To the Editors:
Historically, the use of β-adrenergic blockers in patients with airways disease has been discouraged. However, recent meta-analyses suggest that cardioselective β-blockers are safe in people with mild-to-moderate airways disease 1, 2. We have identified patients with chest disease on β-agonist bronchodilators, who were simultaneously taking β-blocker drugs. We have also looked at the reasons for co-prescription of these “competing” drugs and whether cardioselective β-blockers were being used.
Over 2 yrs (2005–2006) in a district general hospital, C.D. Shee prospectively recorded the names of patients he saw who were concomitantly taking β-blockers and β2-agonists. Patients were encountered in outpatient clinics, as hospital in-patients and as referrals (consults). The data were analysed retrospectively. A total of 34 patients were identified and hospital notes were found for 27 (18 males, mean (range) age 69 (54–88) yrs). It seemed that the co-prescription of these drugs was often inadvertent. In no instance did the hospital notes nor the general practitioners’ letter specifically mention why two competing drug classes were being used simultaneously. It was not always clear whether it was a general practitioner (family doctor) or a hospital doctor who had originally instigated specific drugs.
Of the patients using β-agonists, 19 had diagnoses of chronic obstructive airways disease and eight had asthma. A total of 21 (78%) subjects were taking salbutamol via a metered-dose inhaler, four (15%) were taking nebulised salbutamol and two (7%) were taking a long-acting bronchodilator. Cardioselective β-blockers were being taken by 18 (67%) subjects (atenolol n = 14, bisoprolol n = 3, metoprolol n = 1) and nine (33%) subjects were taking nonselective β-blockers (carvedilol n = 3, sotalol n = 2, propanolol n = 2, oxprenolol n = 1, carvedilol with sotalol n = 1). Eight (30%) subjects were taking β-blockers primarily for heart failure, eight (30%) for isolated hypertension and five (19%) for hypertension with ischaemic heart disease. Other indications were for angina (two subjects), atrial fibrillation (one subject), migraine (one subject), hyperthyroidism (one subject) and unclear (one subject).
In a separate study, on a 1-day in-patient survey (November 21, 2006), drug charts were analysed for 198 patients identified on eight medical wards. Of these, 32 (16%) subjects were taking β-agonists and 27 (14%) subjects were taking β-blockers. Only one (0.5%) patient was taking both.
β1-receptors are much more prevalent in the heart, while β2-receptors are prevalent in bronchial smooth muscle 3. The original evidence of adverse effects of β-blockers on airways was based on early case reports of acute bronchospasm associated with high doses of nonselective β-blockers 1. Since then, cardioselective β-blockers have been developed that have >20 times the affinity for β1- than β2-receptors and are therefore less likely to cause bronchospasm. It is valid to use cardioselective β-blockers in low-risk respiratory patients with high-risk cardiac conditions, but this should be done with close monitoring 4. As cardioselective β-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 β-blockers, which have not been shown to be safe in airways disease. Eight (30%) of the patients in our survey were on a β-blocker solely for hypertension, even though β-blockers are no longer regarded as first-line treatment for hypertension 5.
Concomitant use of β-agonist and β-blocker drugs does not appear to be common. The in-patient point prevalence was 0.5% and over a 2-yr period, in a variety of settings, we encountered only 34 examples (27 analysed). Our survey suggests that co-prescription of these drugs may often be inadvertent and that in some patients with airways disease, β-blockers could be stopped or a cardioselective β1-antagonist substituted.
Statement of interest
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