The Effect of Clozapine on Hematological Indices: A 1-Year Follow-Up Study.
Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and is linked to a need for mandatory hematological monitoring. Besides agranulocytosis, other hematological aberrations have resulted in premature termination in some cases. Considering clozapine's role in immunomodulation, we proceeded to investigate the impact of clozapine on the following 3 main hematological cell lines: red blood cells, platelets, white blood cells (WBCs), and its differential counts. Data were extracted from patients initiated on clozapine between January 2009 and December 2010 at a single hospital. Patients with a preclozapine complete blood count, who were receiving clozapine during the 1-year follow-up period, were included in the present investigation. Counts of red blood cells, platelets, WBC, and its differential including neutrophils, lymphocytes, monocytes, eosinophils, and basophils were extracted and trajectories plotted. One hundred one patients were included in this study and 66 remained on clozapine at the end of 1 year. There was a synchronized but transient increase in WBC, neutrophils, monocytes, eosinophils, basophils, and platelets beginning as early as the first week of clozapine treatment. There were no cases of agranulocytosis reported in this sample, and five developed neutropenia. A spike in neutrophils immediately preceded the onset of neutropenia in three of the five. The cumulative incidence rates were 48.9% for neutrophilia, 5.9% for eosinophilia, and 3% each for thrombocytosis and thrombocytopenia. Early hematological aberrations are visible across a range of cell lines, primarily of the myeloid lineage. These disturbances are transient and are probably related to clozapine's immunomodulatory properties. We do not suggest discontinuing clozapine as a consequence of the observed aberrations.
From the *Department of General Psychiatry 1, Institute of Mental Health; †Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore; ‡Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; §Department of Neuropsychiatry, Keio University, School of Medicine, Tokyo, Japan; ∥Institute of Medical Science, University of Toronto; ¶Geriatric Mental Health Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; #Division of Clinical Pharmacology, Indiana University School of Medicine; **Indiana Clinical and Translational Sciences Institute, Indianapolis, IN; ††Campbell Family Mental Health Research Institute; and ‡‡Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
Jimmy
J
Lee
Hiroyoshi
H
Takeuchi
Gagan
G
Fervaha
Valerie
V
Powell
Amaal
A
Bhaloo
Robert
R
Bies
Gary
G
Remington
D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001772:Blood Cell Count; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006402:Hematologic Diseases / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy*; D055815:Young Adult
D014150:Antipsychotic Agents; D003024:Clozapine