Inhaled Salmeterol and Salbutamol in Asthmatic Patients

SUMMARY Salmeterol (SM) Is a new 13,-adrenoceptor agonist for Inhaled use that has been shown to produce long-lasting bronchodllatlon In asthmatic patients. In the present study, evaluating effi­ cacy and possible development of tachyphylaxis after SM, 12patients with stable asthma were in­ cluded after the demonstration of reversibility In FEV1 of at least 15% to 200 I1gsalbutamol (S8) or 20% to 500 I1g S8. At Inclusion all patlenta were receiving treatment with Inhaled ~2-agonlsta, and 11 of the 12 patients were also receiving Inhaled corticosteroids. The patients were treated for two 2-wk periods with eitherInhaled SM 50 I1gtwice a day or S8 200 I1gfour times a day, following a double-blind, double-dummy, randomized design. The treatment parlods were separated by a washout period of 1 wk. Dose-response curves to Inhaled S8 were obtained the day before and the day after each treatment parlod. On each of these days, basel FEY" tremor, heart rate, and blood pressure were recorded and were then followed after the Inhalation of 100 + 300 + 900 I1gS8 to obtain a cumulative dose-response curve. During the treatment periods, as well as during the washout week after each treatment, the patients recorded their morning and evening peak expiratory flow (PEF) each day before the Inhalation of the study drug. Subjective asthma aymptoms were moni­ tored by a visual analog scale aftereach treatment period. The dose-responsecurves to S8 revealed no signs of a reduced response to S8 after any of the treatments, but significant Increases In basal FEV, and FVC were seen after the SM period (p < 0.05). The PEF values were also significantly higher, both In the morning (p < 0.001) and the evening (p < 0.01), during the SM period compared with that during the S8 period. The morning PEF during the week after the SM period was signifi­ cantly higher (p < 0.05) compared with the week after the S8 treatment. The patients' VAS-score showed a significantly better night's sleep and a lower degree of dyspnea during the SM period (p < 0.05). Of the 12 patients, 10 preferred SM and two had no preference. The use of rescue S8 Inhalations was about 50% lower during the SM period (p < 0.05). We conclude that Inhaled SM 50 I1gtwice a day produces a better control of asthma symptoms than does S8 200 I-Ig four times a day. There was no evidence of an Increased risk for tachyphylaxis In the pulmonary response to ~2-stlmulatlon with the more long-acting SM. However, It should be considered that 11 of 12 pa­ tients were receiving treatment also with Inhaled sterolds,";"hlch may heve prevented the develop­