Effects of beta-adrenoceptors blocking eye drops in patients with chronic bronchitis.

Beta-blocker eyedrops used on asthmatic patients are known to enhance asthma which is, as chronic bronchitis, an obstructive disease of the lung, and an authentic bronchoconstriction is always possible. A single blind parallel trial in 3 groups of 10 patients with grade II and III chronic bronchitis, was conducted to evaluate the cardiovascular and bronchial tolerance of 3 beta-blocker eyedrops: timolol, betaxolol and carteolol compared to placebo. The following parameters were measured during a 90 minutes period: heart rate, systolic and diastolic blood pressure, forced expiratory volume in one second, vital capacity. It appeared that only heart rate lowers significantly under the influence of the beta-blocker eyedrop, the other parameters did not change and no difference was noticed between the three eyedrops. However, comparison of individual values showed a significant decrease of forced expiratory volume in one second in certain subjects and this, although betaxolol is a beta 1 selective beta-blocker. Caution should be taken each time beta-blocker eyedrops are prescribed for glaucoma to patients with chronic bronchitis.