Korean J Psychopharmacol.  1999 Oct;10(2):166-172.

Agranulocytosis and Neutropenia in Clozapine-Treated Patients

• Cho HS
• An SK
• Kim CH
• Lee HS

Abstract

OBJECTIVE
Clozapine is effective in the treatment of refractory schizophrenic patients, but can cause reversible and fatal food dyscrasias. This study documents the incidence of agranulocytosis and neutropenia and the characteristics of patients with clozapine-inducted agranulocytosis. METHOD: An analysis was made of the hematological, demographic, and other characteristics data from Clozaril Patient Monitoring System(CPMS) data on 2139 patients on clozapine over about 3 years in Korea.
RESULTS
During the study period, agranulocytosis developed in 11 patients and 9 (81.8%) patients occurred within 18 weeks. The cumulative incidence of this side effect was 0.57% at 6 months and 0.65% at 1 to 3 years and the crude incidence was 0.51%. Neutropenia occurred in 157 patients and 114(72.6%) ones developed within 18 weeks. The crude incidence of this blood abnormality was 6.9% at 1 year and 7.3% at 3 years. The cumulative incidence was 9.0% at 1 year and 28.7% at 3 years. The hazard rates far agranulocytosis and neutropenia peaked during the 3rd month and 2nd month, respectively.
CONCLUSIONS
These results showed that the incidence of agranulocytosis in Korea may be lower than in USA and UK, at least during the early years of clozapine marketing. Also those suggest that the CPMS in Korea serves as a effective early warning system to promote the safety and benefits of clozapine.

Keyword

Agranulocytosis; Neutropenia; Clozapine

MeSH Terms

Agranulocytosis*
Clozapine
Humans
Incidence
Korea
Marketing
Monitoring, Physiologic
Neutropenia*
Clozapine