A medication that blocks the effects of histamine, a substance produced by the body that causes symptoms such as itching, sneezing, and runny nose.
The word "antihistamine" is derived from the prefix "anti-" meaning "against" and the noun "histamine", meaning "a substance that is released by the body in response to injury and in various allergic and inflammatory conditions and causes dilatation of the small blood vessels, the constriction of smooth muscle, and increased permeability of capillaries.".
- I took an antihistamine to relieve my hay fever symptoms.
- The doctor prescribed me an antihistamine for my allergic reaction.
- Antihistamines are commonly used to treat symptoms of allergies, such as sneezing and runny nose.
- The antihistamine helped to reduce the redness and itching caused by the mosquito bites.
- Many cold and flu medications contain antihistamines to help relieve symptoms such as a runny nose.