[Mnestic impairment under olanzapine overdosage in an elderly patient].

Atypical antipsychotics are increasingly used for the treatment of elderly patients. However, there are only few studies on their efficacy and side effects in this patient group. The case of a 67-year old patient is presented, in whom under treatment with olanzapine in usual dosage, serum level increased into the toxic range. This olanzapine overdosage was accompanied by severe impairments in visual and verbal memory and by an increase of slow-frequency activity in the EEG. Both alterations may be attributed to the anticholinergic effects of olanzapine and reversed rapidly after dose reduction and normalization of the olanzapine serum level.