From the Guidelines

Risperidone is the best medication for agitation in Alzheimer's disease.

Atypical antipsychotic agents are recommended for control of problematic delusions, hallucinations, severe psychomotor agitation, and combativeness in patients with Alzheimer's disease 1.
Risperidone (Risperdal) is a commonly used atypical antipsychotic agent, with an initial dosage of 0.25 mg per day at bedtime and a maximum dosage of 2 to 3 mg per day, usually twice daily in divided doses 1.
Olanzapine (Zyprexa) and Quetiapine (Seroquel) are also atypical antipsychotic agents that can be used to treat agitation in Alzheimer's disease, but Risperidone is generally considered the first-line treatment due to its efficacy and safety profile 1.

Typical antipsychotic agents should be avoided if possible due to their association with significant side effects, including extrapyramidal symptoms and tardive dyskinesia 1.
Mood-stabilizing drugs, such as Trazodone (Desyrel) and Divalproex sodium (Depakote), can be used as alternatives to antipsychotic agents for control of severe agitated, repetitive, and combative behaviors 1.
Cholinesterase inhibitors, such as Donepezil (Aricept), Rivastigmine (Exelon), and Galantamine (Reminyl), are primarily used to treat cognitive symptoms of Alzheimer's disease, but may also have some benefits in reducing agitation 1.

The American Psychiatric Association practice guideline on the use of antipsychotics to treat agitation or psychosis in patients with dementia recommends the use of atypical antipsychotic agents, such as Risperidone, as a first-line treatment for agitation in Alzheimer's disease 1.
The guideline also emphasizes the importance of careful assessment and monitoring of patients with dementia, as well as consideration of the potential benefits and harms of antipsychotic medication 1.

From the Research

There are several medication options available for the treatment of agitation in Alzheimer's disease, including:
- Antipsychotics, such as risperidone, aripiprazole, and quetiapine 2
- Selective serotonin reuptake inhibitors, such as citalopram 3, 2
- Brexpiprazole, an oral antipsychotic that has been approved for the treatment of agitation associated with dementia due to Alzheimer's disease 4
- Other medications, such as mirtazapine, prazosin, and lithium, which have been discussed as potential treatment options 5, 6, 2

The efficacy and safety of these medications vary, with some studies showing significant improvements in agitation symptoms, but also reporting adverse events such as falls, extrapyramidal symptoms, stroke, and mortality 5, 3
Brexpiprazole has been shown to be effective in reducing agitation symptoms, with a significant reduction in the Cohen-Mansfield Agitation Inventory total score at week 12 from baseline compared with placebo 4
Citalopram has also been shown to be effective in reducing agitation symptoms, with significant improvements on the Neurobehavioral Rating Scale agitation subscale and the modified Alzheimer Disease Cooperative Study-Clinical Global Impression of Change 3

A sequential drug treatment algorithm for agitation and aggression in Alzheimer's and mixed dementia has been proposed, which recommends sequential trials with risperidone, aripiprazole or quetiapine, carbamazepine, citalopram, gabapentin, and prazosin 2
The algorithm also provides guidance on the use of electroconvulsive therapy, optimization of existing cholinesterase inhibitors/memantine, and use of pro re nata medications 2
It is recommended that medications be used with caution and with careful consideration of the potential risks and benefits, and that non-pharmacological approaches be used as the primary management strategy for agitation in Alzheimer's disease 5