Neurology Experts Say There Could Be a Link Between This Common Medication and Dementia

Dementia prevention is an ever-popular topic, and for good reason: Good brain health is an important part of quality of life. It allows us to recall memories and meaningful moments. It promotes communication with loved ones. It helps us get things done and handle life with no (or, let's be honest, less) frustration.

When you think of daily habits that prevent dementia and Alzheimer's, you probably think of the big ones: exercise, managing health conditions, minimizing alcohol use, socializing and engaging in cognitively stimulating activities. Those are all super important for brain health (and other types of health, too).

What's scary, though, is that some of the health habits many of us practice-like taking certain medications that are, in fact, common-can contribute to the development of dementia. They're helpful for now, but later? You might start noticing early signs of dementia. There's one medication in particular that doctors are worried about that many people take regularly.

Below, neurologists share exactly what this medication is-and whether there are safer ways to take it if you need it.



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The Common Medication That Could Negatively Impact Brain Health

Some antihistamines have been correlated with dementia. This is "a legitimate concern," according to Dr. Fawad Mian, MD, founder at Ascend Regenerative, who is board-certified in neurology, clinical neurophysiology and sleep medicine. He points to a 2015 study in JAMA Internal Medicine that showed a 54 percent increased risk of dementia with chronic exposure to antihistamines. He adds that older adults are especially vulnerable.

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For what it's worth, not all antihistamines carry this risk. The concern is with first-generation antihistamines, such as diphenhydramine (Benadryl), hydroxyzine (Vistaril and Atarax), doxylamine (Unisom) and chlorpheniramine (Aller-Chlor, Chlor-Trimeton, Teldrin and Chlorphen). These medicines are anti-cholinergic, meaning they block the transmitter acetylcholine.

"Blocking acetylcholine activity is believed to affect memory and cognition long-term, which can increase risk of dementia," explains Dr. Johnson Moon, MD, the medical director and chair at Providence St. Jude Medical Center in Fullerton, California who is board-certified in neurology and has a subspecialty certification in clinical neurophysiology. "The newer antihistamines are more specific to histamine and less likely to cause these problems." Examples of newer antihistamines include loratadine (Claritin), cetirizine (Zyrtec) and fexofenadine (Allegra).

First-generation antihistamines aren't the only common medications that can contribute to dementia risk, either, due to their anti-cholinergic nature.

"These include prescription medications like muscle relaxers, and certain medications used for trouble sleeping or mood disorders," adds Dr. Jessica Ailani, MD, a board-certified neurologist with MedStar Health, a clinical professor of neurology at MedStar's Georgetown University Hospital and the director of the MedStar Georgetown Headache Center. "The risk for dementia exists when you use these medications daily for multiple years."

Neurologists Share Extra Warnings About Medication

Given that information, Dr. Mian urges two things: avoiding routine use of those medications, and knowing which ones can be problematic.

"[Anti-cholinergic] compounds are often found in over-the-counter sleep aids and cold medicines," he says. In other words, you might be consuming them without realizing.

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Dr. Moon agrees. "You have to be aware and read the ingredients carefully, as it is often not clear on the packaging."

Common anticholinergic ingredients found in OTC products include:

• Diphenhydramine (Benadryl, ZzzQuil, Unisom SleepTabs, Nyquil)
• Doxylamine (Unisom SleepMelts, some cold medicines)
• Chlorpheniramine (many cold/allergy medicines)
• Brompheniramine (some cough/cold syrups)

This is yet another reminder that "over-the-counter" doesn't automatically mean something is safe, can be combined with other OTC products or won't cause side effects.

"Just because a medication is available over the counter, it does not make it safe to use frequently or to rely on the treatment long-term," Dr. Ailani adds.

How To Address Your Symptoms Safely

If and when you do use an antihistamine, don't take any more than the bottle (or your doctor) says. Also, keep in mind that the dosage may depend on why you're taking the medication.

"Dosages for hydroxyzine vary depending on what it is being used for," Dr. Mian says. "For allergies, 25 mg three to four times a day, and 50 to 100 mg up to four times a day for anxiety, is how it is prescribed."

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Dr. Moon urges individuals over 65 to avoid first-generation antihistamines if at all possible, and encourages younger generations to avoid daily use. If and when you experience allergy symptoms, he advises taking one of the newer antihistamines instead.

Dr. Mian agrees. "They are less sedating, have minimal to no anticholinergic effects and do not cross the blood-brain barrier," he explains.

Plus, if you struggle with insomnia, he notes that cognitive behavioral therapy has better long-term outcomes than medications anyway, and that melatonin, magnesium and sleep hygiene are underutilized interventions.

What you do and what you consume matter. "Your brain is not a passive bystander when it comes to your daily habits," he concludes.

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Sources:

• Dr. Fawad Mian, MD is the founder at Ascend Regenerative. He's board-certified in neurology, clinical neurophysiology and sleep medicine.
• Dr. Johnson Moon, MD is the medical director and chair at Providence St. Jude Medical Center in Fullerton, California. He's board-certified in neurology and has a subspecialty certification in clinical neurophysiology.
• Dr. Jessica Ailani, MD is a board-certified neurologist with MedStar Health, a clinical professor of neurology at MedStar's Georgetown University Hospital and the director of the MedStar Georgetown Headache Center.
• Cumulative Use of Strong Anticholinergics and Incident Dementia, JAMA Internal Medicine

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This story was originally published May 22, 2026 at 10:50 AM.