Effect of inhaled menthol on citric acid induced cough in normal subjects.
BACKGROUND
Menthol is a commonly used ingredient in many over the counter cough remedies, but there is little objective evidence as to its efficacy.


METHODS
Twenty healthy subjects received a cough challenge consisting of five inhalations of 33 mumol citric acid from an air driven dosimeter. The challenge was repeated at hourly intervals for five hours. Five minutes before each challenge subjects inhaled, in a randomised design, either menthol 75% in eucalyptus oil or one of two placebos (pine oil or air).


RESULTS
Menthol inhalation caused a reduction in evoked cough when compared with either placebo.


CONCLUSIONS
Menthol is an effective antitussive agent in an evoked cough model.
Morice
A H
AH
University Department of Medicine and Pharmacology, Royal Hallamshire Hospital, Sheffield, UK.
Marshall
A E
AE
Higgins
K S
KS
Grattan
T J
TJ
D000280:Administration, Inhalation; D000328:Adult; D000996:Antitussive Agents / Q000008:administration & dosage*; D001985:Bronchial Provocation Tests; D002951:Citrates / Q000008:administration & dosage; D019343:Citric Acid; D003371:Cough / Q000139:chemically induced / Q000517:prevention & control*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008610:Menthol / Q000008:administration & dosage*; D008875:Middle Aged; D008954:Models, Biological; D011897:Random Allocation
D000996:Antitussive Agents; D002951:Citrates; D008610:Menthol; D019343:Citric Acid