Patient: Male, 75-year-old Final Diagnosis: Dementia with Lewy bodies Symptoms: Parkinsonism Medication:— Clinical Procedure: — Specialty: Neurology Objective: Unusual clinical course Background: Antidopaminergic medications, including antipsychotics, are known to worsen motor and neuropsychiatric symptoms, including cognition and psychosis, in patients with dementia with Lewy body (DLB). The intensity of worsened clinical symptoms may vary and can result in mortality in certain situations. There have been some reports supporting clozapine, quetiapine and pimavanserin use in psychosis control in this population. Case Report: We describe the case of 75-year-old man with diagnosis of DLB and the post-treatment outcome with olanzapine for psychosis during hospitalization. He experienced worsened cognitive and motor functions. Discontinuation of olanzapine resulted in resolution of the clinical worsening. Further, re-initiation of Pimavanserin helped treat his hallucinations. He returned back to his baseline during a follow-up visit in the clinic at 1 month after discharge. Further, we incorporated the use of Best Practice Alert (BPA) as a part of the electronic health record (EHR) system to help providers identify patients prone to neuroleptic sensitivity and help select appropriate medications to treat psychosis in this patient population. Conclusions: Administration of antipsychotics in patients with parkinsonism, especially DLB, requires close clinical monitoring and judicious use. Awareness of morbidity and mortality associated with such use is of importance, especially during hospitalization. From our experience, we incorporated use of BPA, which can help providers make judicious choices while treating this patient population. Pimavanserin, which is FDA-approved for psychosis in Parkinson’s disease, could be a potential safe and effective treatment option in this patient population.