Description

Dextromethorphan 

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.

Phenylephrine hydrobromide

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.

Chlorpheniramine maleate

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

Menthol

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.