H1 receptor antagonists

H1 receptor antagonists, also known as antihistamines, are medications that block the effects of histamine at H1 receptors in the body. Histamine is a chemical involved in allergic reactions, causing symptoms like sneezing, itching, runny nose, and watery eyes. By preventing histamine from binding to these receptors, H1 antagonists help reduce allergy symptoms. They are commonly used to treat allergies, hay fever, hives, and other allergic conditions. Some are available over-the-counter, while others require a prescription. They vary in how long they last and how sedating they might be.