Does inhaling menthol affect nasal patency or cough?

Area of Science:

• Pediatric Respiratory Medicine
• Pharmacology
• Sensory Science

Background:

• Menthol is widely used in over-the-counter (OTC) medications.
• Limited data exists on menthol's beneficial effects, particularly in children.
• Understanding menthol's impact on nasal function is crucial for its common use.

Purpose of the Study:

• To evaluate the effect of menthol inhalation on nasal airflow, perceived nasal patency, and cough reflex in healthy children.
• To provide evidence-based insights into the efficacy of menthol in OTC products.

Main Methods:

• A single-blind, pseudo-randomized cross-over trial was conducted with 42 healthy children (aged 10-11).
• Participants inhaled either menthol or a eucalyptus oil placebo on consecutive days.
• Nasal airflow (spirometry), perceived nasal patency (visual analogue scale - VAS), and cough response to citric acid were measured.

Main Results:

• Menthol inhalation showed no significant impact on objective spirometric measurements of nasal airflow.
• A significant increase in the perception of nasal patency was observed after menthol inhalation (mean difference in log VAS: -0.207).
• While menthol reduced cough counts compared to baseline, the difference was not statistically significant compared to placebo.

Conclusions:

• Menthol enhances the subjective perception of nasal patency but does not objectively improve nasal airflow in healthy school-aged children.
• Findings may not be generalizable to younger children or those with rhinitis.
• Further studies on efficacy and safety in diverse pediatric populations are warranted.