Due to demographic changes we are faced with several challenges as an increasing prevalence of dementia patients. We report on a medication review of a patient with Alzheimer's disease as well as Lewy body dementia. The intake of risperidone was interrupted instead of a dose reduction which was recommended by the psychiatrist to improve mobility. As an adverse event the patient developed serious psychiatric symptoms which were treated in an acute care facility. We discussed several alternative treatment options (pipamperon, melperon, haloperidol, risperidone, clozapine, olanzapine, aripiprazol, and quetiapin) in a case conference. Due to a short half life period and insignificant anticholinergic effects we decided to choose quetiapin. Despite a small number of taken drugs we identified several potential drug related problems which were solved in a multipartite health care professional team.