Reactions 985 - 24 Jan 2004

Antipsychotics associated withEEG abnormalities

Olanzapine, and to a lesser extent haloperidol, areassociated with EEG abnormalities, whereas quetiapineis very rarely associated with such abnormalities, reportresearchers from Germany.

The researchers conducted a retrospective studycomparing rates of EEG abnormalities in patientsreceiving quetiapine at a mean ± SD dose of563.6 ± 210.6 mg/day (n = 22), olanzapine at a meandose of 15.7 ± 10.5 mg/day (37) or haloperidol at a meandose of 9.1 ± 3.5 mg/day (22). These three groups werealso compared to a control group of age- and sex-matched controls (n = 30). Diagnoses of patientsreceiving quetiapine, olanzapine or haloperidol did notdiffer significantly.

Overall, one (5%) patient receiving quetiapine, five(23%) receiving haloperidol, 13 (37%) receivingolanzapine and two (7%) in the control group had anabnormal EEG. In addition, four (11%) of those receivingolanzapine had clear epileptiform activity on EEG.Regarding the EEG abnormalities, the differencebetween the quetiapine and olanzapine groups washighly significant, as was the difference between thecontrol and olanzapine groups. The researchers alsoidentified a statistically significant dose-related effect onEEG findings in the olanzapine group but not in thequetiapine or haloperidol groups.

In conclusion, the researchers say "olanzapine has adose dependent seizure risk and haloperidol a modestrisk of EEG alterations". In addition, they note the "verylow rate of EEG abnormalities" seen with quetiapine, andsay this may be an alternative treatment option forpatients with a diagnosis of epilepsy or seizures withpsychosis.Amann BL, et al. EEG abnormalities associated with antipsychotics: a comparisonof quetiapine, olanzapine, haloperidol and healthy subjects. HumanPsychopharmacology: Clinical and Experimental 18: 641-646, No. 8, Dec2003 800970535

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Reactions 24 Jan 2004 No. 9850114-9954/10/0985-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved