A fixed-dose combination of a first-generation alkylamine antihistamine (Chlorpheniramine Maleate) and a non-opioid antitussive (Dextromethorphan Hydrobromide). It is primarily indicated for the symptomatic relief of dry, non-productive cough associated with allergic conditions like the common cold, allergic rhinitis, and upper respiratory tract infections. Chlorpheniramine provides anti-allergic and anti-inflammatory effects, while Dextromethorphan acts centrally to suppress the cough reflex.
Adult Dosage: One tablet (Chlorpheniramine Maleate 2mg + Dextromethorphan HBr 10mg) every 4-6 hours. Maximum: 4 tablets in 24 hours.
Instructions: Administer orally with or without food. Take with a full glass of water. Do not crush or chew unless specified (some brands are chewable). Avoid taking at bedtime if sedation is undesirable, but for nocturnal cough, bedtime dose is common.
Chlorpheniramine Maleate competitively antagonizes histamine at the H1 receptor, inhibiting the physiological effects of histamine (vasodilation, increased capillary permeability, bronchoconstriction). Dextromethorphan Hydrobromide acts centrally on the cough center in the medulla oblongata, raising the threshold for coughing. It is a non-competitive antagonist of the NMDA receptor and an agonist of sigma-1 receptors, which contributes to its cough suppressant and other pharmacological effects.