[Clozapine and agranulocitosis in Spain: do we have a safer population? A 5-year hematologic follow-up]

Abstract

Introduction: Clozapine is an efective antipsychotic. However, its use has been associated with agranulocitosis. For this reason, it has been restricted for the treatment of resistant schizophrenia under a strict hematologic control. The objective of this work was to assess the risk of hematologic dyscrasias in a sample of clozapine-treated patients in a 5-year period.

Materials and method: This is a follow-up study in a cohort of clozapine-treated patients in which the risk of haematological dyscrasias was assessed. Complete blood cell count was made for each patient in a weekly basis for the first 18 weeks and thereafter monthly.

Results: 271 patients in treatment with clozapine were followed up. The mean age was 32.3 years, with 36.5% women. The mean dose was 227,6 mg, ranging from 25 to 600 mg/day. During the first 18 weeks of follow-up, we observed a 3% incidence of neutropenia and 1.3% of leucopenia. During the next two years, only one new case of neutropenia and leucopenia was observed (n=120). No new cases were observed during the rest of follow up (n=69). No cases of agranulocytosis were observed.

Conclusions: A 3% incidence of neutropenia concentrated in the first months of follow up and no cases of agranulocitosis were observed in our sample. Actual evidence on clozapine effectiveness and safety and the results of this study suggests that a critical revision of follow-up protocols is suitable.