한국에서 11년간 Clozapine 투여에 의한 무과립구증과 호중구감소증

Objectives : Clozapine is effective in treating patients with treatment-resistant schizophrenia. Because of producing a potentially fatal agranulocytosis, the use of clozapine is restricted to patients who are resistant to, or intolerant of, conventional antipsychotic medication. This study documents the incidence of agranulocytosis and neutropenia, and pattern of variation in incidence of these side effects in a long-term clozapine treatment. Methods : An analysis was made of the hematological, demographic, and other characteristics data from Clozaril Patient Monitoring System(CPMS) data on 6782 patients on clozapine over about 11 years in South Korea. Results : During the study period, agranulocytosis developed in 54 patients with 29(53.7%) cases within 18 weeks. The cumulative incidence of agranulocytosis was 1.64% at 6 to 11 years and the crude incidence was 0.8%, with the hazard rates peaking at the 3rd month(0.0025) and 2nd month(0.0014). Neutropenia occurred in 697 patients, and 365(52.4%) cases developed within 18 weeks. The cumulative incidence of this blood abnormality was 19.8% at 8 to 11 years, the crude incidence was 10.3%, and the hazard rates peaked at the 2nd month(0.0188). Conclusions : These results showed that the incidence of agranulocytosis in South Korea is similar to that in the rest of the world. Because of agranulocytosis that occurred after several years of clozapine use, long-term monitoring of patients' white blood cell counts is necessary. In the future, studies of reducing the frequency of hematologic monitoring are needed, and the concept of "transient agranulocytosis' should be taken into consideration.