A case report: Clozapine‐induced leukopenia and neutropenia after mRNA COVID‐19 vaccination

Abstract

Abstract Clozapine is an atypical antipsychotic used for treatment‐resistant schizophrenia and is known to cause serious side effects, such as leukopenia and neutropenia. We encountered the case of a 44‐year‐old female patient with a good response to clozapine, who experienced inflammatory reaction and cytopenia after coronavirus disease 2019 (COVID‐19) vaccination. Soon after clozapine discontinuation, the inflammatory reaction resolved, and cell counts recovered. There are only a few reports on the interaction between clozapine and COVID‐19 vaccine. Our findings suggest that caution is required when a patient who is receiving clozapine scheduled for COVID‐19 vaccination, owing to the possibility of cytopenia. Moreover, blood tests and the measurement of clozapine concentration should be performed before and after the inoculation to ensure patient safety.

Keywords

• clozapine
• COVID‐19 vaccine
• leukopenia
• neutropenia
• schizophrenia