Incidence of leukopenia and agranulocytosis in 239 Thai patients treated with clozapine
Pichet Udomratn, Assoc. Prof. D. of Psychiatry, F. of Medicine, PSU.
E-mail : upichet@ratree.psu.ac.th
Published : J Psychiatr Assoc Thailand 2000, 45(3) : 229-236
Key words : clozapine, neutropenia, agranulocytosis, WBC monitoring, Thai patients
Objectives : Clozapine was re-introduced again in Thailand on March 24, 1995 with WBC monitoring but there was no report concerning this issue. Therefore, the objectives of this study are: (1) to find out the incidence of clozapine induced neutropenia or agranulocytosis on Thai patients,
(2) to compare results with other countries, and (3) to examine the currently monitoring system and propose a better national registry.
Method : WBC records of 239 Thai patients receiving clozapine between January 1, 1997 and September 30, 1998 were collected and analysed. The US definitions of mild, moderate, and severe leukopenia were used. Rates of leukopenia, agranulocytosis, and fatalities were reported in number
and percentage.
Results : No neutropenia or agranulocytosis was found. Only 1.4% of clozapine treated
patients at the 6-12 month period and 2.4% at the 12-18 month period had WBC in the range of
3500-4000/mm3.
Conclusions : Although our data did not show the risk of developing clozapine induced leukopenia or agranulocytosis, it does not mean that we do not have such problems. The author recommends development of a centralized nationwide and to serve as a tool for quality assurance.
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