title: Attenuation of hyperventilation-induced bronchospasm by terfenadine: a new antihistamine.
abstract: The effect of terfenadine, a selective H1-receptor antagonist devoid of central nervous system side effects, was evaluated on hyperventilation-induced bronchospasm in 11 adult subjects with asthma in a double-blind, placebo-controlled, crossover study. Increases in specific airway resistance (SRaw) were induced by isocapnic hyperventilation with dry air on two occasions, 7 days apart. Before the tests, the subjects received oral terfenadine (120 mg, twice daily) or placebo for 3 days with the last dose administered 3 hours before the test. Baseline SRaw and spirometric values (vital capacity and FEV1) were similar for the two tests. Terfenadine yielded a significant (p less than 0.001) parallel shift to the right of the stimulus (hyperventilation)-response (SRaw) curve; 100% increases in SRaw occurred at ventilation rates of 44 L/min after placebo treatment and 64 L/min after terfenadine treatment. These data suggest that histamine release plays a role in hyperventilation-induced bronchospasm despite the fact that increase in plasma histamine has not been found in this situation, in contrast to exercise-induced bronchospasm.
mesh_terms: D000293:Adolescent; D000328:Adult; D001250:Asthma, Exercise-Induced / Q000188:drug therapy; D001559:Benzhydryl Compounds / Q000627:therapeutic use*; D001986:Bronchial Spasm / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006636:Histamine Release / Q000187:drug effects; D006801:Humans; D006985:Hyperventilation / Q000150:complications* / Q000503:physiopathology; D008297:Male; D016593:Terfenadine
chemical_list: D001559:Benzhydryl Compounds; D006634:Histamine H1 Antagonists; D016593:Terfenadine