[The action of a tropic acid ester on bronchospasm: a double-blind study (author's transl)].

12 patients with chronic bronchitis were treated with two different doses (0.02 and 0.08 mg) of Sch 1000 (Atrovent) administered by metered dose inhalation and the results compared with those following administration of a placebo in a cross-over double-blind study. The airway resistance and thoracic gas volume fell significantly after treatment with the drug, with no appreciable difference in effect between the dosages. The bronchodilatory action of the drug lasted about 4 hours and differed markedly from that of the placebo. No anticholinergic side effects or specific effects on the circulation were encountered at the administered dosage.