15 Sep

Effect of Long-term Salmeterol Therapy Compared With As-Needed Albuterol Use on Airway Hyperresponsiveness: Discussion

Effect of Long-term Salmeterol Therapy Compared With As-Needed Albuterol Use on Airway Hyperresponsiveness: DiscussionThis study has shown that regular, long-term use of salmeterol aerosol, 42 ^g twice daily, in patients with asthma results in sustained improvements in pulmonary function and symptom control with no evidence of an increase in bronchial hyperresponsiveness during or following treatment. The treatment groups were similar with respect to the number of patients having asthma exacerbations during both treatment and posttreatment, and no evidence suggested that the severity of exacerbations was different between groups. Most exacerbations were treated either in a physician’s office or at home with few patients requiring treatment in the emergency department or resulting in hospitalization.
Methacholine challenges performed 10 to 14 h postdosing showed a modest protective effect for salmeterol of approximately one doubling dose of methacholine after 4, 12, and 24 weeks of treatment. These results are similar to previous results showing protection against methacholine-induced broncho-constriction of 0.6 to 1.2 doubling doses approximately 12 h postdosing over an 8-week treatment period. Similarly, in a single-dose study, protection against methacholine-induced bronchoconstriction of approximately 1.5 doubling doses was shown 12 h after a 50-^g dose of salmeterol. natural asthma treatment

In this study, the twice-daily (morning and evening) dosing schedule as stated in the prescription labeling for salmeterol was maintained with no interruption. This was done to mimic the standard conditions for use of salmeterol. Bronchial responsiveness was assessed at the end of the dosing period when any development of underlying hyperresponsiveness would be most apparent. It is evident from previous studies that the maximal or near-maximal bronchoprotective effects of salmeterol obtained initially 1 h postdose are reduced with regular use. In these studies, reduced protection of approximately 1 to 2 doubling doses of methacholine was observed 4 to 8 weeks after the first dose of salme-terol. However, a loss of protection was not observed in all patients, possibly because of polymorphisms of the human β2-receptor gene that are associated with alterations in β2-receptor function. In addition, a plateau in effect appeared between 4 and 8 weeks. Because these studies were conducted over < 8 weeks, the protective effects of salmeterol were not studied over a long-term treatment period. In the current study, a 24-week treatment period was used to demonstrate that regular, long-term salmeterol use does not lead to a progressive loss of broncho-protection from that seen following 4 weeks of therapy.

Categories: Airway
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