Agranulocytosis after long-term clozapine use: a case report

Neutropenia and the more severe, potentially life-threatening agranulocytosis are recognized side effects of clozapine that require regular, mandatory, and life-long blood monitoring. However, most cases of haematological adverse effects occur in the first few months of treatment; therefore, there are now increasing calls for the termination of the mandatory monitoring after this initial period. In this report, we present a patient with treatment-resistant schizophrenia who was successfully treated with clozapine yet developed neutropenia after 9 years. This soon evolved into agranulocytosis requiring the use of granulocyte colony-stimulating factor and eventual clozapine cessation. Such late-onset cases of agranulocytosis are isolated and rare but should not impede the drive to relax mandatory clozapine haematological monitoring, but patients and carers must be aware of potential symptoms of agranulocytosis.