The disquietude of clozapine continuation during the COVID‐19 pandemic

Clozapine research from India: A systematic review

BACKGROUND

Although clozapine is much researched in western literature, a review on Indian research on clozapine published in 2010 reported limited data and need for further research in this area.

AIM

We aimed to conduct a systematic review of research on clozapine from India from 2010 to mid-2022 and also compare the same with research output before 2010.

METHODOLOGY

A systematic various search engines, i.e., PUBMED, Medknow, Hinari and Google Scholar was done using the key words clozapine and India. Published articles with clozapine in the title and having an author from India, published during 2010 to July 2022 were included.

RESULTS

Initial Internet and hand searches yielded 280 articles, out of which 126 articles were excluded due to various reasons and 154 articles, were included for the review. This included 84 case reports, 49 original articles, 11 review articles and 10 letters to the editor as comments. We found an increase in the number of publications during the period of 2010-2022 compared to 1997-2009 in all types of publications. Over the years a significant proportion of the articles focused on various side effects of clozapine, factors associated with response and non-response to clozapine and evaluation of outcomes other than efficacy/effectiveness. However, all the studies were limited to a single centre with no multicentric studies on clozapine.

CONCLUSION

Over the last 12 years or so, there is increase in the number of publications on clozapine. However, there is lack of multicentric studies.

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.