[Onset of action and maximum effect of bronchodilators administered by a metered dose inhaler. Clinical investigations with fenoterol, hexoprenaline, ipratropium bromide, isoprenaline, orciprenaline, salbutamol and terbutaline (author's transl)].

The acute effect of bronchodilatory metered dose inhalers was tested by whole-body plethysmography in patients with chronic obstructive airway disease. All patients had already used metered dose inhalers. The 18 patients of group A were successfully using the parasympatholytic drug ipratropium bromide. The onset of action of hexoprenaline, salbutamol and terbutaline was slightly quicker than that of ipratropium bromide but the maximum bronchodilation was similar. The 18 patients of group B considered adrenergics to be much more effective. Mean values showed that the onset of bronchodilation and maximum effect with fenoterol, isoprenaline, and orciprenaline was quicker and stronger than after ipratropium bromide over the first 20 minutes. Following ipratropium bromide the single resistance diagrams of group B, with the exception of 4 patients, showed bronchodilation equal to that of group A and also to that obtained following adrenergics in group B. The patients apparently judged bronchodilation on the basis of the adrenergic side effects rather than by improvement of dyspnoea. There were 3 patients, however, who repeatedly showed better bronchodilation in response to adrenergics than parasympholytic agents, not depending of the way of application.