Does Benadryl make you sleepy?

Benadryl (diphenhydramine) is a first‑generation antihistamine commonly used for allergy relief, motion sickness, and as a sleep aid. Its sedating effect occurs because diphenhydramine crosses into the brain and blocks histamine receptors, leading to drowsiness. Avoid combining it with other sedating drugs or alcohol, and do not drive or operate machinery until you know how it affects you.

How much Benadryl makes you drowsy?

A typical dose of 25–50 mg can induce sleepiness, with effects lasting up to 8 hours. Individual response varies by weight, age, and metabolism.

What is Benadryl used for?

• Allergic rhinitis: sneezing, runny nose, itchy/watery eyes, scratchy throat
• Skin itching (oral or topical): insect bites, sunburn, minor irritations, poison ivy/oak, hives
• Sleep aid
• Motion sickness prevention/treatment

Common side effects

• Drowsiness
• Dizziness
• Dry mouth
• Constipation
• Lack of coordination
• Headache

Rare serious effects:

• Urinary retention
• Confusion or memory issues
• Blurred vision

Who should avoid Benadryl?

Avoid or use with caution if you have:

• Narrow‑angle glaucoma
• Enlarged prostate or bladder obstruction
• Asthma or COPD
• Liver disease
• Low blood pressure
• Pregnancy or breastfeeding without provider approval

Non‑sedating antihistamine alternatives

Second‑generation oral antihistamines less likely to cause drowsiness:

• Zyrtec (cetirizine)
• Claritin (loratadine)
• Allegra (fexofenadine)
• Xyzal (levocetirizine)
• Clarinex (desloratadine)

Nasal spray option (minimal drowsiness):

• Astepro Allergy (azelastine)

Antihistamine eye drops:

• Zaditor/Alaway (ketotifen)
• Pataday (olopatadine)
• Optivar (azelastine)

Sources

• Diphenhydramine hydrochloride – Prescribers’ Digital Reference. Accessed Mar 13, 2025.
• Sicari V, Zabbo CP. Diphenhydramine. StatPearls. Updated 2023 Jul 10; Accessed Mar 13, 2025.