title: Effect of salmeterol on seasonal changes in airway responsiveness and exhaled nitric oxide in pollen-sensitive asthmatic subjects.
abstract: OBJECTIVE
  Using a model of natural allergen exposure, we examined the effect of regular treatment with salmeterol on allergen-induced changes in airway responsiveness and exhaled nitric oxide (ENO).
  
  
  METHODS
  Double-blind, randomized, parallel-group study.
  
  
  METHODS
  Specialist allergy unit in a university hospital.
  
  
  METHODS
  Asthmatic patients sensitized to pollen allergens were randomly allocated to monotherapy with salmeterol (n = 14) or placebo (n = 13).
  
  
  METHODS
  Salmeterol, 25 micro g, and placebo inhalers, two puffs bid, for 6 weeks.
  
  
  METHODS
  Spirometry, the level of a provocative concentration of a substance (methacholine) causing a 20% fall in FEV(1) (PC(20)), the PC(20) level for adenosine 5'-monophosphate (AMP), and ENO were measured before the pollen season and were repeated at the height of the pollen season after 6 weeks of treatment with salmeterol or placebo.
  
  
  RESULTS
  The decrease in FEV(1) during the pollen season was significantly larger in the placebo group than in the salmeterol group, the mean difference in the change between the groups being 0.20 L (95% confidence interval, 0.03 to 0.35; p = 0.047). Changes in PC(20) for methacholine, PC(20) for AMP, and ENO levels were not significantly different between treatment groups. However, a mean (+/- SEM) decrease in the PC(20) for methacholine of -1.0 +/- 0.4 doubling concentrations was observed within the placebo group (p = 0.03), whereas no significant changes were observed within the salmeterol group. A significant decrease in PC(20) for AMP (doubling concentrations) was observed within the placebo group (-2.1 +/- 0.6; p = 0.003) and the salmeterol group (-1.5 +/- 0.4; p = 0.003). ENO concentrations increased significantly among the placebo and the salmeterol groups during natural pollen exposure.
  
  
  CONCLUSIONS
  These observations indicate that natural allergen exposure and the regular use of salmeterol are not associated with a greater increase in ENO and airway responsiveness than allergen exposure alone.
authors.affiliation: Sección de Alergología, Hospital Universitario Dr. Peset, Valencia, Spain. prieto_jes@gva.es
authors.forename: Luis
authors.initials: L
authors.lastname: Prieto
authors.forename: Valentina
authors.initials: V
authors.lastname: Gutiérrez
authors.forename: Vicente
authors.initials: V
authors.lastname: Torres
authors.forename: Sonia
authors.initials: S
authors.lastname: Uixera
authors.forename: Julio
authors.initials: J
authors.lastname: Marín
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D001944:Breath Tests; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000188:drug therapy*; D000068299:Salmeterol Xinafoate; D012621:Seasons
chemical_list: D009569:Nitric Oxide; D000249:Adenosine Monophosphate; D000068299:Salmeterol Xinafoate; D000420:Albuterol