NEUTROPENIA AND AGRANULOCYTOSIS IN PATIENTS RECEIVING CLOZAPINE IN THE UK AND IRELAND

Background. Clozapine can cause reversible agranulocytosis and neutrop enia. This study documents the occurrence of blood dyscrasias and iden tifies predisposing risk factors. Method. An analysis was made of the haematological, demographic, and dosage data from a central database o n 6316 patients receiving clozapine over four and a half years in the UK and Ireland. Results. During the study period, 2.9% of the patients developed neutropenia and 0.8% developed agranulocytosis. The peak in cidence of both disorders was in the first 6-18 weeks of treatment. Fa tal agranulocytosis occurred in 0.03% of patients. After the first yea r of treatment, the incidence of agranulocytosis significantly decreas ed to the order noted with some phenothiazines. Conclusions. The use o f a patient monitoring service kept the haematological risks associate d with using clozapine within acceptable limits, particularly in view of the benefits of this medication in treatment-resistant schizophreni a.