Pseudoephedrine Hydrochloride is the hydrochloride salt form of pseudoephedrine, a phenethylamine and an diastereomer of ephedrine with sympathomimetic property. Pseudoephedrine hydrochloride displaces norepinephrine from storage vesicles in presynaptic neurones, thereby releasing norepinephrine into the neuronal synapses where it stimulates primarily alpha-adrenergic receptors. It also has weak direct agonist activity at alpha- and beta- adrenergic receptors. Receptor stimulation results in vasoconstriction and decreases nasal and sinus congestion. NCI Thesaurus (NCIt) A phenethylamine that is an isomer of EPHEDRINE which has less central nervous system effects and usage is mainly for respiratory tract decongestion. Medical Subject Headings (MeSH)