Oxitropium bromide, a new anticholinergic drug, in a dose-response and placebo comparison in obstructive airway...

12 patients with obstructive airway diseases took part in a double-blind study in which 0.02 and 0.2 mg of Ba 253 as metered aerosols were compared with a placebo. Both doses of Ba 253 elicited a significant fall of mean total airway resistance compared to the placebo, and this fall was still discernible even 8 h after inhalation. Under the higher dose, the maximum response was significantly greater and it occurred about 2 h after inhalation; the response was still significantly more pronounced 8 h after inhalation. There was no objective evidence of local or systemic side effects attributable to a vagus-blocking effect. In the light of published reports and our own experience, when Ba 253 is inhaled in the stated doses it appears to be equivalent to ipratropium bromide as regards potency, duration of action, tolerance and therapeutic safety margin.