Chlorpheniramine Maleate (4mg) + Codeine (10mg) + Menthol (1.5mg/5ml) (Medical Monograph)

Overview

A fixed-dose combination antitussive and antihistaminic syrup used for the symptomatic relief of dry, non-productive cough associated with allergic conditions like allergic rhinitis or the common cold. Chlorpheniramine is a first-generation alkylamine H1-antihistamine, Codeine is a centrally-acting opioid antitussive, and Menthol provides local soothing and decongestant effects.

The combination acts synergistically. Chlorpheniramine antagonizes histamine at H1 receptors, reducing allergic symptoms and providing mild sedative effects. Codeine, an opioid agonist, suppresses the cough reflex by direct action on the cough center in the medulla oblongata. Menthol acts as a topical cooling/soothing agent on irritated pharyngeal mucosa, providing symptomatic relief and a sensation of easier breathing.