[Ipratropium bromide in controlled clinical trials. Short communication (II): Time-response measurements of pulmonary function after ipratropium bromide and isoprenaline]

Abstract

(8R)-3alpha-Hydroxy-8-isopropyl-1alphaH, 5alphaH, 5alphaH-tropaniumbromide (+/-)-tropate (ipratropiumbromide, Sch 1000, Atrovent) was compared with isoprenaline in a cross-over study with randomized selection in 12 stable asthmatics, using total airways resistance (Rt) measured by whole-body plethysmography, peak expiratory flow (PEF) and pulse rate as parameters. 2 puffs ipratropiumbromide (0.02 mg per puff) or isoprenaline (0.1 mg per puff) were administered by metered dose inhaler and measurements taken at 5, 20, 35, 50, 90 min, 2, 3, 4, and 6 h later. Drugs were given on alternate days. Rt decreased significantly (p less than 0.001) for 4 h to 53% of the initial value after ipratropiumbromide and to 70% of the initial value after isoprenaline, but only for about 2 h after the latter. The maximum 20-min effect on Rt was almost the same for both drugs. The difference in the time course of the bronchodilation was also significant. The rise in PEF after 4 h following ipratropiumbromide was similarly highly significant (p less than 0.001); as for Rt the time course for both drugs ran nearly parallel. Neither substance caused a significant rise in pulse rate at the dosages used.