Fall Risk in Older Adults on Sedating Antihistamines: Prevention Strategies

Every year, nearly 36 million falls happen among adults 65 and older in the U.S. About one in four of them will fall. Many of these falls aren’t accidents-they’re side effects of medications people think are harmless. One of the biggest hidden dangers? First-generation sedating antihistamines like diphenhydramine (Benadryl), chlorpheniramine, and brompheniramine. These drugs are sold over the counter, often used for allergies, colds, or sleep. But for older adults, they can be deadly.

Why Sedating Antihistamines Are Dangerous for Older Adults

First-generation antihistamines don’t just block histamine in the nose or throat. They cross the blood-brain barrier and hit the central nervous system hard. This causes drowsiness, slowed reaction time, poor balance, and dizziness-all of which make falls much more likely. Older adults are especially vulnerable because their bodies process these drugs differently. Liver and kidney function slow down with age, so the drugs stick around longer. Diphenhydramine, for example, has a half-life of 8.5 hours in young adults but stretches to 13.5 hours in people over 65. That means drowsiness can last well into the next day, even if they took it the night before.

The American Geriatric Society has labeled these drugs as “potentially inappropriate” for older adults in their Beers Criteria. Why? Because they don’t just cause sleepiness. They also trigger dry mouth, blurred vision, constipation, confusion, and even delirium. A 2025 study tracking nearly 200,000 older adults found that 32% filled a prescription for a vestibular suppressant-mostly first-gen antihistamines-and 8% fell within 60 days. That’s not a small risk. That’s a pattern.

The Science Behind the Risk: First-Gen vs. Second-Gen

Not all antihistamines are the same. Second-generation options like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) were designed to stay out of the brain. They work just as well for allergies but cause far less sedation. Here’s the key difference:

• First-generation (diphenhydramine, chlorpheniramine): Strong anticholinergic activity (score of 3-4 on the Anticholinergic Cognitive Burden Scale). High fall risk.
• Second-generation (fexofenadine, loratadine): Minimal anticholinergic activity (score of 0-1). Low to no increased fall risk.

A 2018 meta-analysis in Osteoporosis International found that first-gen antihistamines increased the risk of injurious falls by 54% and fractures by 43%. In contrast, second-gen antihistamines showed no significant increase in falls. Even cetirizine, often thought of as safe, causes drowsiness in 14% of older adults-compared to just 6% with fexofenadine. So if you need an antihistamine, fexofenadine is the safest bet.

How Common Is This Problem?

Surprisingly, very common. Despite clear warnings, first-generation antihistamines are still widely used. Sales data from 2024 shows diphenhydramine is the third most purchased OTC sleep aid in the U.S. among people 65+, with over 28 million units sold annually. That’s $142 million in sales-mostly to people who don’t realize they’re putting themselves at risk.

Even worse, doctors still prescribe them. A 2019 study found that 12.7% of older adult visits included a prescription for a first-gen antihistamine-almost the same rate as for younger adults. That’s a “one-size-fits-all” approach that ignores how aging changes drug metabolism. Primary care doctors prescribe them more often than dermatologists, even though allergy patients are the main users. The disconnect between evidence and practice is alarming.

What Can Be Done? Prevention Strategies That Work

The good news? This risk is preventable. The CDC’s STEADI initiative (Stopping Elderly Accidents, Deaths & Injuries) gives a clear three-step plan: STOP, SWITCH, REDUCE.

• STOP: If someone is taking diphenhydramine for sleep or allergies, ask if it’s really needed. Many older adults take it out of habit or because they’ve been told it’s “safe.” Often, it’s not.
• SWITCH: Replace first-gen antihistamines with second-gen ones. Fexofenadine and loratadine are just as effective for allergies and don’t increase fall risk. For sleep, skip the pills entirely-try sleep hygiene instead.
• REDUCE: If a sedating antihistamine must be used, use the lowest dose possible (e.g., 12.5 mg instead of 25 mg of diphenhydramine) and take it at night, not during the day.

Non-Drug Alternatives That Actually Work

You don’t need pills to manage allergies or sleep. Here are proven, safer options:

• Nasal saline irrigation: Rinsing the nose with salt water reduces allergy symptoms by 35-40%, according to JAMA Otolaryngology.
• Allergen-proof bedding: Covers for pillows and mattresses reduce dust mite exposure by 83%.
• HEPA air filters: Remove 99.97% of airborne allergens like pollen and pet dander.
• Non-drug sleep strategies: Stick to a consistent bedtime, avoid caffeine after noon, keep the bedroom cool and dark, and get morning sunlight to reset your circadian rhythm.

These aren’t just “nice to have.” They’re clinically proven alternatives that reduce the need for risky medications.

Environmental Changes to Prevent Falls

Even if you can’t stop the medication right away, you can reduce the chance of a fall. Simple home changes make a huge difference:

• Install grab bars in bathrooms-reduces fall risk by 28%.
• Improve lighting in hallways, stairs, and bathrooms-cuts falls by 32%.
• Remove tripping hazards: loose rugs, clutter, extension cords.
• Use non-slip mats in the shower and near the sink.

These fixes cost little but save lives. A fall isn’t just a stumble-it can mean a broken hip, months in rehab, or even death. One in three falls among older adults leads to serious injury.

Role of Pharmacists and Care Teams

Pharmacists are often the first to spot dangerous medication use. Many older adults don’t tell their doctors about OTC drugs they take. A “brown bag review”-where patients bring all their pills, supplements, and OTC meds to the pharmacy-can uncover an average of 3.2 high-risk medications per person. Studies show pharmacist-led reviews reduce fall risk by 26%.

Doctors and nurses should ask three simple questions during annual check-ups:

1. Have you fallen in the past year?
2. Do you feel dizzy or unsteady when standing up?
3. Are you taking any over-the-counter sleep aids or allergy meds?

If the answer is yes to any, it’s time for a medication review. The Medicare Annual Wellness Visit now requires documentation of high-risk medication use-including antihistamines-as part of fall risk screening. This is a policy shift that’s finally catching up to the science.

What’s Next? New Hope on the Horizon

There’s promising research coming. Two new antihistamines-AGS-2025-01 and FEX-AGE-101-are in Phase II trials. Early results show they cause 89% less drowsiness than diphenhydramine while still blocking histamine effectively. These are designed specifically for older adults, with minimal brain penetration.

But we don’t have to wait. Right now, we have the tools to prevent thousands of falls. We just need to use them.

Next Steps for Families and Caregivers

If you’re caring for an older adult:

• Do a “brown bag” medication review-collect every pill, bottle, and supplement they take, and bring it to their pharmacist or doctor.
• Check labels for diphenhydramine, chlorpheniramine, or doxylamine-these are common hidden ingredients in cold, flu, and sleep meds.
• Replace OTC sedating antihistamines with non-drug allergy and sleep solutions.
• Make home safety a priority: install grab bars, remove rugs, add nightlights.
• Ask: “Is this medication still needed?” every time a new one is added.

Falls aren’t inevitable. They’re preventable. And often, the most dangerous thing in an older adult’s medicine cabinet isn’t a prescription-it’s the bottle labeled “Benadryl.”

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