Unisom for Sleep in Menopause: Two Different Drugs, One Name

What is actually in Unisom?

Unisom is a brand name, not a single drug, and the active ingredient changes with the product. Unisom SleepTabs contain doxylamine succinate 25 mg. Unisom SleepMelts and SleepMinis contain diphenhydramine 25 mg per tablet or capsule. Both ingredients are first-generation antihistamines, the older kind of allergy medicine that causes drowsiness.

The uses printed on the labels are modest. SleepTabs "helps to reduce difficulty in falling asleep." The diphenhydramine products are "for relief of occasional sleeplessness." None of the three labels lists hot flashes, night sweats or menopause as a use.

There is also Unisom PM Pain, which adds acetaminophen 325 mg to diphenhydramine 50 mg per caplet; its label carries a liver warning and says not to use it with any other drug containing acetaminophen.

The practical lesson is to read the active ingredient line, not the front of the box. Diphenhydramine is also the ingredient in many allergy pills and "PM" pain relievers, and the diphenhydramine labels warn against using them with any other product that contains it, "even one used on skin."

How does Unisom make you sleepy?

Unisom makes you sleepy as a side effect. Doxylamine and diphenhydramine block histamine, a chemical that causes allergy symptoms and also helps keep the brain alert. MedlinePlus describes diphenhydramine as an antihistamine that works by blocking histamine, used for allergy and cold symptoms and also for insomnia in adults.

The same drugs also block acetylcholine, a messenger the body uses for memory, bladder control, digestion and saliva. That is what "anticholinergic" means, and it explains much of the side-effect list: dry mouth, constipation, trouble urinating and, in some people, confusion.

The American Geriatrics Society describes the whole group of first-generation antihistamines, doxylamine and diphenhydramine included, as "highly anticholinergic." That label matters more as we age, as the safety section below explains.

Does Unisom actually help you sleep?

For diphenhydramine, the evidence says the benefit is small. When the American Academy of Sleep Medicine (AASM) reviewed the trials for its 2017 guideline, every sleep measure for diphenhydramine 50 mg fell below its threshold for clinical significance, meaning too small to matter much. It suggests clinicians not use diphenhydramine for chronic insomnia, a weak recommendation.

The guideline rated the quality of that evidence as low and concluded that "the majority of well-informed patients would not use diphenhydramine over no treatment." Doxylamine, the ingredient in SleepTabs, doesn't appear in the guideline at all, so there is no AASM verdict on it either way.

There's also the question of how long the drowsiness lasts. In a small 2002 study, 15 healthy men aged 18 to 50 took diphenhydramine 50 mg twice a day. Daytime sleepiness was clearly higher on day 1, but by day 4 it was no different from placebo. The authors wrote that tolerance to the sedation "develops with remarkable rapidity."

That study measured daytime sleepiness in young and middle-aged men, not bedtime use in women, so it can't be applied directly. The 2023 Beers Criteria, though, list tolerance among the reasons to avoid these drugs as sleep aids in older adults.

Is Unisom a good fit for menopause insomnia?

Unisom wasn't designed or tested for menopause insomnia. I searched Europe PMC for trials of doxylamine or diphenhydramine for sleep in perimenopausal or postmenopausal women and found none. That is a limit of my search, not proof that none exist, but it means there's no direct evidence for women in midlife.

The bigger issue is what's waking you. If it's hot flashes and night sweats, an antihistamine doesn't treat them; the labels don't list them as a use. Our hot flashes guide covers the treatments that do have evidence, and treating the flashes may help sleep more than sedation.

The labels themselves point in the same direction. Each one says to stop and ask a doctor if sleeplessness persists continuously for more than two weeks, adding that "insomnia may be a symptom of serious underlying medical illness." One cause worth ruling out in midlife is sleep apnea.

What are the side effects of Unisom?

The common side effects of Unisom's ingredients come from their antihistamine and anticholinergic actions. For diphenhydramine, MedlinePlus lists dry mouth, nose and throat, drowsiness, dizziness and muscle weakness, and says to call a doctor right away for vision problems or difficulty or pain when urinating. The Beers Criteria add confusion and constipation.

