Neither atenolol nor celiprolol affected daily asthma control and inhaler use in our study. Four conditions of the study need to be borne in mind: (1) the dose and duration of beta-blockers used; (2) the small number of subjects studied; (3) the mild nature of their asthma; and (4) the absence of events such as chest infections which might have had more severe consequences in those on beta-blockers. In a previous study of subjects with mild asthma treated with 100 mg atenolol, only small clinically insignificant bron-choconstrictive changes were found. Judging by their low medication requirements (five required only intermittent treatment and three required a beta-2 agonist inhaler alone), as well as symptom scores and spirometry, most subjects in our study had only mild asthma. However, it is not known what would have happened to respiratory function if these subjects with asthma had been exposed to some asthma trigger factors other than withdrawal of beta-2 stimulation, for example, upper respiratory tract infection. more

In conclusion, we showed that a single-dose challenge with celiprolol is not followed by bronchocon-striction in untreated asthmatic subjects. Nevertheless, as a rule, beta-blockade of any form should not be given to hypertensive asthmatic subjects and should only be considered after treatment with other antihypertensive agents, such as calcium antagonists and angiotensin-converting enzyme inhibitors, have proved unsatisfactory. If the use of a beta-blocker is unavoidable, a cardioselective agent or labetalol should be used.

Our study, like that of Dorow, suggests that celiprolol may provide a greater margin of safety than does atenolol, which hitherto has been favored in this setting. An important proviso is that the patient must be maintained on bronchodilator therapy and particular care should be given to the patients during any intercurrent infection. It must be stressed that the results of both the current and previous studies must be viewed as preliminary and that the safety and efficacy of celiprolol need to be confirmed in larger studies of longer duration including varying doses of the drug and in patients with more severe degrees of asthma.