title: Effect of a single dose of montelukast sodium on methacholine chloride PC20.
abstract: BACKGROUND
  It is currently recommended that leukotriene modifiers (receptor antagonists and synthesis inhibitors) be withheld for a minimum of 24 h before direct bronchoprovocation testing, but there is little evidence to support this recommendation.
  
  
  OBJECTIVE
  To examine the effect of a single oral dose of montelukast sodium 10 mg on airway response to methacholine chloride-induced bronchoconstriction.
  
  
  METHODS
  A double-blind, placebo-controlled, randomized crossover trial was performed in 12 subjects with asthma whose methacholine chloride concentration causing a 20% decrease in the forced expiratory volume during the first second of exhalation (PC20) was 8 mg/mL or lower and a baseline forced expiratory volume during the first second of exhalation of 70% predicted or greater. Two-minute tidal breathing methacholine chloride inhalation challenges were performed 1 h and 25 h after both 10 mg montelukast sodium and identical-appearing placebo.
  
  
  RESULTS
  There were no significant differences in the methacholine chloride PC20 between active treatment and placebo at 1 h post-10 mg montelukast sodium (1.0 mg/mL versus 1.3 mg/mL; n=12; P=0.17, respectively) or at 25 h post-10 mg montelukast sodium (1.4 mg/mL versus 1.9 mg/mL; n=11; P=0.15, respectively).
  
  
  CONCLUSIONS
  A single dose of montelukast sodium did not affect methacholine chloride-induced bronchoconstriction measured after 1 h and 25 h.
authors.affiliation: University of Saskatchewan, Royal University Hospital, Saskatoon, Canada.
authors.forename: Beth E
authors.initials: BE
authors.lastname: Davis
authors.forename: Donald W
authors.initials: DW
authors.lastname: Cockcroft
mesh_terms: D000085:Acetates / Q000008:administration & dosage*; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy*; D001985:Bronchial Provocation Tests; D018592:Cross-Over Studies; D003521:Cyclopropanes; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D011336:Probability; D011804:Quinolines / Q000008:administration & dosage*; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013440:Sulfides
chemical_list: D000085:Acetates; D018927:Anti-Asthmatic Agents; D003521:Cyclopropanes; D011804:Quinolines; D013440:Sulfides; D016210:Methacholine Chloride; C093875:montelukast