Caffeine (30mg) + Chlorpheniramine Maleate (4mg) + Paracetamol (500mg) + Phenylephrine (10mg) (Medical Monograph)

Overview

A fixed-dose combination (FDC) medication primarily used for the symptomatic relief of common cold, allergic rhinitis, and sinusitis. It combines an analgesic-antipyretic (Paracetamol), a first-generation antihistamine (Chlorpheniramine), a nasal decongestant (Phenylephrine), and a mild CNS stimulant (Caffeine). This combination addresses multiple symptoms simultaneously, including fever, pain, nasal congestion, sneezing, and rhinorrhea. The inclusion of caffeine is intended to counteract the sedative effects of chlorpheniramine and potentially enhance the analgesic effect of paracetamol.

This combination works synergistically on different pathways: Paracetamol inhibits central cyclooxygenase (COX), particularly the COX-2 variant, and modulates the endogenous cannabinoid system, reducing pain and fever. Chlorpheniramine competitively antagonizes histamine at the H1 receptor, reducing allergic symptoms like sneezing and rhinorrhea. Phenylephrine is a selective alpha-1 adrenergic receptor agonist, causing vasoconstriction in the nasal mucosa, reducing edema and congestion. Caffeine is a non-selective adenosine receptor antagonist, which can reduce drowsiness caused by chlorpheniramine and may have a mild adjuvant analgesic effect.