What does "diphenhydramine" mean?

An antihistamine and anticholinergic drug that blocks the effect of histamine at H₁ receptor sites, relieving allergy symptoms. It also reduces smooth muscle contraction, increases heart rate, and sedates the user by blocking muscarinic acetylcholine receptors (mAChRs).

What is a synonym for "diphenhydramine"?

Common synonyms include: benadryl, zzzquil.

How do you pronounce "diphenhydramine"?

Pronounced //ˌdʌɪ.fɛnˈhʌɪ.dɹəm.iːn//.

Diphenhydramine

//ˌdʌɪ.fɛnˈhʌɪ.dɹəm.iːn// noun

noun ·Rare ·Advanced level

Definitions

Noun

1
An antihistamine and anticholinergic drug that blocks the effect of histamine at H₁ receptor sites, relieving allergy symptoms. It also reduces smooth muscle contraction, increases heart rate, and sedates the user by blocking muscarinic acetylcholine receptors (mAChRs). countable, uncountable
"Diphenhydramine is a convenient and cheap antihistamine for use, but there are other drugs that do not make the user tired."
2
antihistamine (trade name Benadryl) used to treat allergic reactions involving the nasal passages (hay fever) and also to treat motion sickness wordnet

Synonyms

All synonyms

benadryl zzzquil

Example

More examples

"Diphenhydramine is a convenient and cheap antihistamine for use, but there are other drugs that do not make the user tired."

Etymology

From diphen(yl) + (benz)hydr(yl) + -amine.

Related phrases

smooth muscle

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.