In January 2025, three allergy specialists published a striking recommendation in the World Allergy Organization Journal.
They called diphenhydramine, the active ingredient in Benadryl and most nighttime pain relievers, a public health hazard.
Their conclusion was blunt. The drug should be phased out of routine use because safer, equally effective options are widely available.
Diphenhydramine is a first-generation antihistamine. That means it crosses into the brain and blocks a signaling chemical called acetylcholine, an effect known as anticholinergic activity.
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That mechanism explains the drowsiness. It also explains side effects like dry mouth, blurred vision, constipation, urinary retention and confusion.
Diphenhydramine remains everywhere. The review authors report it appears in more than 300 formulations in the United States, most sold over the counter, with over 1.5 million prescriptions written each year.
Why the concern is louder for older adults
The half-life, meaning how long the body takes to clear the drug, stretches from about 4 hours in children to as long as 18 hours in older adults.
A dose taken at bedtime can still linger well into the next day.
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Long-term use in people over 65 has been linked to higher dementia risk.
In a 2015 study in JAMA Internal Medicine, adults 65 and older with the heaviest cumulative use of strong anticholinergic drugs had a 54 percent higher risk of developing dementia than non-users. The study shows association, not proof of cause.
The American Geriatrics Society Beers Criteria, a widely used guide that flags common medications prescribed to older adults, lists first-generation antihistamines as potentially inappropriate for people over 65.
Impaired driving worse than alcohol
The review authors also flag risk behind the wheel. They cite research showing diphenhydramine impaired driving more than alcohol, and note the European Union categorizes the drug as "do not drive."
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What to switch to
Second-generation antihistamines were designed to treat allergies without crossing into the brain.
Cetirizine (sold as Zyrtec), loratadine (Claritin) and fexofenadine (Allegra) are all available over the counter.
According to the review, they control sneezing, itching and runny nose as well as or better than diphenhydramine, with far less sedation.
The authors note that fexofenadine in particular has essentially no brain penetration.
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Anyone taking Benadryl regularly, especially older adults, should talk with their doctor before stopping.
For older adults, current Beers Criteria guidance is to avoid diphenhydramine altogether.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.