Clozapine, neutropenia and Covid-19: should clinicians be concerned? 3 months report
Stefania Bonaccorso, A Ricciardi, Sophie Ouabbou, Christos Theleritis, Arabella Ross-Michaelides, Antonio Metastasio, Neil Stewart, Marwa Mohammed, Fabrizio Schifano
Abstract
Clozapine is among the most effective antipsychotics 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. 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. Data were collected on 10 patients, of which 7 were males. During COVID-19 infection, neutrophils’ count (ANC) was 4.13 × 109/l (SD = 2.70) which constituted a significant drop 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 of 16.23%. The linear regression had a pvalue = 8.96 × 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. 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 infectionand that this drop is only transitory.