Continuation with clozapine after eosinophilia: a case report

Area of Science:

• Psychiatry
• Hematology
• Pharmacology

Background:

• Clozapine is an atypical antipsychotic used for treatment-resistant schizophrenia.
• Clozapine-induced eosinophilia is a reported, though uncommon, blood dyscrasia.
• The incidence of clozapine-induced eosinophilia varies geographically, with higher rates of associated myocarditis in Australia.

Observation:

• A 54-year-old male with treatment-resistant schizophrenia developed eosinophilia after initiating clozapine therapy.
• The patient showed significant improvement in psychotic symptoms with clozapine.
• Medical workup revealed no signs of end-organ inflammation despite elevated eosinophil counts.

Findings:

• Eosinophil counts normalized spontaneously within three weeks while clozapine treatment continued.
• The patient tolerated dose escalation of clozapine up to 400 mg/day without recurrence of eosinophilia or organ inflammation.
• This case suggests clozapine-induced eosinophilia may represent an acute allergic reaction.

Implications:

• Continuation of clozapine may be feasible in cases of eosinophilia without end-organ inflammation, under close hematological monitoring.
• This approach can help maintain essential antipsychotic treatment for patients with schizophrenia.
• Further research into the pathophysiology of clozapine-induced eosinophilia is warranted.