Terfenadine in exercise induced asthma

Abstract

Terfenadine given orally in a single dose of 120 mg and 180 mg offered significant protection against exercise induced asthma in the patients studied, whereas 60 mg of terfenadine showed no significant inhibition. Terfenadine is a potent antagonist of histamine H1 receptor mediated responses both in vitro and in vivo and does not possess anticholinergic, antiserotonin, or antiadrenergic properties. It antagonises histamine in two ways: by competitive blockade at low concentrations and by a non-equilibrium blockade at higher concentrations. The inhibitory effect of terfenadine in this study is consistent with observations reported with the inhaled antihistamine clemastine in exercise induced asthma. Obviously more detailed experimental and clinical studies will be required before terfenadine can be recommended for management of asthmatic patients.