The three most commonly prescribed drugs for dementia are donepezil, rivastigmine, and memantine. The first two belong to a class called cholinesterase inhibitors, which work by boosting levels of a brain chemical involved in memory and learning. Memantine works differently, protecting brain cells from a type of overstimulation that contributes to cognitive decline. These medications don’t cure dementia or stop it from progressing, but they can temporarily improve symptoms or slow the rate of decline for some people.
Donepezil: The Most Widely Prescribed
Donepezil, sold under the brand name Aricept, is by far the most commonly prescribed dementia medication. It works by blocking the breakdown of acetylcholine, a chemical messenger that nerve cells use to communicate with each other. In Alzheimer’s disease, the neurons that produce acetylcholine are among the first to be damaged, so keeping more of this chemical available in the brain helps support memory and thinking, at least for a time.
Donepezil is approved for all stages of Alzheimer’s disease, from mild to severe, which is one reason it’s prescribed so broadly. Most people start at 5 mg once daily, then increase to 10 mg after four to six weeks if the lower dose is tolerated well. A higher 23 mg dose exists for people who have been stable on 10 mg for at least three months. The once-daily dosing makes it relatively simple to manage, which matters when caregivers are often the ones keeping track of medication schedules.
The most common side effects are gastrointestinal: nausea, vomiting, diarrhea, and loss of appetite. These tend to be worse when the dose increases and often settle down after a few weeks. Starting low and stepping up gradually is the main strategy for minimizing these effects.
Rivastigmine: The Patch Option
Rivastigmine (brand name Exelon) is another cholinesterase inhibitor that works through a similar mechanism to donepezil. What sets it apart is the way it can be delivered. While it comes in capsule and liquid form, the transdermal patch has become the preferred option for many patients and caregivers.
The patch’s popularity is easy to understand when you look at caregiver experience. In studies of people who switched from oral rivastigmine to the patch, 94.3% of caregivers preferred the patch. About 92% rated it as easy or very easy to apply, and 97% found the instructions simple to follow. More than three-quarters of caregivers said the patch had minimal or no interference with daily activities, and medication forgetfulness dropped significantly. The most common complaint was adhesion problems, with about 27% of caregivers noting the patch sometimes didn’t stick well.
For someone with moderate dementia who resists taking pills or has trouble swallowing, a patch applied once daily to the back, chest, or upper arm can make a real difference in treatment consistency. Rivastigmine is approved for mild to moderate Alzheimer’s disease and for dementia associated with Parkinson’s disease.
Memantine: A Different Approach for Later Stages
Memantine (brand name Namenda) is the odd one out in this group. Instead of boosting acetylcholine, it regulates a different chemical messenger called glutamate. In a healthy brain, glutamate helps with learning and memory. But in Alzheimer’s disease, damaged cells can release too much of it, which overstimulates surrounding neurons and accelerates their death. Memantine partially blocks this process, acting like a filter that lets normal signaling through while dampening the toxic excess.
Memantine is approved for moderate to severe Alzheimer’s disease, so it’s typically introduced later in the course of the illness than donepezil or rivastigmine. Because it works through a completely different pathway, it can be prescribed alongside a cholinesterase inhibitor rather than as a replacement. Its side effect profile is notably gentler. Meta-analyses of clinical trials have found that the gastrointestinal problems common with cholinesterase inhibitors (nausea, vomiting, diarrhea, appetite loss) do not occur at higher rates with memantine compared to placebo. The most commonly reported side effects are dizziness, headache, and constipation.
Combining Medications
Many people with moderate to severe dementia end up taking both a cholinesterase inhibitor (usually donepezil) and memantine at the same time. The logic is straightforward: if the two drugs work through different mechanisms, they might provide additive benefit. The reality is more nuanced.
A meta-analysis reviewed by the American Academy of Family Physicians found that combination therapy produced a small improvement in cognitive test scores compared to donepezil alone in patients with moderate to severe Alzheimer’s disease. However, the clinical significance of that improvement was uncertain, meaning the statistical difference on paper didn’t always translate into a noticeable change in daily life. For people with mild to moderate disease, combination therapy showed no significant benefit over a single medication.
In one study of 240 patients who had been on a cholinesterase inhibitor for at least six months before adding memantine, cognitive scores showed a minimal but statistically significant improvement between three and six months after starting the combination. The typical approach is to add memantine and gradually increase it to a target dose over about four weeks. Whether the small cognitive gains justify the added cost and pill burden is a conversation that varies from patient to patient.
What These Medications Can and Cannot Do
Setting realistic expectations matters more with dementia drugs than with almost any other class of medication. These drugs do not reverse cognitive decline or halt the underlying disease process. What they can do is temporarily stabilize symptoms or slow the rate at which they worsen. For some people, this means a few extra months of being able to manage daily tasks independently, recognize family members, or participate in conversation. For others, the benefit is harder to detect.
The improvements tend to be modest by clinical measures. Over time, the disease continues to progress, and the medications become less effective as more brain cells are lost. Most clinicians recommend continuing treatment as long as the person is tolerating it and the caregiver or family feels it’s still helping, since there’s often a noticeable dip in function when the medication is stopped.
A newer class of drugs, monoclonal antibodies that target the amyloid plaques thought to contribute to Alzheimer’s, has recently entered the market. These work in a fundamentally different way and are approved only for early-stage disease with confirmed amyloid buildup. They remain far less commonly prescribed than the three medications above due to limited availability, high cost, and the need for regular brain imaging to monitor for side effects. For the vast majority of people currently living with dementia, donepezil, rivastigmine, and memantine remain the standard pharmacological options.