Clozapine, is widely prescribed for treatment of refractory schizophrenia, but its use may be limited by potentially serious adverse effects. The most feared complication remains agranulocytosis [absolute neutrophil count (ANC) < 500/mm3], which occurs in 1% of patients. Guidelines recommend immediate cessation until the granulocyte count normalizes, but little is known about the subsequent treatment and the possibility of restoring clozapine.

To know procedures that allow clozapine rechallenge after induced agranulocytosis in refractory schizophrenia.

We present a clinical case of agranulocytosis and evolution after simple reinstitution of clozapine.

A 38-year-old woman diagnosed refractory schizophrenia. After 10 years with clozapine (300 mg/day), we find neutropenia (ANC 1420/mm3) in a monthly control blood count with progression to agranulocytosis (ANC 460/mm3) in the following month. We suspend clozapine and started olanzapine (20 mg/day) with restoration of haematological values in a period of one month. The patient had psychotic decompensation at two months after the change with lack of response to different psychopharmacological strategies for five months. According to the hematology department we decided to re-introduce clozapine (200 mg/day) in combination with olanzapine with complete clinical remission. Between the 3rd and 9th week after rechallenge we observe a progressive decline in ANC, while remaining within the range of normal. From the 9th week and in the last 6 months neutrophil counts remained stable.

Although, more research is needed to establish the safety to rechallenge of clozapine after agranulocytosis, it must be an alternative to consider when other treatment strategies fail.

The authors have not supplied their declaration of competing interest.