Over-the-counter (OTC) sleep aids are widely used by people who have trouble falling or staying asleep. These medications are easy to get, do not require a prescription, and are often seen as a quick fix for occasional sleeplessness. However, for people with Alzheimer’s disease, or those at risk for dementia, the safety of these medications is a serious concern. This article explores what OTC sleep aids are, how they work, their potential risks for people with Alzheimer’s disease, and what alternatives might be safer.
## What Are Over-the-Counter Sleep Aids?
Most OTC sleep aids contain antihistamines, which are drugs originally designed to treat allergies. The most common ones are diphenhydramine (found in products like ZzzQuil and Benadryl) and doxylamine (found in Unisom). These medications cause drowsiness by blocking histamine receptors in the brain, which is why they are also used to help people sleep[1][2]. There are also herbal and supplement-based sleep aids, such as melatonin, valerian root, and chamomile, which some people use hoping for a more “natural” solution[4].
## How Do These Medications Affect the Brain?
First-generation antihistamines like diphenhydramine and doxylamine do not just block histamine in the body—they also cross into the brain. Once there, they block acetylcholine, a key chemical involved in memory, learning, and focus[1]. Acetylcholine is especially important in Alzheimer’s disease, where levels of this chemical are already low. By further reducing acetylcholine activity, these medications could make memory and thinking problems worse in people with Alzheimer’s[1].
Second-generation antihistamines, which are mainly used for allergies and not as sleep aids, were designed to avoid crossing into the brain. This makes them less likely to cause drowsiness or affect memory, but they are not typically used to help with sleep[1].
## What Does the Research Say About Dementia Risk?
Recent studies have found that regular use of first-generation antihistamines is linked to an increased risk of developing dementia, including Alzheimer’s disease[1]. A 2024 study in the Journal of Allergy and Clinical Immunology showed that people taking these medications for allergic rhinitis had a higher risk of dementia. The risk was lower with second-generation antihistamines, but still present to some degree[1]. Another study from 2023 in the Journal of Alzheimer’s Disease found that frequent use of sleep medications was associated with a higher risk of dementia in older adults, and the risk might vary by race[1].
For most healthy adults who use these medications only occasionally, the risk is considered very low. However, for older adults or those already showing signs of memory problems, the risk is more significant[1].
## Are OTC Sleep Aids Safe for People With Alzheimer’s Disease?
Given that Alzheimer’s disease involves a loss of acetylcholine in the brain, adding a medication that further blocks this chemical is generally not recommended. Doctors usually advise against long-term use of OTC sleep aids in anyone, but this is especially true for people with Alzheimer’s or those at high risk for dementia[1][2]. These medications can cause confusion, memory problems, dizziness, blurred vision, dry mouth, and next-day grogginess, which can be especially dangerous for older adults or those with cognitive impairment[2].
There is also a risk of tolerance, meaning the body gets used to the medication and it becomes less effective over time. This can lead people to take higher doses, increasing the risk of side effects and overdose[2]. Additionally, these medications can interact with other drugs commonly used by older adults, including some antidepressants and medications for mental health conditions[2].
## What About Herbal and Supplement Sleep Aids?
Some people turn to herbal remedies or supplements like melatonin, valerian root, chamomile, or magnesium, hoping for a safer alternative[4]. While these are generally considered to have fewer side effects than antihistamines, they are not without risks. Herbal supplements can interact with prescription medications, and their effects are not as well studied, especially in people with Alzheimer’s disease[4]. It is important to tell your doctor about any supplements you are taking, as they could affect your treatment plan[4].
## What Are the Alternatives?
For people with Alzheimer’s disease who have trouble sleeping, the first step is to talk to a doctor. There are prescription medications that may be safer, though all sleep medications have risks and should be used with caution. Non-drug approaches are often recommended first. These include improving sleep hygiene (such as keeping a regular sleep schedule, avoiding caffeine and screens before bed, and creating a comfortable sleep environment), treating underlying conditions that disrupt sleep (like pain, depression, or anxiety), and using behavioral therapies.
For Alzheimer’s disease specifically, there are medications called cholinesterase inhibitors (such as donepezil, rivastigmine, and galantamine) that help preserve acetylcholine in the brain and may improve memory and daily functioning[3]. These are not sleep aids, but by improving overall brain function, they might help with sleep in some people. There are also newer medications like lecanemab, which target the underlying disease process in Alzheimer’s, but these are only available by prescription and are not used for sleep[3].
## Key Points to Remember
OTC sleep aids containing antihistamines like diphenhydramine and doxylamine can increase the risk of dementia and may worsen memory and thinking problems in people with Alzheimer’s disease[1]. These medications are not recommended for long-term use in anyone, and should be used with extreme caution in older adults or those with cognitive impairment[1][2]. Herbal and supplement sleep aids may have fewer side effects, but their safety and effectiveness are not well established, especially in people with Alzheimer’s[4]. Always talk to your doctor before starting any new medication or supplement, and discuss all your current medications to avoid harmful interactions[2][4].
If you or a loved one has Alzheimer’s disease and is having trouble sleeping, the safest approach is to work with a healthcare provider to find the cause of the sleep problem and explore the safest treatment options, which may include non-drug strategies and carefully selected prescription medications if needed.
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