EEG alterations during treatment with olanzapine.

The aim of this naturalistic observational study was to investigate EEG alterations in patients under olanzapine treatment with a special regard to olanzapine dose and plasma concentration. Twenty-two in-patients of a psychiatric university ward with the monodiagnosis of paranoid schizophrenia (ICD-10: F20.0), who received a monotherapy of olanzapine were included in this study. All patients had a normal alpha-EEG before drug therapy, and did not suffer from brain-organic dysfunctions, as verified by clinical examination and cMRI scans. EEG and olanzapine plasma levels were determined under steady-state conditions (between 18 and 22 days after begin of treatment). In 9 patients (40.9%), pathological EEG changes (one with spike-waves) consecutive to olanzapine treatment were observed. The dose of olanzapine was significantly higher in patients with changes of the EEG than in patients without changes (24.4 mg/day (SD: 8.1) vs. 12.7 mg/day (SD: 4.8); T = -4.3, df = 21, P < 0.001). In patients with EEG changes, the blood plasma concentration of olanzapine (45.6 μg/l (SD: 30.9) vs. 26.3 μg/l (SD: 21.6) tended to be also higher. The sensitivity of olanzapine dosage to predict EEG changes was 66.7%, the specificity 100% (Youden-index: 0.67). EEG abnormalities during olanzapine treatment are common. These are significantly dose dependent. Thus, EEG control recordings should be mandatory during olanzapine treatment with special emphasis on dosages exceeding 20 mg per day, although keeping in mind that EEGs have only a limited predictive power regarding future epileptic seizures.
AuthorsDetlef Degner, Michael A Nitsche, Frank Bias, Eckart Rüther, Udo Reulbach
JournalEuropean archives of psychiatry and clinical neuroscience (Eur Arch Psychiatry Clin Neurosci) Vol. 261 Issue 7 Pg. 483-8 (Oct 2011) ISSN: 1433-8491 [Electronic] Germany
PMID21431467 (Publication Type: Journal Article)
Chemical References
  • Antipsychotic Agents
  • Benzodiazepines
  • olanzapine
  • Adolescent
  • Adult
  • Aged
  • Antipsychotic Agents (blood, pharmacology, therapeutic use)
  • Benzodiazepines (blood, pharmacology, therapeutic use)
  • Brain Waves (drug effects)
  • Chromatography, High Pressure Liquid (methods)
  • Electroencephalography (methods)
  • Female
  • Humans
  • Male
  • Middle Aged
  • ROC Curve
  • Schizophrenia (drug therapy, physiopathology)
  • Young Adult

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