RESUMEN
Clozapine is an atypical antipsychotic drug with a very low incidence of extrapyramidal effect, used in the treatment of schozophrenic patients refractory or intolerant to classical neuroleptics. Its use is limited due to the potential risk of producing agranulocytosis in 1 to 2 per cent of patients. Despite the severity of this complication, the Federal Drug Administration allowed its use as long as iots prescription is associated to a drug surveillance program. Two patients had a transitory leukopenia with less than 2000 leukocytes/ml and less than 1000 neutrophyls/ml, that reverted after discontinuing the drug. One patient, whose case is described, had a severe agranulocytosis with less than 500 neutrophyls/ml that required hospital admission