Influence of Pindolol on Asthmatics and Effect of Bronchodilators

Abstract

Bronchospasm is a known side effect of the administration of β-blockers to asthmatics. The purpose of this study was to investigate (1) the frequency of bronchospasm caused by the administration of relatively low doses (2.5–7.5 mg) of pindolol, a β-blocker with intrinsic sympathetic activity (ISA) to asthmatics, (2) the severity of the bronchospasm and its reversibility and (3) 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 B A, 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 saibutamol was administered by a dosimetric aerosol (DA) at the usual dosage (200 µg) and the change in FEV₁ was observed at 60 min; thereafter 40 µg 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 (≧20% of baseline) was observed in 9 patients. Saibutamol did not have any effect on the decrease of FEV₁ 60 min after its administration, while IB brought FEV₁ back to its initial normal value 60 min later, in all except 1 patient. The only significant correlation between bronchial asthma characteristics and pindolol-induced bronchospasm was between airway hyperreactivity and bronchoconstriction

Are β-blockers ever safe in asthma?

“…4 Anecdotal case reports suggest that in special circumstances individual patients can be unaffected by the prescription of a β-blocker, 5 and a small group of 12 asthmatic patients given β-blockers for co-existing cardiac disease were reported to suffer no decline in respiratory function. 6 Many small volunteer studies of stable asthmatics (ranging from seven to 18 subjects) have shown measurable declines in respiratory function in response to propranolol, metoprolol and bisoprolol, pindolol, and atenolol, [7][8][9][10][11][12] although celiprolol, a cardioselective β-blocker with partial β2-agonist activity, appears to have little effect, [13][14][15] even in high dose. 16 Declines in respiratory function have also been documented following ophthalmic use of timolol, but not betaxolol.…”

Cardioselective Beta‐Blockers in Patients with Asthma and Concomitant Heart Failure or History of Myocardial Infarction: When Do Benefits Outweigh Risks?

“…Studies have shown that the anticholinergic bronchodilators ipratropium and oxitropium are effective in reversing noncardioselective beta-blocker-induced bronchospasm (71,72). However, several studies have found that short-acting inhaled beta 2 -agonists are effective in treating bronchoconstriction due to cardioselective beta-blockers (26,39,52).…”

Beta-Blockers after Myocardial Infarction: Do Benefits Ever Outweigh Risks in Asthma?

“…Giulekas et al [58]also found that the anticholinergic bronchodilator ipratropium was effective in reversing pindolol-induced bronchospasm, whereas albuterol did not. Other investigators have found that β 2 -agonists are not effective in reversing pindolol-induced bronchoconstriction [59, 60].…”