Clozapine is the only available treatment for
refractory schizophrenia but its use involves frequent physical contact with healthcare workers for the purpose of mandatory blood monitoring. During the
COVID-19 pandemic, patients taking
clozapine will be self-isolating to reduce the risk of
infection, not least because these patients are at high risk of serious illness and fatality because of high rates of diabetes,
obesity and
pulmonary disease and an increased risk of
pneumonia. Problems may also arise because both
clozapine-induced
myocarditis and neutropenic
sepsis share signs and symptoms with
COVID-19 (
fever,
chest pain, dyspnoea, etc.). We recommend decreasing the frequency of physical contacts by extending the blood monitoring interval to 12 weeks in those patients taking
clozapine for more than 1 year. To distinguish
COVID-19 from
clozapine-related physical adverse effects, we suggest an urgent
antigen test alongside a full blood count. In those taking
clozapine who develop
COVID-19, we suggest continuing with
clozapine whenever possible (even during ventilation), reducing the dose if necessary in line with blood assay results. Blood monitoring should continue but
clozapine should only cease if there is a significant fall in neutrophils (
COVID-19 is linked to
lymphopenia but not
neutropenia). To protect against the likelihood and severity of respiratory
infection, we recommend the use of
vitamin D in all
clozapine patients. Initiation of
clozapine is likely to remain problematic while the risk of
infection remains, given the degree of physical contact required to assure safety.