Some of these overlap with symptoms many of us already have in midlife, such as dry eyes, a dry mouth and constipation. It's worth noticing whether a new sleep aid makes any of them worse.

Next-morning drowsiness is the other practical concern. The SleepTabs label says not to use it "unless you have time for a full night's sleep," and not to drive or operate machinery while using it. MedlinePlus says not to drive until you know how diphenhydramine affects you.

Why do geriatric experts say to avoid Unisom after 65?

Geriatric experts list both of Unisom's ingredients among medicines to avoid after 65. The American Geriatrics Society's 2023 Beers Criteria name doxylamine and diphenhydramine among first-generation antihistamines that adults 65 and older should avoid, citing reduced clearance with age, tolerance when used for sleep, and the risk of confusion and other anticholinergic effects.

The same entry adds a line that matters for younger readers too: "Cumulative exposure to anticholinergic drugs is associated with an increased risk of falls, delirium, and dementia, even in younger adults." It advises caution in the "young-old," not just the oldest patients.

MedlinePlus is similar for diphenhydramine: it "generally" shouldn't be used in older adults except to manage serious allergic reactions, because it isn't as safe or effective as other options, and anyone 65 or older should talk to their doctor about the risks and benefits.

What about the link between Unisom and dementia?

The dementia link comes from studies of long-term, cumulative use, not a single bad night. The best known followed 3,434 adults aged 65 or older in Seattle for an average of 7.3 years, using pharmacy records to measure 10 years of anticholinergic use. First-generation antihistamines were among the most common drugs counted.

This was an observational study, so it shows an association, not proof that the drugs cause dementia. One possible alternative explanation is that these drugs are often taken for insomnia and depression, which can be early signs of undiagnosed dementia. The authors tried to account for this by excluding the last 12 months of use, and the higher risk still appeared with heavy use of first-generation antihistamines, not only antidepressants.

The participants were also 65 or older and the risk showed up only with years of heavy use. Still, insomnia in midlife can last for years, and a nightly habit of Unisom for sleep can start long before 65, which is why the cumulative picture is worth knowing now.

Who should check with a doctor before taking Unisom?

The Unisom labels list who should ask a doctor first. Ask before use if you have a breathing problem such as emphysema or chronic bronchitis, glaucoma, or trouble urinating due to an enlarged prostate. Ask a doctor or pharmacist if you take sedatives or tranquilizers, and avoid alcohol while using it.

• Other medicines: the SleepTabs label also lists any other sleep aid, other antihistamines and "any other drugs." Don't combine it with another doxylamine product, or a diphenhydramine product with another diphenhydramine product, including creams.
• Pregnancy or breastfeeding: the labels say to ask a health professional first. Pregnancy is still possible in perimenopause, as our perimenopause pregnancy guide explains.
• Overdose: the labels say to get medical help or contact a Poison Control Center right away.

What do sleep doctors recommend instead of Unisom?

Sleep doctors recommend a non-drug treatment first. The 2017 AASM guideline says that "all patients with chronic insomnia should receive CBT-I as a primary intervention." CBT-I is cognitive behavioral therapy for insomnia, a structured program that changes the habits and thoughts that keep insomnia going. It's covered in detail in our CBT-I guide.

If you and your doctor decide a medicine makes sense, the same guideline gives weak recommendations for several prescription options, compared side by side in our sleeping pills for menopause insomnia article. If you've been using Unisom for sleep, bring the box to that appointment so the doctor sees exactly which ingredient you've been taking.

Where to go from here

If hot flashes are behind the waking, start with our hot flashes guide. If it's 3 a.m. wakefulness with a busy mind, how to fall back asleep at 3 a.m. and night-time anxiety in menopause are good next reads. For other bedtime options people reach for, see melatonin and trazodone.

For how all of this fits into the bigger picture of midlife sleep, start at the complete perimenopause and menopause sleep guide.

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