Medications for dementia disorders: What to know and how they work

Dementia disorders, such as Alzheimer’s disease, happen when certain specific proteins build up in the brain abnormally.

In Alzheimer’s disease, there’s an abnormal buildup of amyloid and tau proteins that result in plaques and tangles in the brain that kills nerve cells, leading to loss of memory and functioning. Worsening over time, patients with this type of dementia eventually need help with day-to-day activities.

There are two types of medications used to treat dementia disorders: those that slow down its progression and those that treat symptoms.

Medications that help slow the progression of dementia disorders

The federal Food and Drug Administration recently approved new disease-modifying therapies that fight amyloid protein in the brain.

Currently available disease-modifying therapies include donanemab and lecanemab, which are administered through an IV.

How they work

These anti-amyloid antibodies attach to and remove the toxic amyloid proteins, which build up in the brain and cause the plaque that contributes to the cognitive impairment seen in Alzheimer’s disease.

Most of the amyloid protein is removed from the brain by these treatments, leaving normal levels.

This doesn’t cure the disease or permanently stabilize it, but it does slow down the course of cognitive decline. So, we see some temporary stabilization and an altering of the course of the disease. As a result, patients have a better quality of life for more years.

While we don’t have any miracle cures, more and more of these types of disease-modifying therapies are being tested and developed.

Side effects

About 3-10% of individuals can develop symptoms like confusion, or balance or visual changes.

In rare cases, stroke-like symptoms from a brain hemorrhage may occur. These are typically related to brain swelling, which is reversible, or brain bleeding.

When to start

These treatments only work in the earliest or mild stages of cognitive impairment or perhaps up to the mild dementia stages. That’s why early identification of the cause of any cognitive impairment is critical, so that we don’t lose chances for treatment options.

Medications that treat symptoms of dementia disorders

Medications for treating symptoms of dementia disorders have been available since the mid-1990s.

Donepezil, galantamine and rivastigmine are cholinesterase inhibitors, and memantine is a NMDA antagonist. They are administered in pill form.

How they work

They help enhance different chemicals in the brain — acetylcholine and/or glutamate — which are engaged in the memory circuits. The medications help these neurotransmitters work better, which helps the memory circuits work better, thus helping the patient think better.

However, once a brain nerve cell fills up with toxic proteins and dies, these medications won’t help that dead cell. They improve the work of the cells that remain, making memory circuits work more efficiently, but they won’t change the course of the disease.

Side effects

The most common side effects for the cholinesterase inhibitors, seen in about 5-8% of individuals, are loose bowels and weight loss. Memantine can cause headache or constipation in about 5% of individuals.

When to start

The cholinesterase inhibitors work the best the earlier you start, but they all still have benefit until moderate to severe stages of dementia.

Memantine seems to work the best in moderate to severe stages of dementia.