Drug class – Antitussives
- Dextromethorphan has been demonstrated to significantly suppress acute cough; highly significant reduction in cough counts with the dose of 30 mg dextromethorphan.
- Found to be superior in the capsaicin challenge model; has a relatively slow onset of action peaking in efficacy after ∼2 hours.
- Has a prolonged antitussive activity, being significantly better than placebo after as long as 24 hours.
Drug class – Nasal decongestant
- A selective alpha-1 adrenergic receptor agonist used primarily as a decongestant in symptoms associated with cold.
- Its effectiveness stems from its vasoconstriction of nasal blood vessels leading to decreased mucosal edema.
Drug class – Antihistamines
- Chlorpheniramine maleate is a first-generation antihistaminic that antagonizes histamine H1-receptor.
- It is specifically a potent inverse agonist of the histamine H1 receptor
- It is mainly used as an anti-allergic but has some anti-depressant and anti-anxiety actions, with unknown mechanism as well
Drug class – Counterirritant
- Menthol is a monoterpene produced by the peppermint plant Mentha arvens.
- Menthol’s cooling activity is through the specific ‘cold’ receptor TRPM8, a member of the transient receptor potential family of nociceptors, primarily located on afferent sensory neurons.
- Evidence indicates that the antitussive activity of menthol may reside in the activation of nasal as opposed to lung sensory afferents.