The present disclosure is related to methods of treating agitation and/or aggression and/or associated symptoms in subjects with dementia, including, dementia associated with Alzheimer’s disease. The method includes administering to a subject in need thereof a dextromethorphan compound, or a pharmaceutically acceptable salt thereof, in combination with quinidine, or a pharmaceutically acceptable salt thereof. The disclosure in certain aspects is also related to compositions that are used for treating agitation and/or aggression and/or associated symptoms in subjects suffering from Alzheimer’s disease.本揭露內容係有關於治療失智症個體的躁動行為及/或攻擊行為及/或相關症狀之方法,該失智症係包括與阿滋海默氏(Alzheimer)症相關的失智症。該方法包括對於有需要的一個體投予一種右旋美索芬(dextromethorphan)化合物或其一藥學上可接受的鹽類,及組合投予奎尼丁(quinidine)或其一藥學上可接受的鹽類。本揭露內容就特定方面而言亦有關於用於治療阿滋海默氏(Alzheimer)症患者的躁動行為及/或攻擊行為及/或相關症狀之組成物。