hospitalization.

CONCLUSION

Antipsychotic polypharmacy in China is common on inpatients settings. The proportion of antipsychotic polypharmacy in China is higher than in many other countries, despite limited data to support the efficacy of many combinations. Clozapine remains one of most commonly prescribed antipsychotics in China, either as a monotherapy or combination therapy.

Increased schizophrenia family history burden and reduced premorbid IQ in treatment-resistant schizophrenia: a Swedish National Register and Genomic Study

A high proportion of those with schizophrenia experience treatment non-response, placing them at higher risk for mortality and suicide attempts, compared to treatment responders. The clinical, social, and economic burden of treatment-resistant schizophrenia (TRS) are substantial. Previous genomic and epidemiological studies of TRS were often limited by sample size or lack of comprehensive genomic data. We aimed to systematically understand the clinical, demographic, and genomic correlates of TRS using epidemiological and genetic epidemiological modelling in a Swedish national population sample (n = 24,706) and then in a subgroup with common variant genetic risk scores, rare copy-number variant burden, and rare exonic burden (n = 4936). Population-based analyses identified increasing schizophrenia family history to be significantly associated with TRS (highest quartile of familial burden vs. lowest: adjusted odds ratio (aOR): 1.31, P = 4.8 × 10^-8). In males, a decrease of premorbid IQ of one standard deviation was significantly associated with greater risk of TRS (minimal aOR: 0.94, P = 0.002). In a subset of cases with extensive genomic data, we found no significant association between the genetic risk scores of four psychiatric disorders and two cognitive traits with TRS (schizophrenia genetic risk score: aOR = 1.07, P = 0.067). The association between copy number variant and rare variant burden measures and TRS did not reach the pre-defined statistical significance threshold (all P ≥ 0.005). In conclusion, direct measures of genomic risk were not associated with TRS; however, premorbid IQ in males and schizophrenia family history were significantly correlated with TRS and points to new insights into the architecture of TRS.

Risk mitigation with the use of clozapine - Quo vadimus

The risk of neutropenia decreases significantly after the first year of clozapine initiation, and indefinite hematological monitoring is increasingly questioned. Despite comparable risks of neutropenia, the guidelines for antithyroid drugs - carbimazole and propylthiouracil do not recommend routine hematological monitoring. Assuming a similar pathogenic mechanism, data from antithyroid drugs indicate that neutropenia develops rapidly, and indefinite hematological monitoring misses a large majority of cases in the pre-symptomatic phase. Hence, a more pragmatic strategy of intensive hematological monitoring in the first year of clozapine initiation followed by selective haematological monitoring in case of febrile illnesses or pharyngitis needs to be explored.

Haematologic malignancies associated with clozapine v. all other antipsychotic agents: a pharmacovigilance study in VigiBase®

BACKGROUND

Clozapine is mainly used in patients with treatment-resistant schizophrenia and may lead to potentially severe haematologic adverse events, such as agranulocytosis. Whether clozapine might be associated with haematologic malignancies is unknown. We aimed to assess the association between haematologic malignancies and clozapine using Vigibase®, the WHO pharmacovigilance database.

METHODS

We performed a disproportionality analysis to compute reporting odds-ratio adjusted for age, sex and concurrent reporting of antineoplastic/immunomodulating agents (aROR) for clozapine and structurally related drugs (loxapine, olanzapine and quetiapine) compared with other antipsychotic drugs. Cases were malignant lymphoma and leukaemia reports. Non-cases were all other reports including at least one antipsychotic report.

RESULTS

Of the 140 226 clozapine-associated reports, 493 were malignant lymphoma cases, and 275 were leukaemia cases. Clozapine was significantly associated with malignant lymphoma (aROR 9.14, 95% CI 7.75-10.77) and leukaemia (aROR 3.54, 95% CI 2.97-4.22). Patients suffering from those haematologic malignancies were significantly younger in the clozapine treatment group than patients treated with other medicines (p < 0.001). The median time to onset (available for 212 cases) was 5.1 years (IQR 2.2-9.9) for malignant lymphoma and 2.5 years (IQR 0.6-7.4) for leukaemia. The aROR by quartile of dose of clozapine in patients with haematologic malignancies suggested a dose-dependent association.

