Clozapine, neutropenia and Covid-19: should clinicians be concerned? 3 months report

Bonaccorso, Stefania; Ricciardi, Angelo; Ouabbou, Sophie; Theleritis, Christos; Ross-Michealides, Arabella; Metastasio, Antonio; Stewart, Neil; Mohammed, Marwa; Schifano, Fabrizio

BACKGROUND: Clozapine is among the most effective antipsychotic used for treatment resistant schizophrenia. Adverse reactions to clozapine include neutropenia. In March 2020, at the start of the Coronavirus -19 pandemic, clinicians raised concerns regarding continuation of antipsychotic treatment, and specifically of clozapine, in patients with coronavirus disease. We aimed here at providing a short report focusing on the association between neutropenia and clozapine in a case series of psychiatric inpatients diagnosed with COVID-19. PATIENTS & METHODS: We retrospectively inspected data of 10 patients on clozapine, admitted to Highgate Mental Health Centre -Camden & Islington NHS Foundation Trust between March and July 2020; selection was based on their COVID-19 positive PCR test. We used a linear regression model to estimate whether there was a significant drop in the neutrophil count during SARS-CoV-2 infection. The analysis was done in R using a linear regression to the origin. RESULTS: Data were collected on 10 patients, of which 7 were males. During COVID-19 infection, neutrophils’ count (ANC) 4.13 × 109/l (SD = 2.70) from a baseline value of 5.2 × 109/l (SD = 2.24). The mean relative reduction in ANC was -0.2729 (SD = 0.1666). The beta value of 0.8377 obtained with the linear regression showed that ANC values during SARS-CoV-2 infection were 83.77% of the baseline ANC showing that within the two time points there was a decrease in ANC of 16.23%. The linear regression had a pvalue = 8.96 x 10-8 and an adjusted R2 of 95.94% which shows that the variability of the data is very well explained by the model. We also compared baseline ANC with ANC values approximately a month after resolution of the infection and results indicate that ANC values return to a 95% of baseline. CONCLUSIONS: Clinicians should bear in mind that a significant drop in neutrophils’ count may occur in patients taking clozapine and affected from a SARS-CoV-2 infection and that this drop is only transitory