antihistamine
noun
an·ti·his·ta·mine
ˌan-tē-ˈhi-stə-ˌmēn 
-mən,
ˌan-tī-
: any of various compounds that counteract histamine in the body and that are used for treating allergic reactions (such as hay fever) and cold symptoms
antihistamine
adjective
Examples of antihistamine in a Sentence
Recent Examples on the Web
These include some cholesterol-lowering statins, blood pressure medications, and antihistamines.
—
Zia Sherrell, Health, 7 Feb. 2026
However, first-generation antihistamines can also cause drowsiness, sedation, and fatigue, which can affect alertness, concentration, and memory.
—Karen Berger, Verywell Health, 5 Feb. 2026
Investigators found medications, including an antidepressant and antihistamine drugs, in Monique’s system at the time of her death.
—Sarah Rumpf-Whitten , Adam Sabes, FOXNews.com, 3 Feb. 2026
Hives that don’t improve with antihistamines or are accompanied by swelling, trouble breathing, or other signs of an allergic reaction.
—Alex Vance, Parents, 29 Jan. 2026
See All Example Sentences for antihistamine
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Zia Sherrell, Health, 7 Feb. 2026
However, first-generation antihistamines can also cause drowsiness, sedation, and fatigue, which can affect alertness, concentration, and memory.
—Karen Berger, Verywell Health, 5 Feb. 2026
Investigators found medications, including an antidepressant and antihistamine drugs, in Monique’s system at the time of her death.
—Sarah Rumpf-Whitten , Adam Sabes, FOXNews.com, 3 Feb. 2026
Hives that don’t improve with antihistamines or are accompanied by swelling, trouble breathing, or other signs of an allergic reaction.
—Alex Vance, Parents, 29 Jan. 2026
See All Example Sentences for antihistamine
Cite this Entry
“Antihistamine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antihistamine. Accessed 14 Feb. 2026.
Copy CitationKids Definition
antihistamine
noun
an·ti·his·ta·mine
ˌant-i-ˈhis-tə-ˌmēn
-mən,
ˌan-ˌtī-
: any of various drugs used for treating allergic reactions and cold symptoms
Medical Definition
antihistamine
1 of 2 adjective
an·ti·his·ta·mine
ˌant-i-ˈhis-tə-ˌmēn, ˌan-ˌtī-, -mən
: tending to block or counteract the physiological action of histamine
human blood lacks antihistamine activity
antihistamine
2 of 2 noun
: any of various compounds that oppose the actions of histamine and are used especially for treating allergic reactions (as hay fever), cold symptoms, and motion sickness
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