title: The effect of inhaled menthol on upper airway resistance in humans: a randomized controlled crossover study.
abstract: BACKGROUND
  Menthol (l-menthol) is a naturally-occurring cold receptor agonist commonly used to provide symptomatic relief for upper airway congestion. Menthol can also reduce the sensation of dyspnea. It is unclear whether the physiological action of menthol in dyspnea reduction is through its cold receptor agonist effect or whether associated mechanical changes occur in the upper airway.
  
  
  OBJECTIVE
  To determine whether menthol inhalation alters upper airway resistance in humans.
  
  
  METHODS
  A randomized, sham-controlled, single-blinded crossover study of inhaled menthol on upper airway resistance during semirecumbent quiet breathing in healthy subjects was conducted. Ten healthy participants (eight female) with a mean (± SD) age of 21±1.6 years completed the study.
  
  
  RESULTS
  Nasal resistance before testing was similar on both occasions. No differences were found in respiratory frequency (mean ± SEM) (menthol 17.0±1.1 cmH2O⁄L⁄s; sham 16.9±0.9 cmH2O⁄L⁄s), minute ventilation (menthol 7.7±0.5 cmH2O⁄L⁄s; sham 7.9±0.5 cmH2O⁄L⁄s) or total inspiratory time⁄total breath time (menthol 0.4±0.1 cmH2O⁄L⁄s; sham 0.4±0.1 cmH2O⁄L⁄s). The upper airway resistance was similar during menthol (3.47±0.32 cmH2O⁄L⁄s) and sham (3.27±0.28 cmH2O⁄L⁄s) (P=0.33) inhalation.
  
  
  CONCLUSIONS
  Inhalation of menthol does not alter upper airway resistance in awake human subjects.
authors: Sleep Disorders Laboratory, Kingston General Hospital and Department of Medicine, Queen's University, Kingston, Ontario, Canada.
authors: Effie Justin
authors: EJ
authors: Pereira
authors: Lauren
authors: L
authors: Sim
authors: Helen
authors: H
authors: Driver
authors: Christopher
authors: C
authors: Parker
authors: Michael
authors: M
authors: Fitzpatrick
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000403:Airway Resistance / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008610:Menthol / Q000008:administration & dosage / Q000494:pharmacology*; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D008610:Menthol