title: The effects of an inhaled beta(2)-adrenergic agonist on lower esophageal function: a dose-response study.
abstract: OBJECTIVE
  Albuterol, a beta(2)-adrenergic agonist that is commonly used to treat asthma, reduces bronchial smooth muscle tone. The pharmacodynamics of inhaled albuterol on esophageal function were studied in healthy volunteers.
  
  
  METHODS
  A prospective, randomized, placebo-controlled, double-blind crossover design.
  
  
  METHODS
  An academic medical center.
  
  
  METHODS
  Nine healthy volunteers (five men, four women; age, 22 to 30 years).
  
  
  METHODS
  Albuterol (2.5 to 10 mg) or placebo was given via nebulizer. Volunteers were studied at two sessions, 1 week apart, using a 6-cm manometry assembly and a low-compliance pneumohydraulic pump. The percentage of lower esophageal sphincter (LES) relaxation, the frequency of transient LES relaxations (TLESRs), and the amplitude, duration, and propagation velocity of esophageal contractions were measured at 5 and 10 cm above the LES. Dependent measures were evaluated using two-way, repeated-measures analysis of variance.
  
  
  RESULTS
  Albuterol therapy reduced LES basal tone in a dose-dependent manner (baseline, 17.0 +/- 2.6 mm Hg; at 10 mg, 8.9 +/- 2.1 mm Hg; p = 0.01). The frequency of TLESRs was not different from placebo (not significant). Albuterol reduced the amplitude of esophageal contractions at 5 cm above the LES (baseline, 72.5 +/- 18.6 mm Hg; at 10 mg, 48.8 +/- 10.0 mm Hg; p<0.05). A significant reduction in esophageal body contractile amplitudes was noted at 10 cm (F[1,6] = 7.05; p<0.05).
  
  
  CONCLUSIONS
  Inhaled albuterol reduced LES basal tone and contractile amplitudes in the smooth muscle esophageal body in a dose-dependent manner. Inhaled beta(2)-agonists may increase the likelihood of acid reflux in a subset of patients who receive cumulative dosing.
authors.affiliation: Marvin M. Schuster Center for Digestive and Motility Disorders, the Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Crowell
authors.forename: E N
authors.initials: EN
authors.lastname: Zayat
authors.forename: B E
authors.initials: BE
authors.lastname: Lacy
authors.forename: A
authors.initials: A
authors.lastname: Schettler-Duncan
authors.forename: M C
authors.initials: MC
authors.lastname: Liu
mesh_terms: D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D000420:Albuterol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004943:Esophagogastric Junction / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D011446:Prospective Studies
chemical_list: D000318:Adrenergic beta-Agonists; D000420:Albuterol