Hae W Shin and Tania Beltran Papsdorf
Psychotropic medications are often used in various psychiatric and neurological conditions. Potential risks of
seizures or altered mental status are low but have been reported with these medications. However, increased dose
of these medications were not known to predispose to epileptiform encephalopathy. A 79 year old female with a
history of mild dementia, major depressive disorder and anxiety was brought into our tertiary medical center by her
family for a two week history of worsening depression and anxiety, superimposed on acute psychosis after minor
dose adjustment of mirtazapine and donepezil. Neurological evaluation revealed moderate encephalopathy without
any underlying metabolic, infectious or structural cerebral abnormalities. However, an electroencephalogram
showed frequent bifrontally predominant spikes and polyspikes and slow wave discharges as well as moderate
background slowing. Subsequently, an electroencephalogram was normalized after stopping both mirtazapine and
donepezil. The patient's mental status was also improved back to her baseline and was able to return home on
hospital day 15. To our knowledge, our case is the first report of denovo epileptiform encephalopathy from increased
doses of mirtazapine and donepezil which were previously well tolerated in an elderly patient. New onset of
psychosis and encephalopathy in these patients should prompt evaluation with EEG.
