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Allergy Medications and Dementia Risk: What the Research Says

Older adult reviewing a list of medicines with a pharmacist at a pharmacy counter, with unlabeled bottles nearby

Maybe you've seen the headline: a common allergy medicine linked to dementia. And maybe you've been reaching for a nighttime pain reliever or sleep aid most nights for years. Suddenly you're wondering what's in that bottle.

It's a fair question, and an unsettling one to sit with. So let's walk through what the research actually found, what it didn't find, and what questions to bring to your doctor.

What Are Anticholinergic Drugs?

Anticholinergic drugs block acetylcholine (a chemical messenger that carries signals in the body and brain). Several kinds of medicine work this way, including some older antihistamines, some antidepressants, and some bladder medicines.

Diphenhydramine, the active ingredient in Benadryl, is one of them. According to MedlinePlus, diphenhydramine is also used for sleep trouble in adults. That's why it shows up in many nighttime pain relievers and sleep aids. MedlinePlus also notes that it generally shouldn't be used by adults 65 and older, except for serious allergic reactions, because other medicines are safer.

What the Study Found

The research that got people talking was published in JAMA Internal Medicine. Researchers followed 3,434 adults age 65 and older who didn't have dementia when the study began. They tracked pharmacy records for 10 years of medicine use.

The most common strong anticholinergics people used were tricyclic antidepressants, first-generation antihistamines, and bladder medicines. The finding: higher cumulative use was associated with a higher risk of dementia. The highest-use group, with the equivalent of more than about three years of daily use, had the highest risk. The National Institute on Aging reported that about 23 percent of participants developed dementia, usually Alzheimer's.

What It Doesn't Mean

This kind of study shows an association, not proof that the medicine causes dementia. The National Institute on Aging notes that more studies are needed. The results also focus on regular use over years, not an occasional dose for hives or a bad allergy day.

So there's no need to panic. It is a good reason to look closely at your medicine cabinet. Check nighttime products too, since you may not think of them as allergy medicine.

Allergy Medicine Options to Ask About

Newer antihistamines work differently. A review in the World Allergy Organization Journal explains that second-generation antihistamines cross into the brain far less. These include loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra). It calls them the antihistamines of choice for allergic rhinitis (hay fever).

Our post on how allergy medications work compares antihistamines, decongestants, and nasal steroid sprays. And never stop or change a prescribed medicine without talking to your healthcare provider first.

Needing Less Medicine in the First Place

Lowering your exposure to allergens can take pressure off your symptoms. Nasal irrigation is a drug-free way to rinse allergens from your nose. If dust mites are a trigger, zippered covers from our AllergyCare Cotton collection help block allergen in your bed. And if you'd like a treatment that changes how your immune system responds, ask your allergist about allergy shots or drops. For more ideas, see our Practical Guide to Allergy-Free Living.

Your next step: Gather every medicine you take, including sleep aids and nighttime pain relievers, and bring the bottles to your next appointment. Ask your doctor or pharmacist which ones are anticholinergic and whether there's a better fit for you.

Wishing you the best of health,
Cheryl

Sources

Medical Disclaimer: The information on this page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider — such as an allergist or your primary care physician — before making changes to your allergy management plan, starting new treatments, or if you have questions about a medical condition. In the event of a severe allergic reaction or anaphylaxis, call 911 or your local emergency number immediately and use an epinephrine auto-injector if one has been prescribed.

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