Airway response to salbutamol and to ipratropium bromide after non-selective and cardioselective beta-blocker

Eight healthy men were randomly assigned in a latin square order to receive single doses of placebo, tertatolol 5 mg, propranolol 80 mg and atenolol 100 mg at 7-day intervals. Resting heart rate and pulmonary function were measured 10 min before and over the 240 min following dosing, and then 15 min after inhalation of salbutamol 200 micrograms and ipratropium bromide 40 micrograms. The three beta-blockers caused similar reductions in resting heart rate throughout the study, whereas placebo had no effect. The three beta-blockers, like placebo, produced no significant change in pulmonary function during the 240 min after dosing. The bronchodilator response to salbutamol after atenolol and placebo was preserved, whereas it was reduced after administration of either of the non-selective beta-blockers, tertatolol and propranolol. An unequivocal response of the airways to ipratropium bromide was observed after tertatolol and propranolol, which was much greater than after atenolol. No response was observed after placebo. Thus, despite bronchial beta 2-blockade, by non-selective beta-blockers, bronchodilatation was definitely produced by ipratropium bromide, confirming the predominant role of the parasympathetic system in the autonomic innervation of normal human airways.