Dextromethorphan Hydrobromide (10mg) + Menthol (1.5mg) + Cetirizine (2mg) + Phenylpropanolamine (12mg) (Medical Monograph)

Overview

A fixed-dose combination (FDC) medication primarily indicated for the symptomatic relief of cough and cold. It combines a centrally-acting antitussive (Dextromethorphan), a nasal decongestant (Phenylpropanolamine), a second-generation antihistamine (Cetirizine), and a topical soothing agent (Menthol). This combination targets multiple symptoms of upper respiratory tract infections (URTI) and allergic rhinitis, providing relief from dry cough, nasal congestion, rhinorrhea, and sneezing. It is widely used in the Indian OTC market for acute, self-limiting conditions.

The combination works synergistically on different pathways of the cough reflex and cold symptoms. Dextromethorphan suppresses the cough center in the medulla oblongata. Phenylpropanolamine causes vasoconstriction in the nasal mucosa via alpha-1 adrenergic receptors, reducing edema and congestion. Cetirizine competitively inhibits histamine at H1-receptors, reducing allergic symptoms like sneezing and rhinorrhea. Menthol activates cold-sensitive TRPM8 receptors in the respiratory tract, providing a cooling sensation and mild local anesthetic effect that can soothe throat irritation.