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Unisom vs. Benadryl: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on October 15, 2023
Unisom is primarily a sleep aid, while Benadryl is an antihistamine used for allergies; both can cause drowsiness.

Key Differences

Unisom and Benadryl are both over-the-counter medications. While Unisom is primarily marketed as a sleep aid, Benadryl is most commonly known as an antihistamine for allergies. Both have the potential side effect of causing drowsiness, which is why Unisom can be used to help with insomnia.
Both Unisom and Benadryl have diphenhydramine as an active ingredient in some of their formulations. However, the primary intention behind their marketing is different. Unisom aims to address sleeplessness, while Benadryl's primary purpose is to relieve allergy symptoms.
It's essential to note that while Unisom and Benadryl may have similar effects, they are not always interchangeable. Using Benadryl solely as a sleep aid might not be recommended, and it's crucial to understand the intended purpose and dosage of each medication.
Lastly, it's always advisable to consult with a healthcare professional before taking either Unisom or Benadryl. Since both medications can cause drowsiness, operating heavy machinery or driving after consumption might not be advisable.

Comparison Chart

Primary Usage

Sleep aid
Antihistamine for allergies

Active Ingredient

Doxylamine (in some formulations)

Side Effects

Drowsiness, dry mouth
Drowsiness, dry mouth, dizziness

Available Formulations

Tablets, softgels, liquid
Tablets, liquid, topical creams, gels

Recommended for Children

Not typically without consultation
Yes, with pediatric formulations

Unisom and Benadryl Definitions


A product containing doxylamine or diphenhydramine.
The pharmacist recommended Unisom with doxylamine for my sleep issue.


A brand-name medication for allergy relief.
When pollen season starts, I stock up on Benadryl.


A non-prescription drug for sleeplessness.
He buys Unisom whenever he's facing jet lag.


A drug commonly used for allergic reactions.
After the bee sting, he quickly took some Benadryl.


An over-the-counter medication for insomnia.
She uses Unisom occasionally to combat her sleepless nights.


An over-the-counter antihistamine.
I always carry Benadryl for my sudden allergy attacks.


A brand-name sleep aid.
I took Unisom last night and slept soundly.


A product containing diphenhydramine.
This itch relief cream has Benadryl in it.


A remedy often suggested for occasional sleep problems.
My doctor said I could try Unisom for those nights I can't drift off.


A remedy that can induce drowsiness.
I avoid taking Benadryl during the day because it makes me sleepy.


Antihistamine (trade name Benadryl) used to treat allergic reactions involving the nasal passages (hay fever) and also to treat motion sickness


What is the main ingredient in some Unisom products?

Doxylamine or diphenhydramine, depending on the formulation.

Can Benadryl help with sleep?

Yes, drowsiness is a side effect, so some people use it for sleep.

What is Benadryl primarily used for?

Benadryl is primarily used as an antihistamine for allergies.

Can children take Benadryl?

Yes, there are pediatric formulations of Benadryl.

What is Unisom primarily used for?

Unisom is primarily used as a sleep aid.

Can children take Unisom?

Only with a healthcare professional's advice.

Can I develop a tolerance to Benadryl if I take it regularly?

There is a potential for tolerance with frequent use, which may reduce its effectiveness. Consult a doctor for long-term use.

Can elderly individuals take Unisom or Benadryl?

Elderly individuals may be more sensitive to side effects. It's crucial to consult with a healthcare professional regarding appropriate dosages.

How long does the drowsy effect of Unisom typically last?

The drowsy effect of Unisom can last for several hours, and it's advised not to operate machinery or drive during this time.

Can I take Benadryl for a cold or cough?

Benadryl is primarily an antihistamine for allergies, but it may help with cold symptoms. Consult a healthcare professional for appropriate treatments.

Are there any common side effects of Unisom besides drowsiness?

Some common side effects include dry mouth, dizziness, and headache. Always refer to the product label or consult a pharmacist.

Can I take Unisom or Benadryl with alcohol?

Combining alcohol with either Unisom or Benadryl can intensify drowsiness and is not recommended.

Are there any known drug interactions with Unisom or Benadryl?

Yes, both medications can interact with other drugs. Always consult with a healthcare professional before starting a new medication.

Can I give my pet Benadryl for allergies?

While some veterinarians prescribe Benadryl for pets, always consult with them before giving any human medications to animals.

Can Unisom help with allergies?

No, Unisom is not marketed as an allergy medication.

Are there non-drowsy versions of Benadryl?

While some antihistamines offer non-drowsy versions, traditional Benadryl can cause drowsiness.

Are Unisom and Benadryl available over-the-counter?

Yes, both Unisom and Benadryl are available over-the-counter.

Is it safe to take Unisom and Benadryl together?

It's essential to consult with a healthcare professional before mixing medications.

Why might someone choose Unisom over Benadryl for sleep?

Unisom is specifically marketed and formulated as a sleep aid.

Can pregnant or breastfeeding women take Unisom or Benadryl?

It's essential to consult with a healthcare professional before taking any medication during pregnancy or breastfeeding.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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