Clozapine-associated agranulocytosis: risk and aetiology.

This paper reviews the epidemiology and pathogenesis of clozapine-associated agranulocytosis. According to present clinical experience, granulocytopenia can be expected in approximately 3% of patients during clozapine treatment. The risk of serious sequelae of granulocytopenia can be minimised by regular white blood cell count monitoring. Although research suggests that some patient groups may be at higher risk of developing this serious adverse reaction, we cannot yet predict the susceptible patients, so all patients exposed to clozapine should receive regular blood monitoring throughout treatment. Because of the risk of agranulocytosis, clozapine should only be used in schizophrenic patients who are resistant to, or intolerant of, conventional antipsychotic medications. Unless compliance with blood monitoring is assured, clozapine treatment should not be recommended.