Salmeterol: a four week study of a long-acting beta-adrenoceptor agonist for the treatment of reversible airways disease.

A total of 1,068 patients, aged 18-70 yrs, with mild to moderate reversible airways disease, were recruited into a multicentre, double-blind, parallel group study in 76 European centres. Following a 2 week run-in period, the 692 patients fulfilling the entry criteria were randomized to 4 weeks treatment with either salmeterol 12.5, 50 or 100 micrograms or placebo b.d. all given by pressurized inhaler, with assessments of symptoms and ventilatory lung function prior to dosing. All three doses of salmeterol had significant efficacy, manifested by increased morning and evening peak expiratory flow rate (PEFR) (by 35-59 l.min-1 and 11-38 l.min-1, respectively), by reduced diurnal variation in PEFR, and by reduced requirement for additional bronchodilator for symptomatic relief. These effects were dose-related. Daytime asthma symptoms and nocturnal awakenings were significantly reduced by salmeterol treatment, although these reductions were not dose-related. The incidence of adverse events was low. Pharmacologically predictable events (e.g. tremor) were more frequent after treatment with 100 micrograms b.d. than with placebo. On the basis of the efficacy and side-effect information, 50 micrograms b.d. is considered to be the optimum dose for the treatment of this group of asthmatics.