Agranulocytosis during clozapine therapy.

Granulocytopenia and agranulocytosis are considered among the most dangerous adverse effects of clozapine. During the last 15-year period, this atypical antipsychotic agent has been administered to 750 patients managed at the Emergency Psychiatry Services and Clinical Pharmacology Unit of the National Institute of Psychiatry and Neurology (NIPandN; Budapest, Hungary). Granulocytopenia was ascertained in seven, whereas agranulocytosis was diagnosed in two patients of this population. The latter two comprised a 42-year-old female with schizoaffective psychosis and a 35-year-old male with paranoid schizophrenia. The female patient received clozapine in a daily dose of 400 mg, which induced agranulocytosis after 2 months. The male patient was treated with 225-mg/day clozapine and the time to the diagnosis of agranulocytosis was 6 weeks. These adverse reactions were recognized early and the appropriate treatment of agranulocytosis resulted in complete recovery in both cases.