The Antitussive Effects of Menthol, Camphor and Cineole in Conscious Guinea-pigs

✍ Scribed by E.A. Laude; A.H. Morice; T.J. Grattan

• Publisher: Elsevier
• Year: 1994
• Tongue: English
• Weight: 306 KB
• Volume: 7
• Category: Article
• ISSN: 0952-0600
• DOI: 10.1006/pulp.1994.1021

✦ Synopsis

SUMMARY: Menthol and other aromatic vapours have been widely used in the symptomatic treatment of upper respiratory tract infections, although there is little objective evidence as to their benefit. We have investigated the action of aromatic vapours on the cough reflex in conscious guinea-pigs. Animals ((n=13)) were pretreated with air or test vapours for (5 \mathrm{~min}) at a rate of (1 / / \mathrm{min}). One minute later the animal was challenged with aerosolized citric acid for (2 \mathrm{~min}). Control responses to air pretreatment were not significantly different throughout the procedures. Three concentrations of each aromatic vapour were used ( 3,10 and (30 \mu \mathrm{g} / \mathrm{l}) menthol, 50,133 and (500 \mu \mathrm{g} / /) camphor and (0.8,2.7) and (8 \mathrm{mg} / \mathrm{l}) cineole). Menthol proved the most effective antitussive- 10 and (30 \mu \mathrm{g} / \mathrm{l}) produced a significant 28 and (56 %) reduction in cough frequency- (-500 \mu \mathrm{g} / \mathrm{I}) camphor gave a significant (33 %) reduction, while cineole, at the concentrations used, had no significant effect. An increase in cough latency coincided with a reduction in cough frequency. These results demonstrate the efficacy of aromatic vapours as antitussives in chemically induced cough.