Overview Pseudoephedrine is a widely used oral decongestant that relieves nasal and sinus congestion caused by colds, allergies, and sinus infections. It is a common ingredient in many over-the-counter and prescription medications. Due to its stimulant-like effects, pseudoephedrine is regulated in many countries to prevent misuse. What is Pseudoephedrine? Pseudoephedrine is a sympathomimetic amine that primarily works by narrowing blood vessels in the nasal passages, reducing swelling and congestion. It is commonly found in cold and allergy medications, either as a standalone ingredient or combined with antihistamines and pain relievers. How It Works Pseudoephedrine stimulates alpha-adrenergic receptors, causing vasoconstriction (narrowing…