Some research has found a link between the risk of dementia in older adults and a class of medications that includes Benadryl. But there’s no research to suggest that taking Benadryl when younger can increase your risk of Alzheimer’s.
Benadryl is an over-the-counter antihistamine that contains the active ingredient diphenhydramine. People often use it to treat allergies. Because it causes drowsiness, some people take it as a sleep aid.
Many brand-name drugs contain diphenhydramine. A few of these include:
- Tylenol PM
Diphenhydramine and other first-generation antihistamines are part of a class of drugs called anticholinergics. While some research has linked many anticholinergics to an increased risk of dementia in older people, it’s not clear whether Benadryl use can lead to Alzheimer’s. This article explores ongoing research.
Dementia vs. Alzheimer’s disease
Although they have much in common, dementia and Alzheimer’s disease aren’t the same.
Dementia is not a specific diagnosis. It refers to a broad collection of symptoms that impact daily activities, memory, language, and cognition.
Alzheimer’s is one of several types of dementia. It’s a specific diagnosis associated with certain symptoms and treatments.
Most of the research cited in this article focuses on the link between anticholinergics and dementia.
One of the first studies to report a link between dementia and anticholinergics, including first-generation antihistamines like Benadryl, was published in 2015.
The authors of this
The results suggest a link between total anticholinergic use and the development of dementia over a 10-year period among people over age 65. According to the authors, there was a link between increased doses of anticholinergics and an increased risk of developing dementia, including Alzheimer’s.
The authors reported increased brain atrophy and dysfunction linked to the use of medium or strong anticholinergics. They found that participants who took these drugs were also more likely to experience overall declines in health.
The authors of a
- Some research has linked anticholinergics like diphenhydramine (Benadryl) to an increased risk of dementia in older adults.
- Several studies focus on the link between medium or strong anticholinergics and dementia risk. Some researchers consider antihistamines to be in this group, while others do not.
- A few studies have found no link between antihistamines like Benadryl and dementia.
More research is needed to confirm whether or not Benadryl increases the risk of dementia, and in particular, Alzheimer’s.
The American Geriatrics Society listed diphenhydramine in a
- blurred vision
- dry mouth
- urinary retention
Among older people with cognitive or mobility impairments, the side effects listed above could contribute to an increased risk of a fall or accident.
Experts generally consider second- and third-generation antihistamines safer options for treating allergies. These include:
- loratadine (Claritin)
- cetirizine (Zyrtec)
- fexofenadine (Allegra)
They carry a lower risk of side effects such as drowsiness.
People with Alzheimer’s should avoid Benadryl and other medications that contain diphenhydramine when possible. These medications may aggravate Alzheimer’s symptoms, such as confusion.
People with Alzheimer’s may also be more likely to experience side effects when taking Benadryl.
Finally, prolonged use of diphenhydramine among people with Alzheimer’s could potentially contribute to a more rapid decline in mental function.
It’s possible that taking Benadryl or other anticholinergics when younger increases your risk of developing Alzheimer’s as an older adult.
Most of the studies reviewed here only analyzed anticholinergic use over several months or years. These results do not necessarily apply to younger individuals taking diphenhydramine over a lifetime. More research is needed.
Which other medications are linked to Alzheimer’s?
Benzodiazepines are another class of medication with a link to dementia. These drugs have sedative properties, and doctors typically prescribe them to treat anxiety and sleep disorders.
As with anticholinergics, the link between benzodiazepines and Alzheimer’s isn’t totally clear. But benzodiazepines are also likely to make symptoms associated with dementia and cognitive decline worse.
Diphenhydramine (Benadryl) is a common over-the-counter allergy medication. It’s part of a class of drugs called anticholinergics that research has linked to dementia in older people.
The research isn’t clear as to whether taking Benadryl can increase your risk of Alzheimer’s, though. One study found no link at all, but more research is needed to confirm this result.
In any case, doctors discourage the use of Benadryl among older adults due to the risk of side effects. A second-generation antihistamine might be a safer option if you’re looking for an over-the-counter allergy medication.