Exercise-induced bronchoconstriction in patients with bronchial asthma. Its prevention with an antihistaminic agent.

14 asthmatic patients developing regularly exercise-induced bronchoconstriction were subjected to a submaximal exercise on a bicycle ergometer. On the first day the exercise was not preceded by any medication; on the second, 50 mg thiazinamium was given, and on the third day 2 mg atropine was given before the exercise. The changes in the calibre of the bronchi were assessed with a Wright peak flow meter. With thiazinamium a complete protection against the bronchoconstriction was observed in 12 patients, in one the protection was partial and in an other no beneficial effect of the drug was found. It seems that protection given by thiazinamium was due to its antihistaminic property and not to the anticholinergic one, as among 10 patients protected by thiazinamium, only 2 were also protected by the atropine.