Clozapine Induced Neutropenia In Patients Suffering From Schizophrenia: A Multi Centre Audit

Abstract

Objective: To determine the frequency of clozapine induced neutropenia and its associated clinical features
among the patients suffering from schizophrenia.
Design: Cross sectional, comparative
Place and duration of study: The study is based on the blood count reports from various centres in
Pakistan using Clozapine during a period 1992-2005.
Subjects and Methods: The medical records of 917 patients with a diagnosis of schizophrenia, aged 18
years and above were reviewed. Patient’s profile was evaluated consisting of gender, dose of clozapine,
duration of treatment and complete blood count (CBC) findings including white blood cell (WBC) count
or absolute neutrophil count (ANC), before starting the treatment. The case records showing WBC count
below 3000 and ANC count less than 500 were identified and details of the clinical and sociodemographic
variables were recorded on a proforma.
Results: Thirty eight patients (4.1%) developed clozapine induced neutropenia. Median duration of
clozapine treatment in these patients was 6.0 years that was significantly higher than Median = 1 year of
those patients who did not develope neutropenia (p < 0.001). An inverse correlation (r = -0.046) was
observed between ANC and duration of clozapine induction. Median dose (mg) of clozapine induced
neutropenia patients was higher (200 vs. 150, p = 0.262), however statistically insignificant.
Conclusion: The incidence of clozapine induced neutropenia of our study is comparable with that of
worldwide reported incidence. Prolongation of treatment also increase the incidence.
Key words: Schizophrenia, Clozapine, Neutropenia.