Are OTC Medications Putting Seniors at Risk for Dementia?

Published September 24th, 2020 by Dr. Brady McNulty, PharmD, BCGP
Fact Checked by
Chris Riley
Updated Date: Apr 16th, 2021

Do you know what is in your grandparents’ medicine cabinet? Odds are you would find at least one drug in a class called anticholinergics. These medications can be used for many reasons, including treatment for allergies and sleep issues. A new study from the University of California San Diego School of Medicine reports that these medications may increase the risk of “cognitive decline, particularly in older adults at greater risk for Alzheimer’s disease.”

Which medications are we talking about, and who is most at risk?

Anticholinergic Medications are Extremely Common

When perusing the over the counter medication aisles or picking up a prescription at your local pharmacy, you may have run across several of these kinds of drugs in different areas on the shelves. 

There are more than six hundred drugs in this category. For example: if you are going out fishing on a boat, you might consider taking Dramamine® (dimenhydrinate) to treat your seasickness. If that was not effective, your doctor might prescribe scopolamine patches. 

If you have allergies, you may have already tried Chlor-Trimeton® (chlorpheniramine) or Benadryl® (diphenhydramine). If you are suffering from a sleep disorder, you might have tried another form of diphenhydramine called Sominex. Diphenhydramine is often also contained in products bearing a PM label, such as Advil PM® or Tylenol PM®.

Dementia is an Irreversible Illness

Memory loss in the elderly can be a common occurrence. As we age, our bodies change, and that includes the brain and its efficiency. Some mild forgetfulness and slower learning as we age can be perfectly normal. 

Dementia is a clinical syndrome composed of memory, language, and behavioral issues that affect daily life. More than 135 million people worldwide might suffer from dementia by the year 2050. Alzheimer’s Disease, a specific kind of dementia, is the most common. 

Over the course of the disease, a person can become weak, losing their ability to eat, have a loss of appetite, and experiencing incontinence. Confusion, anger, and sleep disturbances are all typical for late-stage dementia. 

Robin Williams suffered from a form of dementia called Lewy Body Dementia. The complications of forgetfulness, paranoia, insomnia, anxiety, and tremors ultimately played a role in the actor’s decision to end his life.

Dementia is progressive, and there is no cure, so our best hope is to minimize a person’s risk factors and try to catch the disease early. The average life expectancy for someone with dementia is eight to ten years from when it started.

Risk Factors for Dementia

Some risk factors for dementia are in our control, including our life choices like smoking and exercising. Some risk factors are beyond our control, such as aging, genetics, and gender.

The most significant risk factor for dementia is merely getting old. Women are at higher risk than men. Genetics also play a role, too, as people of South Asian and African descent are more likely than others to develop the disorder. Additionally, more than twenty individual genes have been associated with an increased risk of developing dementia. 

Our health plays an important role, too. High blood pressure, obesity, diabetes, and high cholesterol also increase the risk of dementia later in life. 

In contrast, according to the Alzheimer’s Society, the risk is lowest for people who include “physical exercise, not smoking, drinking alcohol only in moderation (if at all), and maintaining a healthy diet and weight” in their lifestyle choices.

So What Did the New Study Show?

The team at University of California San Diego School of Medicine found that these drugs “may be associated with an increased risk of cognitive decline, particularly in older adults at greater risk for Alzheimer’s disease.”

They found, over the course of a decade, that people taking at least one of these kinds of medication were 47 percent more likely to experience a mild cognitive impairment when compared to people who took none. None of the people in the study showed any signs of cognitive impairment at the beginning. 

The team also looked at certain predictive biomarkers for Alzheimer’s Disease and discovered that people with those biomarkers were four times more likely to show signs of cognitive impairment! Those with other genetic risk factors were 2.5 times more likely.

The presence of these biomarkers indicates that something is already wrong in the basal forebrain, the part of the brain that produces acetylcholine, which promotes thinking and memory. The drugs discussed in this article, “further deplete the brain’s store of acetylcholine,” according to one of the researchers

Older People Are Using Medications Well Above Normal Doses

Another reason to inquire about an older person’s medications is that more than half of the study group took over twice the recommended dose. Almost twenty percent took at least four times the recommended dose!

The Takeaway 

Any medication carries a risk, no matter how easily accessible it may be. You should always follow the directions on the package or label, making sure never to exceed the recommended dosages. If you have a question about your medications, interactions, and risks, don’t hesitate to contact your healthcare provider. 

Our older populations are most at risk for potentially inappropriate medication use based on their age, health and other factors. 

Making wise decisions now regarding your health, life choices, and medication use will potentially have a HUGE impact on your health and quality of life later. 


1. LaFee S. Common Class of Drugs Linked to Increased Risk of Alzheimer’s Disease. UC Health - UC San Diego.,cognitive%20decline%2C%20particularly%20in%20older. Published 2020. Accessed September 20, 2020.

2. Ghossein N, Kang M, Lakhkar A. Anticholinergic Medications. Published 2020. Accessed September 20, 2020.

3. Do Memory Problems Always Mean Alzheimer's Disease?. National Institute on Aging. Published 2020. Accessed September 20, 2020.

4. Robbins R. How Lewy Body Dementia Gripped Robin Williams. Scientific American. Published 2020. Accessed September 20, 2020.

5. The progression of Alzheimer's disease. Alzheimer's Society. Published 2020. Accessed September 20, 2020.

Published September 24th, 2020 by Dr. Brady McNulty, PharmD, BCGP
Fact Checked by
Chris Riley
Updated Date: Apr 16th, 2021

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