Cardio-selective and non-selective beta-blockers in chronic obstructive pulmonary disease: effects on bronchodilator...

Patients with chronic obstructive pulmonary disease (COPD) often have co-existing cardiovascular disease and may require beta-blocker treatment. There are limited data on the effects of beta-blockers on the response to inhaled beta2-agonists and exercise capacity in patients with COPD.

To determine the effects of different doses of cardio-selective and non-selective beta-blockers on the acute bronchodilator response to beta-agonists in COPD, and to assess their effects on exercise capacity.

A double-blind, randomized, three-way cross-over (metoprolol 95 mg, propranolol 80 mg, placebo) study with a final open-label high-dose arm (metoprolol 190 mg). After 1 week of each treatment, the bronchodilator response to salbutamol was measured after first inducing bronchoconstriction using methacholine. Exercise capacity was assessed using the incremental shuttle walk test.

Eleven patients with moderate COPD were recruited. Treatments were well-tolerated although two did not participate in the high-dose metoprolol phase. The area under the salbutamol-response curve was lower after propranolol compared with placebo (P=0.0006). The area under the curve also tended to be lower after high-dose metoprolol (P=0.076). The per cent recovery of the methacholine-induced fall was also lower after high-dose metoprolol (P=0.0018). Low-dose metoprolol did not alter the bronchodilator response. Oxygen saturation at peak exercise was lower with all beta-blocker treatments (P=0.046).

Non-selective beta-blockers and high doses of cardio-selective beta-blockers may inhibit the bronchodilator response to beta2-agonists in patients with COPD. Beta-blockers were also associated with lower oxygen saturation during exercise. The clinical significance of these adverse effects is uncertain in view of the benefits of beta-blocker treatment for cardiovascular disease.