Background: The clozapine-derivative quetiapine has been shown in some cases to cause
leukopenia and neutropenia.
Case Presentation: We reported on a case of a young female diagnosed with treatment-resistant
schizophrenia. After failed trials of three antipsychotic medications and despite a history of quetiapineinduced
leukopenia, clozapine treatment was introduced due to the severity of the patient’s symptoms,
the limited effective treatment options, and a lack of guidelines on this issue.
Result: Over a ten-week period of clozapine treatment at 700 mg per day, the patient developed
agranulocytosis. Her white blood cell count sharply dropped to 1.6 × 109 L, and her neutrophils
decreased to 0.1 × 109 L. There had been no similar reaction to her previous medications
(carbamazepine, risperidone, and haloperidol).
Conclusion: The safety of clozapine in a patient who has previously experienced leukopenia and
neutropenia with quetiapine requires further investigation. Increased attention should be paid to such
cases. Careful monitoring and slow titration are advisable.