What is the purpose of an antihistamine?

The purpose of an antihistamine is to block the effects of histamine, a substance that the body produces during an allergic reaction. Histamines can cause symptoms such as itching, sneezing, runny nose, and other allergic reactions. Antihistamines work by binding to histamine receptors, preventing histamine from exerting its effects, and thus alleviating these symptoms. This action makes them an essential part of treating allergy-related conditions, providing relief to individuals suffering from allergies.

The other options describe functions that are addressed by other types of medications. For instance, cough relief is typically managed by antitussives or expectorants, while asthma is controlled by bronchodilators and corticosteroids. Facilitating mucus expulsion is generally the role of expectorants, which help thin mucus to make it easier to cough up. Therefore, antihistamines specifically target the issue of histamine during allergic reactions, making this understanding central to their role in medication administration.