Benadryl for Sleep: What to Know About This Antihistamine’s Sleepy Side Effects
Key takeaways:
Benadryl (diphenhydramine) is an over-the-counter (OTC) antihistamine that treats allergies and cold symptoms. Some people also take Benadryl as a sleep aid since it causes drowsiness.
The recommended Benadryl dosage for sleep is 50 mg by mouth 30 minutes before bedtime in adults and kids age 12 years and older. You shouldn't take Benadryl for longer than 2 weeks (14 days) at a time.
Always check the “Drug Facts” label on OTC products. This helps ensure you’re not doubling up on doses and accidentally taking multiple medications that contain diphenhydramine.
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At some point, you or a loved one have likely experienced trouble sleeping. And if it happens frequently, you may be experiencing insomnia — a condition involving trouble falling asleep, staying asleep, or a combination of the two.
Not getting enough sleep can put a damper on your daily life. You may have even tried an over-the-counter (OTC) medication — like the allergy medication Benadryl (diphenhydramine) — to help you sleep. In fact, many people rely on Benadryl’s side effect of drowsiness for sleep support. But is it safe to consistently take Benadryl for sleep?
What is Benadryl used for?
Benadryl is an OTC antihistamine that treats seasonal allergies, cold symptoms, and allergic reactions in kids and adults. It’s readily available on the shelves of most pharmacies and supermarkets.
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Benadryl also comes in several formulations. You can find it as an oral tablet, capsule, and liquid. Dissolving and chewable tablets also exist. A topical cream is even an option. In more serious cases, it can be given as an injection into a muscle or vein in a hospital.
You can also find several other products that contain diphenhydramine at the pharmacy. It’s found in many combination cough and cold products, all of which can make you sleepy. What’s more, it’s the active ingredient in ZzzQuil, a brand-name OTC product that is marketed to treat short-term sleep problems in adults and kids age 12 and older.
Why does Benadryl make you sleepy?
Benadryl is a first-generation (older) antihistamine. It works by blocking histamine, a natural chemical in your body. Histamine release causes symptoms such as itching, sneezing, congestion, and runny nose. Blocking histamine helps relieve these symptoms.
First-generation antihistamines cross a natural barrier in your body that shields your brain from unwanted substances. Benadryl can slip through this protective gate, which is why it causes drowsiness. Unisom SleepTabs (doxylamine) is another example of a first-generation antihistamine that does this. Doxylamine is found in a variety of OTC sleep aids.
Claritin (loratadine), Zyrtec (cetirizine), and Allegra (fexofenadine) are examples of “newer” generation antihistamines. These don’t reach the brain as much, so they’re less likely to cause drowsiness. In fact, these antihistamines are typically recommended over Benadryl for allergies because they’re non-drowsy options.
Good to know: If you’re looking for the antihistamine that’s the least likely to cause drowsiness, Allegra is typically the best bet.
Other side effects of Benadryl
Sleepiness is only one Benadryl side effect. In some cases, it can cause other side effects. These include:
Dry mouth
Dizziness
Constipation
Coordination problems
Blurred vision
Memory problems
Trouble urinating
Headache
Reach out to your pharmacist and prescriber about any side effects that you’re concerned about or don’t go away.
Is it OK to take Benadryl for sleep?
In general, yes. But there are some conflicting recommendations.
The FDA recognizes diphenhydramine as a safe and effective OTC sleep aid for adults and kids age 12 and older. But diphenhydramine products, such as ZzzQuil and Benadryl, should only be used for occasional sleeplessness and for less than 2 weeks (14 days) at a time.
Taking Benadryl: Hear from pharmacists about typical Benadryl (diphenhydramine) dosages for adults and kids.
Risks and warnings: Like all medications, Benadryl may cause side effects. Learn about the most notable ones and how to manage them.
How much is too much? Taking excess Benadryl increases the risk of side effects. Here’s what to do if you or a loved one take too much Benadryl.
On the other hand, the American Academy of Sleep Medicine (AASM) doesn’t recommend taking Benadryl or other OTC antihistamines regularly for insomnia. A number of studies show a lack of evidence to support their use for sleep in adults.
Is it harmful to take Benadryl every night?
It’s best to avoid taking Benadryl every night for sleep, if possible.
Over time, your body can build up tolerance to it. After a while, it may not help you sleep. You can also experience drowsiness the next day, or a “hangover” effect, after taking Benadryl — making it difficult to get through work, school, and other daily activities.
How much Benadryl is OK to take as a sleep aid?
A typical Benadryl or ZzzQuil dosage for sleep is 50 mg by mouth 30 minutes before bedtime. This gives it some time to start working.
One question you may have for your pharmacist is: Will 25 mg of Benadryl make me sleepy? Depending on your response to the medication, yes. You could take a 25 mg dose instead.
Keep in mind that you should only take one Benadryl product at a time. Diphenhydramine is found in many combination products, such as Tylenol PM Extra Strength (acetaminophen / diphenhydramine) and Advil PM (ibuprofen / diphenhydramine). Always check the “Drug Facts” label on OTC medications to make sure you aren’t doubling up on diphenhydramine from multiple sources. Taking too much Benadryl raises the risk of side effects.
As a precaution, it’s a good idea to reach out to your prescriber and pharmacist before trying Benadryl for sleep. They can also check if Benadryl interacts with any of your current medications.
