Meta-analysis may not be practicable for guiding antibiotic therapy.

b1-receptors are much more prevalent in the heart, while b2receptors are prevalent in bronchial smooth muscle [3]. The original evidence of adverse effects of b-blockers on airways was based on early case reports of acute bronchospasm associated with high doses of nonselective b-blockers [1]. Since then, cardioselective b-blockers have been developed that have .20 times the affinity for b1than b2-receptors and are therefore less likely to cause bronchospasm. It is valid to use cardioselective b-blockers in low-risk respiratory patients with high-risk cardiac conditions, but this should be done with close monitoring [4]. As cardioselective b-blockers are increasingly prescribed, it is not surprising that 67% of patients in our survey were using them. However, 33% of patients were taking nonselective b-blockers, which have not been shown to be safe in airways disease. Eight (30%) of the patients in our survey were on a b-blocker solely for hypertension, even though b-blockers are no longer regarded as first-line treatment for hypertension [5].