Clozapine and Neutropenia in Patients with Schizophrenia and SARS-CoV-2 Infection

Change in absolute neutrophil count after COVID-19 infection in patients using clozapine versus other antipsychotics

It was reported that patients who contracted COVID-19 while taking clozapine exhibited a distinct hematological response. However, the absence of control groups made it difficult to attribute it to clozapine. The changes in absolute neutrophil counts (ANCs) during the 4 weeks after COVID-19 infection were compared between the two groups of patients with severe mental illnesses (SMIs) (49 patients using clozapine and 54 using other antipsychotics) using generalized additive modeling. Although the pattern of a transient drop in ANC followed by gradual recovery could be demonstrated in both groups, it was more pronounced in the clozapine group ( P  = 0.00025). Nevertheless, overall ANC remained at a higher level in the clozapine group. The results suggested potential interaction between clozapine and COVID-19 at the level of hematological dynamics. However, it did not necessarily indicate that such interaction is inevitably harmful or dangerous. It was more of a concern that some patients using other antipsychotics exhibited decreased ANC, which did not easily recover. Traditionally, clinicians have been concerned about the worsening of hematological side effects in clozapine patients after COVID-19 infection. However, the obtained result highlighted the necessity of hematological monitoring in patients using any type of antipsychotics for SMIs.

Can lithium be used in the setting of clozapine commencement in patients with COVID-19 associated neutropenia: A case report

COVID-19 infection may increase the likelihood of neutropenia in patients already on clozapine. In clozapine treated patients experiencing COVID-19 associated neutropenia, adjunct therapy with lithium can be considered.

Association between initial clozapine titration and pneumonia risk among patients with schizophrenia in a Korean tertiary hospital

Pneumonia is a significant adverse drug reaction (ADR) associated with clozapine, characterized by high mortality and potential linkage with other inflammatory responses. Despite the critical nature, research regarding the development of pneumonia during initial clozapine titration remains limited. This retrospective study included 1408 Korean inpatients with schizophrenia spectrum disorders. Data were collected from January 2000 to January 2023. Pneumonia developed in 3.5 % of patients within 8 weeks of clozapine initiation. Patients who developed pneumonia were taking a greater number and higher dose of antipsychotics at baseline (2.14 vs. 1.58, p < 0.001; 25.64 vs. 19.34, p = 0.012). The average onset occurred 17.24 days after initiation, on an average dose of 151.28 mg/day. Titration was either paused or slowed in most of these patients, with no reported fatalities. The types of pneumonia included aspiration pneumonia, mycoplasma pneumonia, bronchopneumonia, and COVID-19 pneumonia. Myocarditis, drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, and urinary tract infections were also identified. Logistic regression analysis revealed that a greater number of concomitant antipsychotics (odds ratio [OR] = 1.59, p = 0.027) and concomitant benzodiazepine use (OR = 2.33, p = 0.005) at baseline were associated with an increased risk of pneumonia. Overall, pneumonia development during clozapine titration is linked with other inflammatory ADRs, suggesting a shared immunological mechanism. Close monitoring is recommended, especially for patients taking multiple antipsychotics and benzodiazepines. Further studies involving repeated measures of clozapine concentrations at trough and steady state, along with a more detailed description of pneumonia types, are warranted.

Schizophrenia and the COVID-19 pandemic: A narrative review from the biomedical perspective

The outbreak of the Coronavirus Disease 2019 (COVID-19) pandemic in 2020 caused a rapid worsening of global mental health. Patients with severe mental disorders, including schizophrenia, are at higher risk of being infected. The neuroinvasive potential of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) has been confirmed. The aim of this article was to present a narrative and comprehensive review of multidimensional associations between schizophrenia and COVID-19 with special emphasis on common biological pathways. Online searches were performed in the PubMed database and covered the publication period until September 17, 2022. Search terms included "psychosis", "schizophrenia", "inflammation" and "COVID-19". Viewed as a neuroinflammatory state, schizophrenia shares several neurobiological mechanisms with the COVID-19. Environmental stress, common comorbidities of schizophrenia and adverse effects of antipsychotic treatment are associated with the higher severity and mortality of the COVID-19. Additionally, more frequent relapses of psychosis have been observed, and might be related to lower treatment adherence. In the context of clinical manifestation, higher level of negative symptoms has been identified among patients with schizophrenia during the pandemic. Improvements in mental health care policy and treatment adjustment are necessary to protect people with schizophrenia who are the population that is particularly vulnerable to the consequences of the COVID-19 pandemic. Future research will show if prenatal infection with the SARS-CoV-2 increases a risk of psychosis.

Outcome of COVID-19 mRNA Vaccination in Patients Treated With Clozapine WHO Previously Went Through SARS-COV-2 Infection

BACKGROUND

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic had multiple consequences for the health care system, especially for patients with mental illnesses. Schizophrenia patients particularly appear to have a higher risk of complications due to coronavirus-19 (COVID-19). Clozapine remains the gold standard for treatment-resistant schizophrenia (TRS). However, the COVID-19 pandemic had an important negative impact on clozapine treatment, mainly because of its administration protocol, which was very difficult to follow during the restrictions imposed in the pandemic, and its side effects in patients with COVID-19 infection. Vaccination is an effective method of avoiding SARS-CoV-2 infection or its severe complications, especially in susceptible populations. Data on adverse events after vaccination against COVID-19 are limited, both in the general population and in schizophrenia patients.

STUDY QUESTION

The study aimed to investigate the safety of COVID-19 vaccination in patients treated with clozapine for hematological parameters.

STUDY DESIGN

We conducted an analytical cross-sectional study between July 1, 2021, and June 30, 2022. We compared 2 groups of COVID-19 vaccinated patients who had previously experienced SARS-CoV-2 infection: The first group was treated with clozapine, whereas the second group was treated with other antipsychotics.

