Salmeterol provides prolonged protection against exercise-induced bronchoconstriction in a majority of subjects with mild, stable asthma.
In patients with asthma, exercise-induced symptoms are well recognized and frequently limiting. Currently available beta 2-receptor agonists have a short duration of action and breakthrough symptoms may occur. We studied the efficacy of the recently developed long acting inhaled beta 2-agonist salmeterol with respect to protection against exercise-induced bronchoconstriction. Twelve patients with mild to moderate, stable asthma were recruited (age range 21-33 years). They each underwent treadmill exercise tests, with target heart rate of approximately 90% of predicted maximum, 1, 6 and 12 h after a single dose of salmeterol 50 micrograms, salbutamol 200 micrograms and placebo. Patients breathed through a two-way valve, inspiring dry air from a compressed air cylinder via a Douglas bag to maintain constant humidity. The primary efficacy variable analysed was the maximum percentage fall in FEV1 and FVC from pre-exercise readings within the first 30 min post-exercise. At 1 h post-dose there was significant protection in terms of fall in mean +/- SEM FEV1 in response to exercise challenge after either salmeterol (0.83 +/- 6.2%) or salbutamol (3.8 +/- 5.5%) as compared with placebo (27.1 +/- 7.3%). At 6 h post-dose, fall in FEV1 on salmeterol was 11.3 +/- 3.8% as compared with salbutamol, 28.0 +/- 5.7% and placebo, 32.0 +/- 7.0%. At 12 h post-dosing there was still significant protection in terms of fall in FEV1 in the salmeterol treated group, 12.8 +/- 4.9%, as compared with salbutamol, 28.7 +/- 4.9% and placebo, 25.4 +/- 7.3%.(ABSTRACT TRUNCATED AT 250 WORDS)
Newnham
D M
DM
Department of Respiratory Medicine, King's Cross Hospital, Dundee, U.K.
Ingram
C G
CG
Earnshaw
J
J
Palmer
J B
JB
Dhillon
D P
DP
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D000420:Albuterol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D001250:Asthma, Exercise-Induced / Q000188:drug therapy*; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D000068299:Salmeterol Xinafoate; D014797:Vital Capacity / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D000068299:Salmeterol Xinafoate; D000420:Albuterol