What are antihistamines ? Give an example.

Explanation

The hypersensitivity of some persons towards certain drugs (penicillin, sulpha drugs), dust, pollen grains, cat fur, a particular food or fabric, etc. is called allergy. Allergy is caused by release of a substance called histamine in the body Antihistamines are drugs which either reduce or inhibit the action of histamine in the body thereby preventing allergy. Two important antihistamine or anti-allergic drugs are brompheniramine and terfenadine.
Mode of action. Histamines interact with the binding sites of receptor in the body to produce allergy. Antihistamines compete with histamines for these binding sites of receptor and thus do not allow histamine to produce allergy. Thus, antihistamines are drugs which interfere with the natural action of histamine by competing for histamine binding sites of receptor.