Delirium is very common in hospitalized patients with Parkinson's disease. Prevention plays a very important role, but sometimes medication therapy is unavoidable. In this case, several medications are contraindicated due to their anti-dopaminergic effect. These effects can lead to very pronounced extrapyramidal symptoms. If necessary, therapy with quetiapine may be administered. It is important to be aware of patient comorbidities before prescribing a medication to treat delirium.