For a decade and a half, Alicia Brown lived with relentless insomnia. Falling asleep could take several exhausting hours, and on nights when she woke before dawn, sleep rarely returned.
When the worst stretches hit, she sometimes turned to over-the-counter nighttime allergy or cold medicines, including products like Benadryl, hoping their sedating effect would help her finally rest.
Brown, 57, told Our News Outlet: “It helped quiet my mind, and when that happened, I could usually get about five solid hours. I’d probably use it once every six weeks, for a few nights at a time.”
For years, she did not view the occasional routine as especially concerning.
That changed earlier this year when Brown, a nurse and healthcare administrator who works closely with dementia patients, encountered research that cast those familiar medications in a troubling new light.
A growing body of studies has associated anticholinergic drugs — a widely used class of medications — with an increased risk of dementia. Brown quickly recognized that diphenhydramine, the active ingredient in Benadryl and the sleep aid she had occasionally depended on, falls into that category.
The finding hit especially hard because Brown’s own mother is living with dementia.
After that, she said, continuing to use the medication as a sleep solution “was no longer an option.”
Alicia Brown, 57, told Our News Outlet that she stopped taking anticholinergics to sleep after 15 years due to concerns about their alleged links to dementia
‘I see the impact daily of people living with dementia,’ she said. ‘The risk of of these medicines is not worth it. Losing who you are, who you were, your memories, your relationships, it is devastating.
‘If I can do something to avoid a greater risk, I’m definitely going to do that.’
Few people may have heard the term anticholinergic. Yet the category includes some of America’s most familiar medicines.
They include diphenhydramine, the antihistamine in Benadryl and many nighttime products including some versions of Unisom, Tylenol PM and Advil PM; and prescription drugs such as oxybutynin (Ditropan) and tolterodine (Detrol) for overactive bladder, and the antidepressants amitriptyline (Elavil) and paroxetine (Paxil).
Other prescription anticholinergics include solifenacin (Vesicare) for bladder problems and procyclidine (Kemadrin) for Parkinson’s symptoms.
Benadryl’s parent company, Kenvue, told Our News Outlet in a statement: ‘The health and safety of consumers is our top priority. Diphenhydramine-containing medicines have a long history of safe and effective use when taken as directed.
‘Based on our review of available evidence, we have not found that diphenhydramine increases dementia risk when used as directed on the label.
‘We will continue to evaluate safety information on an ongoing basis as part of our commitment to consumer safety.’
Indeed, an estimated one in five Americans takes some form of anticholinergic medication.
Found in most ‘PM’ sleep aids and allergy medications, diphenhydramine is one of the anticholinergic drugs experts are most concerned about being linked to dementia
But, despite how common they are, there is mounting evidence that these medications may harm the brain when taken over long periods of time. One study found older adults taking anticholinergic drugs had a 47 percent greater risk of developing mild cognitive impairment (MCI), often a precursor to dementia.
Anticholinergics work by blocking acetylcholine, a chemical messenger used by the nervous system to control a wide range of functions. Depending on the drug, this can help calm an overactive bladder, reduce nausea, ease allergy symptoms or cause drowsiness.
However, acetylcholine also plays a crucial role in the brain.
By blocking it there, the drugs can interfere with communication between brain cells involved in memory, attention and executive function.
And it is this, experts believe, that increases the risk of cognitive decline.
Each year, more than half a million Americans are diagnosed with MCI and around one in five will go on to develop dementia within a year.
Doctors still don’t fully understand why some people develop cognitive decline while others do not. But numerous potentially modifiable factors have been linked to a greater risk, including smoking, heavy drinking, physical inactivity, obesity, high blood pressure, diabetes, hearing loss and social isolation.
Indeed, experts estimate that as many as 40 percent of dementia cases could be prevented or delayed by tackling such risks.
But doctors warn there is another potential risk hiding in plain sight: the medicines people take.
