Morning pseudoneutropenia during clozapine treatment

World J Biol Psychiatry. 2003 Oct;4(4):192-4. doi: 10.1080/15622970310029918.


Clozapine, an atypical antipsychotic drug, is associated with a high risk of neutropenia and agranulocytosis, necessitating the immediate discontinuation of the drug. We report the case of a patient who developed clozapine-induced neutropenia. Assessments revealed a pronounced diurnal variation in the number of circulating neutrophils (1200-1900/mm(3) in the morning and 2200-2700/mm(3) in the afternoon). Due to these circadian changes, we decided to continue clozapine treatment.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Antipsychotic Agents / adverse effects*
  • Antipsychotic Agents / therapeutic use
  • Circadian Rhythm*
  • Clozapine / adverse effects*
  • Clozapine / therapeutic use
  • Humans
  • Male
  • Neutropenia / chemically induced*
  • Neutropenia / diagnosis
  • Schizophrenia, Paranoid / blood
  • Schizophrenia, Paranoid / drug therapy*


  • Antipsychotic Agents
  • Clozapine