Influence of pindolol on asthmatics and effect of bronchodilators

Bronchospasm is a known side effect of the administration of beta-blockers to asthmatics. The purpose of this study was to investigate the frequency of bronchospasm caused by the administration of relatively low doses (2.5-7.5 mg) of pindolol, a beta-blocker with intrinsic sympathetic activity (ISA) to asthmatics, the severity of the bronchospasm and its reversibility and the probable correlations of bronchial asthma (BA) characteristics (severity, duration, allergy and airway hyperreactivity) with existing or nonexisting bronchospasm. Seventeen asthmatic patients: 10 men and 7 women, with a mean age of 44 +/- 10 years, participated in this study. The duration and severity of BA, the presence of allergy determined by skin tests and the bronchial hyperreactivity to methacholine inhalation challenge were observed on the first day of study. On the following days, the respiratory function parameters forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), and the pulse rate were measured before and 30, 60 and 90 min after the administration of placebo and pindolol. Then salbutamol was administered by a dosimetric aerosol (DA) at the usual dosage (200 micrograms) and the change in FEV1 was observed at 60 min; thereafter 40 micrograms of ipratropium bromide (IB) were administered by DA and FEV1 was measured after 60 min. Pindolol was administered gradually by mouth (2.5 mg every 30 min), the maximal total dose being 7.5 mg. Administration of pindolol caused a significant fall of FEV1 of 12 +/- 11% compared to placebo. A significant total decrease of FEV1 (greater than or equal to 20% of baseline) was observed in 9 patients.(ABSTRACT TRUNCATED AT 250 WORDS)