Many patients don’t realize that common anticholinergic drugs may pose particular problems when taken regularly for months or years at a time – for example, using an over-the-counter sleep aid every night to fall asleep.
Millions of people use commonly-found medicines to help them get to sleep
‘I actively de-prescribe these, as most people don’t need them and they are hazardous to many older people,’ California-based internal medicine physician and author Dr John La Puma told Our News Outlet.
Taking these drugs daily for years, whether for sleep, allergies or bladder control, is where the danger lies, not occasional use for a bad allergy attack or a few sleepless nights.
According to research, the risk appears to rise with prolonged daily use and greater cumulative exposure, particularly in older adults and in people taking several drugs with anticholinergic effects at the same time.
‘There is a cumulative, dose-dependent association with higher dementia or MCI risk,’ La Puma told Our News Outlet. ‘There is also, especially for people most at risk, imaging evidence of real brain change.’
What is less clear is whether the damage can be undone. Short-term memory and thinking problems caused by anticholinergics may improve once the drugs are stopped, but scientists do not yet know whether years of exposure can cause lasting changes in the brain – or whether an elevated dementia risk eventually returns to normal.
‘We know that strong anticholinergics may cause confusion and memory problems, especially in older people,’ Dr Parth Bhavsar, family medicine physician and medical director at TeleDirectMD, told Our News Outlet.
‘The issue is how exposure over the years contributes to neurodegeneration and makes it faster, if the brain is predisposed or partially represents an underlying condition.’
Complicating efforts to understand the long-term risks is the sheer scale – and often hidden nature – of their use.
More than 600 prescription and over-the-counter medications are thought to have anticholinergic properties. And because many, such as Benadryl, can be bought without a prescription, studies relying on prescription records may substantially underestimate how many people are exposed.
Their use is also far from confined to the elderly: estimates suggest up to 43 percent of older adults and 26 percent of younger adults regularly take medications with anticholinergic effects.
Meanwhile, a separate major study of more than 280,000 people aged 55 and over found that long-term exposure to certain types of anticholinergic drugs was associated with an increased risk of dementia.
And it is far from an isolated finding.
A 2020 analysis pooling data from nearly 650,000 patients across five countries found long-term anticholinergic use was associated with a 46 percent higher risk of dementia.
More recently, a 2025 review involving more than 3.6 million patients found a 20 percent increased risk among people taking anticholinergic drugs for bladder problems.
Older people and those already experiencing cognitive problems are thought to be particularly vulnerable.
But another concern is that patients may unknowingly be taking several anticholinergic drugs at once – perhaps a prescription medicine alongside an over-the-counter product for allergies or sleep.
‘Many older adult patients are using multiple anticholinergic medications such as diphenhydramine for sleep, bladder antispasmodic agents, muscle relaxants and older generation antidepressants,’ Dr Michael DeShields, a New Jersey-based internal medicine physician, told Our News Outlet.
While researchers cannot say for certain that the drugs cause dementia, DeShields said it would be safer to reduce unnecessary anticholinergic use where possible, and if there is a concern about cognitive decline speak to a prescribing physician about the possibility of switching to an alternative.
Alzheimer’s gene APOE4 carriers taking anticholinergics (red) showed a steeper decline in memory over 36 months than non-users without the allele (black). Anticholinergic users without the gene (blue) and carriers not on the drugs (green) also declined, but less sharply
Alicia Brown says she has now been off anticholinergics for about eight months.
She has experimented with essential oil blends and herbal patches, although she admits: ‘They are nowhere near as effective, despite some people swearing by them.’
‘They don’t quiet the “noise” that keeps me awake – the constant replay of the day, organizing what is coming during the week, the grocery list for Mom, all of those typical things.’
She is still adapting, keeping her bedroom cooler and darker and using white noise to help her drift off.
‘Whatever I need to do since anticholinergics are just something I’m not willing to risk unless the science eventually points away from it being an issue,’ she said. ‘I’m going to find other options.’
