Every so often, alarming headlines come up about potential causes of Alzheimer’s disease. These stories sometimes focus on everyday habits, like nose-picking or taking the common over-the-counter medication diphenhydramine, better known by its brand name Benadryl.

Diphenhydramine is a type of drug called an antihistamine, which works by blocking histamines — chemicals in the body that cause allergy symptoms. It’s mainly used to treat allergies but can also help with insomnia and motion sickness.

It can be hard to know what to do with all this information, especially if you have a family history of Alzheimer’s disease. Here’s what you should know about diphenhydramine and if taking it puts you at risk for cognitive decline — a gradual loss of memory, thinking, or decision-making abilities.

Is There a Connection Between Benadryl and Alzheimer’s Disease?

There may be a connection between using diphenhydramine and an increased risk of Alzheimer’s disease. The possibility of a relationship between diphenhydramine and Alzheimer’s is based on a study from 2015.

This study analyzed the connection between anticholinergic drugs and dementia. When they’re in your body, anticholinergic drugs block a chemical called acetylcholine. This chemical plays many important roles in the body. It can help you learn and form memories and make your muscles contract. Many medications fall under the category of anticholinergic drugs. Diphenhydramine is only one of these. Other allergy medicines fall into this category, as well as certain antidepressants, antinausea drugs, and more.

The researchers in the 2015 study examined 3,500 people who were 65 years old or older. They looked at all the medications the study participants had taken during the 10 years before the study, then tracked their health for at least seven years. Eight hundred people developed dementia. Researchers found a connection between the amount of anticholinergic drugs a person took and their risk of developing dementia. Those who took them for three years or more were 54 percent more likely to be diagnosed with dementia.

Other studies have confirmed and expanded on this work. One 2019 study from the journal Scientific Reports examined a National Health Insurance Service database. The researchers confirmed that anticholinergic drugs raised the risk of developing dementia. However, they also found that having between 0 and 49 doses of an anticholinergic drug over a year did not significantly raise the risk of dementia.

In 2023, a study from BMC Geriatrics found that the number of anticholinergic drugs someone takes also matters regarding health risks. The researchers analyzed data from more than 12,000 people and found that there was a greater risk of developing dementia for those exposed to more of these medications.

In addition to these studies, some anticholinergic drugs make older adults more likely to fall and may also cause confusion. Some older people also experience problems with short-term memory and reasoning when they take certain anticholinergic medications. These side effects are similar to some of the symptoms of Alzheimer’s and dementia.

Are These Studies Conclusive?

There’s still a lot we don’t know about anticholinergic drugs, brain health, and developing dementia or Alzheimer’s disease. Just because two factors tend to happen together doesn’t mean that one causes the other. When these studies say that higher levels of anticholinergic drug use often come before a dementia or Alzheimer’s diagnosis, that may be true. However, it doesn’t mean that the drugs are causing dementia.

One explanation might be that something else is causing both of those outcomes. For instance, people who have certain health conditions that require anticholinergic medications could already be at a higher risk of developing dementia.

There’s still a lot we don’t know about what causes Alzheimer’s, and more research is needed to help us understand it better.

Is It Safe To Use Benadryl?

If you’re concerned about using diphenhydramine or any anticholinergic drug, ask your doctor for medical advice. They can help you understand what risk level you might be facing and make the best decision for your health. You and your health care provider may want to consider the questions below before you make any decision about diphenhydramine. Then, you can make an informed decision about what to take and when.

What Is Your Overall Anticholinergic Exposure?

Some drugs have stronger anticholinergic effects than others. In fact, there’s a tool called the Anticholinergic Burden Scale that you and your doctor can use as a reference. Drugs that may be anticholinergic are labeled with a 1, and those that are known anticholinergics are classified as level 2 or level 3. Some of these medications may be drugs you take on occasion, whereas others may be something you take daily. You and your doctor can talk through your medications to understand your exposure.

What Kinds of Anticholinergic Drugs Do You Take?

A study from 2022 shows that only certain types of anticholinergic drugs may be connected to a higher risk of developing dementia. These include antidepressants, epilepsy medications, and drugs that treat overactive bladder (antidiuretics). Although we can’t say anything for sure, your risk may be lower if you use anticholinergic drugs for other purposes.

How Much Medication Do You Need?

Part of your considerations when it comes to diphenhydramine is how much you need to take. If you need to take medication as a sleep aid every night, you might make a different choice than if you only use it occasionally for allergies.

Are There Alternatives?

You may want to discuss alternatives to anticholinergic drugs if you are concerned about how often you need them or the number of anticholinergic drugs you’re currently taking. There are several over-the-counter allergy medications on the market, including fexofenadine (Allegra), loratadine (Claritin), and cetirizine (Zyrtec). In general, these are recommended as an everyday allergy medication over diphenhydramine because they don’t cause major drowsiness. These medications also have a lower score on the Anticholinergic Burden Scale compared to diphenhydramine.

If you take an anticholinergic medication for another health issue, you can ask your doctor about alternative options. There may not be appropriate alternatives, based on your situation. Depending on the medication use, the benefits may outweigh any potential risks.

Talk With Others Who Understand

On myALZteam, the social network for people with Alzheimer’s and their loved ones, more than 86,000 members come together to ask questions, give advice, and share their stories with others who understand life with Alzheimer’s disease.

Are you concerned about using Benadryl because of its connection to Alzheimer’s disease? Share your experience in the comments below, or start a conversation by posting on your Activities page.