Terfenadine

Absorption

On the basis of a mass balance study using 14C labeled terfenadine the oral absorption of terfenadine was estimated to be at least 70%

Toxicity

Mild (e.g., headache, nausea, confusion), but adverse cardiac events including cardiac arrest, ventricular arrhythmias including torsades de pointes and QT prolongation have been reported. LD50=mg/kg (orally in mice)

The Uses of Terfenadine

Terfenadine has been used to study the role of histamine in itch related to proteinase-activated receptors (PARs) in mice. Terfenadine has also been used to block histamine receptor type 1 to study the pathogenesis of 2,4-dinitrobenzene sulfonic acid (DNBS)-induced ulcerative colitis in rats.

Background

In the U.S., Terfenadine was superseded by fexofenadine in the 1990s due to the risk of cardiac arrhythmia caused by QT interval prolongation.

Indications

For the treatment of allergic rhinitis, hay fever, and allergic skin disorders.

What are the applications of Application

Terfenadine is a histamine H1-receptor antagonist, which blocks HERG and KIR6 channels

Pharmacokinetics

Terfenadine, an H1-receptor antagonist antihistamine, is similar in structure to astemizole and haloperidol, a butyrophenone antipsychotic. The active metabolite of terfenadine is fexofenadine.

Metabolism

Hepatic