Good to know: If you think you or a loved one took too much Benadryl, call a healthcare professional right away. You can also contact Poison Control online or at 1-800-222-1222. Seek emergency medical attention immediately if someone experiences a seizure, has trouble breathing, or can’t wake up after taking Benadryl.
Who shouldn’t take Benadryl as a sleep aid?
Benadryl causes drowsiness in most people. But it can actually cause the opposite effect in kids. It can make them hyperactive or agitated. This is one of the reasons why Benadryl should be avoided as a sleep aid in kids younger than 12.
On the other end of the age spectrum, the American Geriatrics Society recommends avoiding Benadryl in adults age 65 and older. Side effects such as dizziness, drowsiness, and confusion can be especially problematic for older adults, as they can raise the risk of falls. Some research has also linked overusing medications like Benadryl to an increased risk of dementia, but this hasn’t been proven.
For people with certain eye conditions, Benadryl can also cause a serious condition known as acute angle-closure glaucoma (AACG). It’s uncommon, but it can lead to permanent vision loss if left untreated. If you have narrow-angle glaucoma, it’s best to avoid Benadryl because you have a raised risk of experiencing AACG.
Alternative sleep aids for insomnia
It’s ideal to focus on sleep hygiene before trying any sleep medications. This involves creating a routine with healthy sleep habits. Turning off screens 1 hour before sleep and avoiding exercise too close to bedtime are a couple of examples.
If these strategies don’t work, OTC sleep aids like Benadryl are generally acceptable to try next. But the list of choices expands beyond this antihistamine. Melatonin is a natural supplement option, but there isn’t a lot of evidence showing it helps with chronic insomnia. Valerian root and chamomile are also options, but they don’t have much supporting data either.
If you need more than an OTC sleep aid, there are a variety of prescription medications that manage insomnia. Ambien (zolpidem) and Belsomra (suvorexant) are a couple of examples. Talk with a healthcare professional to see if one is right for you. Keep in mind that many prescription sleep medicines come with a risk of dependence, so it’s important to know how to use them safely.
When to see a healthcare professional about difficulty sleeping
It’s natural to feel frustrated if you’ve been struggling with sleepless nights. When it comes to Benadryl, reach out to a healthcare professional if you’ve consistently been taking it for 2 weeks or more. Benadryl isn’t well suited for long-term use.
If healthy sleep habits and OTC sleep aids aren’t doing the trick, then it may be time to see a healthcare professional. Sometimes there could be a medical condition causing insomnia. So it’s a good idea to get it checked out. Or you may benefit more from a prescription sleep aid.
What’s more, certain medications could also be keeping you up at night. For instance, if you have a cold and recently started taking the decongestant Sudafed (pseudoephedrine), you can experience sleeping problems — especially if you take it later in the evening. A pharmacist can check your current medication list to see if any could be the culprit.
Frequently asked questions
Benadryl will likely help you sleep for about 4 to 6 hours. That’s because this is the time frame Benadryl’s effects typically last. But research shows Benadryl may not improve the quality of your sleep. This means you may not feel that well rested when you wake up.
The “safest” sleep aid isn’t widely established. Rozerem (ramelteon), though, is one sleep medication that’s considered safe to take long-term. It’s well tolerated overall and shouldn’t cause dependence. Rozerem is a prescription medication that works by activating certain melatonin receptors in the brain to help you fall asleep.
The AASM recommends several prescription medications for insomnia. If you need help staying asleep, Belsomra and Silenor (doxepin) are top options. Sonata (zaleplon), Halcion (triazolam), and Rozerem are go-to medications for falling asleep. For help falling and staying asleep, your healthcare professional may recommend Ambien (zolpidem), Lunesta (eszopiclone), or Restoril (temazepam).
The bottom line
Adults and kids age 12 and older can take Benadryl (diphenhydramine) as a short-term, over-the-counter (OTC) sleep aid. But it’s typically not a go-to medication for chronic insomnia. Adults age 65 and older, people with narrow-angle glaucoma, and kids under 12 should avoid taking Benadryl for sleep. Dry mouth, dizziness, and constipation are a few examples of side effects to be aware of before starting Benadryl.
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References
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Glaucoma Research Foundation. (2022). When people with glaucoma should avoid allergy and decongestant medications.
Katayose, Y., et al. (2012). Carryover effect on next-day sleepiness and psychomotor performance of nighttime administered antihistaminic drugs: A randomized controlled trial. Human Psychopharmacology.
MedlinePlus. (2019). Histamine: The stuff allergies are made of.
National Center for Complementary and Integrative Health. (2020). Valerian.
National Center for Complementary and Integrative Health. (2024). Chamomile.
National Heart, Lung, and Blood Institute. (2022). What are sleep deprivation and deficiency?
Richardson, G. S., et al. (2002). Tolerance to daytime sedative effects of H1 antihistamines. Journal of Clinical Psychopharmacology.
Sateia, M. J., et al. (2017). Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: An American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine.
Sicari, V., et al. (2023). Diphenhydramine. StatPearls.
The Procter and Gamble Manufacturing Company. (2024). Zzzquil nighttime sleep-aid - diphenhydramine hydrochloride capsule, gelatin coated [package insert]. DailyMed.
Wang, D., et al. (2024). Molecular mechanism of antihistamines recognition and regulation of the histamine H1 receptor. Nature Communications.
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