The reason is that deaths have occurred from its use when it has been taken together with some other drugs or in people with a particular group of heart problems. In the USA, terfenadine is mainly known as Seldane . In Britain, terfenadine is available only on prescription by a doctor. Until recently it was available without prescription, but this has been stopped because of the safety problem. Terfenadine is an antihistamine .
Antihistamines are medicines which help against allergies.
See the previous section for its other names . Antihistamines help against allergies by blocking the action of histamine , a chemical released in the body during allergic reactions. The antihistamines we had before terfenadine are still used by many people. These older antihistamines may make you sleepy. But even if they don't, they make you a worse driver and interfere with mental function.