Terfenadine is an antihistamine medication that is used to treat allergies, hay fever, chronic hives, and other allergic reactions. It works by blocking the action of histamine, a substance produced by the body during an allergic reaction. It can also be used to prevent motion sickness. Common side effects include dry mouth, nausea, dizziness, and drowsiness.
Terfenadine was an antihistamine medication that was previously used to treat allergic rhinitis (hay fever) and other allergic conditions . It was marketed under various brand names, including Seldane in the United States, Triludan in the United Kingdom, and Teldane in Australia. However, it was withdrawn from the market in the 1990s due to the risk of causing a serious heart rhythm problem called QT interval prolongation.
Terfenadine is a prodrug, which means that it is inactive until it is metabolized by the liver into its active metabolite, fexofenadine. Fexofenadine is a selective histamine H1 receptor antagonist, which means that it blocks the action of histamine, a substance that is released by the body during an allergic reaction. Histamine causes symptoms such as sneezing, runny nose, itchy eyes, and hives.
Terfenadine was withdrawn from the market because it was found to interact with certain other medications, which could increase the levels of terfenadine in the blood and increase the risk of QT interval prolongation. QT interval prolongation can lead to a serious heart rhythm problem called torsades de pointes, which can be fatal.
Fexofenadine, the active metabolite of terfenadine, is now available as a prescription and over-the-counter medication. Fexofenadine is not associated with the same risks of QT interval prolongation as terfenadine.