CONCLUSIONS

Clozapine was significantly associated with a pharmacovigilance signal of haematologic malignancies. The risk-benefit balance of clozapine should be carefully assessed in patients with risk factors of haematologic malignancies. Clozapine should be used at the lowest effective posology.

Antipsychotic use among persons with schizophrenia in Sweden and Finland, trends and differences

OBJECTIVES

To compare the differences in prevalence of antipsychotic and adjunctive pharmacotherapy use among individuals with schizophrenia between Sweden and Finland during 2006-2016.

METHODS

Nationwide register-based data were utilized for constructing two separate cohorts: all persons in Finland with a diagnosis of schizophrenia treated in inpatient care during 1972-2014, and persons in Sweden aged 16-64 with recorded diagnoses of schizophrenia in inpatient or specialized outpatient care, sickness absence or disability pension during 2005-2013. The prevalence of use was assessed as a point prevalence on 31 October each year 2006-2016, based on drug use periods modelled with the PRE2DUP method. In 2016, the Finnish cohort included 37,780 persons and Swedish cohort 25,433 persons.

RESULTS

The most commonly used antipsychotic in 2016 was oral olanzapine in both countries (22.7% [95% CI 21.6-22.4] in Finland, 20.9% [20.4-21.4] in Sweden), followed by clozapine which was more frequently used in Finland (22.0%, 21.6-22.4) than in Sweden (14.8%, 14.4-15.3). Long-acting injectable (LAI) use was almost two times more likely in Sweden (21.6%, 95% CI 21.1-22.1) than in Finland (12.8%, 12.5-13.1), a difference which was due to more common use of FG-LAIs in Sweden. A four-fold difference was observed in Z-drugs use (19.9% in Sweden versus 5.0% in Finland).

CONCLUSION

Potential explanations for the observed discrepancies include differences in national treatment guidelines, methods of data collection, patient characteristics and/or attitudes towards treatment among both patients and physicians.

Antipsychotic Polypharmacy for the Management of Schizophrenia: Evidence and Recommendations

Schizophrenia is a debilitating illness with a lifetime prevalence estimate of 0.6% and consists of symptoms from the positive, negative, and cognitive domains. Social support, therapy, psychoeducation, and overall case management are very important aspects of the treatment of schizophrenia. However, as abnormalities in neurotransmission are one of the key findings of schizophrenia pathology, pharmacotherapies are cornerstones of the management of schizophrenia. Antipsychotics have been used as the primary pharmacological treatment of schizophrenia. These agents often have a good effect on reducing positive symptoms, but may not markedly improve negative symptoms or cognitive defects. However, at least 20% of individuals with schizophrenia do not experience a substantial response from monotherapy with antipsychotics. Further, despite evolving treatment protocols and advances in early recognition of the disorder, 70% of patients with schizophrenia require long-term, even lifetime, medication to control their symptoms and do not achieve complete recovery. To address these shortcomings, clinicians and research scientists have explored different combinations of treatments, polypharmacy, to improve the treatment of patients. Antipsychotic polypharmacy has been shown to cause more side effects than monotherapy, which is the main reason why most treatment guidelines caution against it. Antipsychotic monotherapy should be strived for and clozapine should be tried at the latest if two monotherapy trials with other antipsychotics have failed and no absolute contraindications exist. If residual symptoms exist despite trials of adequate dose and duration, other reasons that may reduce treatment effect should be ruled out. Long-acting injectables or blood concentration measurements should be considered to affirm compliance and proper serum levels. Antipsychotic polypharmacy should be considered and discussed with patients from whom the aforementioned procedures do not produce a satisfactory treatment result. In some cases, antipsychotic polypharmacy may produce better results than other forms of treatment augmentation, such as benzodiazepines. In particular, combining aripiprazole with clozapine may be effective in reducing treatment side effects or residual symptoms, and this is likely to hold true for combining other partial dopamine D₂ agonists with clozapine as well, although currently scant data exist. More research is needed, both in controlled but also real-world settings, to define optimal antipsychotic polypharmacy and/or other psychotropic treatment augmentation strategies for specific patient groups and situations.