Tegan Smedley, PharmD, BCPS, APh
Written by Jennifer Gershman, PharmD, CPh, PACS | Reviewed by Tegan Smedley, PharmD, BCPS, APh
Key takeaways:
- Benadryl (diphenhydramine) is an antihistamine that treats allergies and cold symptoms. Some people also take Benadryl as an over-the-counter (OTC) sleep aid since it causes drowsiness.
- The recommended Benadryl dosage for sleep is 25 mg to 50 mg by mouth at bedtime in adults and kids ages 12 years and older. Benadryl should not be taken for longer than 2 weeks at a time.
- Always check the “Drug Facts” label on OTC products to make sure you’re not taking too much Benadryl. 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 can easily be found on the shelves of local pharmacies and supermarkets.
Benadryl also comes in several formulations. It’s available as an oral tablet, capsule, and liquid. Dissolving and chewable tablets also exist. In more serious cases, it can be given as an injection into a muscle or vein in a hospital.
You can also find other common products that contain diphenhydramine at the pharmacy. It’s found in many combination cough and cold products, all of which can make you sleepy. But it’s also the active ingredient in ZzzQuil, a brand-name OTC product that is marketed to treat short-term sleep problems in adults and kids 12 years and older.
Why does Benadryl make you sleepy?
Benadryl is a first-generation antihistamine. It works by blocking histamine, a natural chemical in your body. Histamine causes symptoms like itching, sneezing, congestion, and runny nose. So blocking histamine helps manage those allergy symptoms.
Older, first-generation antihistamines cross a natural barrier in your body that shields your brain from unwanted substances. Benadryl is one of these medications that can slip through this protective gate, which is why it can cause drowsiness. Doxylamine (Unisom SleepTabs) is another example of a first-generation antihistamine that does this. Like Benadryl, doxylamine is found in a variety of OTC sleep aids.
Loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) 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 are non-drowsy options.
Other side effects of Benadryl
Sleepiness is only one Benadryl side effect. In some cases, it can cause other side effects you should be aware of. These include:
- Dry mouth
- Dizziness
- Constipation
- Coordination problems
- Blurred vision
- Loss of appetite
- Trouble urinating
- Headache
Reach out to your pharmacist and healthcare provider 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’s some conflicting recommendations.
The FDA recognizes diphenhydramine as a safe and effective OTC sleep aid for adults and kids ages 12 years 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.
However, the American Academy of Sleep Medicine doesn’t recommend taking Benadryl regularly to treat insomnia in adults. A number of studies show a lack of evidence to support Benadryl for sleep in adults.
Is it harmful to take Benadryl every night?
If possible, it’s best to avoid taking Benadryl every night for sleep.
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?
The recommended dose of Benadryl or ZzzQuil for sleep is usually 50 mg by mouth 30 minutes before bedtime. This gives it some time to kick in. Depending on your situation and response to the medication, you could take a lower 25 mg dose instead.
Also, keep in mind that you should only take one Benadryl product at a time. Diphenhydramine is contained 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 can raise the risk of side effects.
As a precaution, it’s a good idea to reach out to your healthcare provider and pharmacist before trying Benadryl for sleep. They can also check if Benadryl interacts with any of your current medications.
If you think you or a loved one took too much Benadryl, call your healthcare provider or Poison Control at 1-800-222-1222. Seek emergency medical attention immediately if someone experiences a seizure, has trouble breathing, or can’t wake up.
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 years old.
On the other end of the age spectrum, the American Geriatrics Society recommends avoiding Benadryl in adults ages 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. 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 usually safe for occasional use. But the list of options 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.
If you need something more than an OTC sleep aid, there are a variety of prescription medications that manage insomnia. Talk with your healthcare provider 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 provider 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 your healthcare provider 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 your healthcare provider. 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’ve taken it later in the evening. Your healthcare provider and pharmacist can check your current medication list to see if any could be the culprit.
The bottom line
Benadryl can be taken short-term as an OTC sleep aid in adults and kids ages 12 years and older. But it’s typically not a go-to medication for chronic insomnia. Adults ages 65 years and older, people with narrow-angle glaucoma, and kids under 12 should avoid Benadryl for sleep. Dry mouth, dizziness, and constipation are a few examples of side effects you should be aware of before starting Benadryl.
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