Nnc 38 1049

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A histamine antagonist is an agent that inhibits release (e.g., Cromolyn) or action (Diphenhydramine) of histamine. H1 antihistamines are used as treatment for symptoms of allergies such as runny nose. Allergies are caused by an excessive type 1 hypersensitivity response of the body to allergens, such as pollen released by plants. An allergic reaction, which if severe enough can lead to anaphylaxis, results in excessive release of histamines and other mediators by the body. Other uses of H1 antihistamines help with symptoms of local inflammation that results from various conditions, such as insect stings, even if there is no allergic reaction. Other commonly used examples of antihistamines include the H2 antagonists (Cimetidine) which are widely used for the treatment of acid reflux and stomach ulcers as they decrease gastric acid production.