Clozapine-induced electroencephalogram changes as a function of clozapine serum levels.


Journal Article

Specific electroencephalogram (EEG) changes during clozapine therapy were prospectively studied in a cohort of 50 chronic state hospital patients with schizophrenia who were randomly assigned to one of three nonoverlapping clozapine serum level ranges (50-150 ng/mL, 200-300 ng/mL, and 350-450 ng/mL). EEGs were obtained before clozapine was instituted, and after 10 weeks of treatment. Fifty-three percent of patients showed EEG changes during the 10-week study period. We observed three seizures (6%), one in a patient on 900 mg (serum level 320 ng/mL) clozapine, and two in patients with lower clozapine serum levels (200-300 ng/mL) who had prior histories of seizures and inadequate valproate coverage. Thirteen percent of patients developed spikes with no relationship to dose or serum level of clozapine. Fifty-three percent of patients developed slowing on EEG. Compared to plasma levels below 300 ng/mL, a clozapine serum level between 350 and 450 ng/mL led to more frequent and more severe slowing. The EEG slowing correlated with observed sleepiness, although this factor was not sufficient to explain the severity of high-dose effects.

Full Text

Duke Authors

Cited Authors

  • Freudenreich, O; Weiner, RD; McEvoy, JP

Published Date

  • July 1997

Published In

Volume / Issue

  • 42 / 2

Start / End Page

  • 132 - 137

PubMed ID

  • 9209730

Pubmed Central ID

  • 9209730

Electronic International Standard Serial Number (EISSN)

  • 1873-2402

International Standard Serial Number (ISSN)

  • 0006-3223

Digital Object Identifier (DOI)

  • 10.1016/s0006-3223(96)00298-3


  • eng