It is generally believed that agranulocytosis, a major problem with clozapi
ne treatment, will tend to occur dose-dependently once it develops in an in
dividual. Therefore, despite clinical progress obtained, the drug has to be
discontinued and treatment shifts to another drug. We report on the case o
f a 29-year-old woman with DSM-IV undifferentiated schizophrenia who develo
ped agranulocytosis after 5 years of 300 mg/day clozapine treatment. The dr
ug was withdrawn and two trials with thioridazine and olanzapine were unsuc
cessful. Four months after clozapine suspension, we decided to make a furth
er trial, reintroducing clozapine titrated up to 500 mg/day. The patient's
symptoms improved and blood leukocytes remained within the normal range aft
er eight months. Copyright (C) 2000 John Wiley & Sons, Ltd.