MEASURES AND OUTCOMES

The primary objective was to identify granulocytopenia, leukocytopenia, and lymphocytopenia. The results were measured after the second dose of the Pfizer-BioNTech vaccine.

RESULTS

This study included 100 patients. White blood cell count changes were limited to a few cases of mild granulocytopenia (8.16% in the clozapine group and 3.92% in the nonclozapine group, P = 0.37) with no cases of severe granulocytopenia or agranulocytosis.

CONCLUSIONS

As far as leukocyte counts are concerned, mRNA COVID-19 vaccination seems to be safe in patients treated with clozapine who previously had SARS-CoV-2 infection. Leukocyte changes had no clinical implications.

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 Therapy and COVID-19: A Systematic Review of the Prevalence Rates, Health Outcomes, Hematological Markers, and Patient Perspectives

BACKGROUND/OBJECTIVES

There have been concerns that clozapine treatment may undermine the capacity of the body to fight infection and increase the vulnerability to contracting COVID-19. This review of recent cohort studies investigated (1) whether people with a severe psychiatric disorder are at increased risk of COVID-19 and complications, (2) the immunological response of clozapine-users who contract COVID-19, and (3) patients' perspectives on COVID-19 and the pandemic response.

METHODS

A systematic search of EMBASE, Medline, Pubmed, and PsycINFO databases using PRISMA guidelines using "COVID-19", "clozapine", and "vaccination" terms.

RESULTS

18 studies (out of 330 identified) met all criteria (N = 119 054 including 8045 on clozapine). There was no strong evidence that clozapine users may be at increased risk of contracting COVID-19 or developing complications after adjusting for medical comorbidities. Hematological studies showed temporary reductions in neutrophils in COVID-19-positive patients and vaccination suggesting a clozapine effect in defence against infection. Vaccination studies did not report major adverse effects. Increased plasma levels of clozapine and neutropenia however point to COVID-19-related interference of clozapine metabolism. Patient surveys reported limited impact on mental health and positive attitudes regarding pandemic response.

CONCLUSION

This review did not find compelling evidence that the immune system of clozapine users put them at risk of COVID-19 and further complications. Evidence of drug-infection interactions however points to the importance of adhering to consensus guidelines about clozapine therapy during the pandemic. More evidence using longitudinal designs is required to examine the longer-term effects of COVID-19 and vaccination in this vulnerable population.

Long-Acting Injectable Antipsychotics (LAIs) Prescribing Trends during the COVID-19 Pandemic in Romania

Long acting injectable antipsychotics (LAIs) are considered the ideal treatment for schizophrenia, especially for young patients with high rates of non-adherence. In the current COVID-19 pandemic, it has been reported that the administration of LAIs decreased in some areas. The aim of this study was to evaluate the impact of COVID-19 pandemic on the initiation of LAIs. This is a retrospective mirror- image study covering a total period of 24 months: 12 months before and 12 months after the declaration of COVID-19 pandemic on March 11, 2020. During the study period, out of 218 patients admitted with schizophrenia, only 15 (1.3%) received LAIs at discharge. There was a 48.3% reduction in LAIs initiation compared to the pre-pandemic period (29 LAIs initiations in 2019 from 224 admissions). Despite the 27% reduction in the total number of admissions (1500 in 2019 vs. 1100 in 2020), the number of admissions with schizophrenia remained almost the same (224 in 2019 vs. 218 in 2020). COVID-19 pandemic brought an important challenge in the treatment of patients with schizophrenia, especially in the initiation of LAIs. This could have an important impact on the relapse rate in the next period.

Neutropenia in Patients With Clozapine-Treated Schizophrenia: An Effect of Clozapine or a Consequence of SARS-CoV-2 Infection? A Systematic Review

BACKGROUND

Clozapine is the only approved antipsychotic for treatment-resistant schizophrenia. Despite its therapeutic benefits, it is still widely underused, mainly because of its potential to cause agranulocytosis and neutropenia. Prescribing clozapine in COVID-19-positive patients became more challenging because of this potential side effect. This article is a review of literature on the risk of neutropenia associated with clozapine treatment in patients with COVID-19.

AREAS OF UNCERTAINTY

In clozapine-treated COVID-19-positive patients, neutropenia was reported in some cases; is it a consequence of clozapine treatment or of SARS-Co2 infection?

DATA SOURCES

Data were extracted from 2 databases: PubMed/MEDLINE and Google Scholar. We selected all original reports, from March 2020 until May 2022, on neutropenia associated with clozapine treatment in positive COVID-19 patients. Eleven studies were selected for the final analysis.

THERAPEUTIC ADVANCES

Before the COVID-19 pandemic, neutropenia in clozapine-treated patients was reported in 3.8% of cases. During the pandemic, neutropenia rates seemed to be higher. As per the cause of neutropenia, studies reported contradictory results. We aim to clarify rates and causes of neutropenia in clozapine-treated COVID-19-positive patients.

RESULTS

Three hundred eighty-eight articles were initially selected from the 2 databases. After excluding duplicates, unrelated articles, reviews, and guidelines, 11 studies were analyzed, all centered on clozapine treatment, COVID-19 infection, and associated neutropenia.

CONCLUSIONS

Clozapine treatment in COVID-19-positive patients may be associated with a transient reduction of absolute neutrophils count, in some cases reaching neutropenia levels. Neutropenia rates reported in SARS-CoV-2-infected patients are higher than the prepandemic reports; therefore, we assume that the cause might be a result of the immunological interference between clozapine and SARS-CoV-2. Clozapine treatment needs to be continued whenever possible, with dose adjustments in relation to blood test results.