Clozapine‐Associated Neutropenia With COVID‐19 Infection and the Role of Filgrastim

ABSTRACT Clozapine is the gold standard, evidence‐based treatment of choice for treatment‐resistant schizophrenia. However, clozapine can induce serious, life‐threatening adverse effects, including neutropenia and agranulocytosis. There is accumulating evidence to suggest that rechallenging with clozapine should be considered in most patients with clozapine‐associated neutropenia (mild to moderate neutropenia) who do not respond to other treatments. Ruling out other causes of coincidental neutropenia is important when the neutropenia occurs after 2 years of treatment on clozapine, as the risk of developing neutropenia becomes negligible after 2 years and becomes nonspecific to clozapine. When our patient developed neutropenia whilst taking clozapine during Covid‐19 infection, she benefitted from Filgrastim [a Granulocyte‐Colony Stimulating Factor (G‐CSF)], which provided symptomatic treatment.