Pseudoephedrine

Pseudoephedrine is a sympathomimetic amine commonly used as a decongestant. The salts pseudoephedrine hydrochloride and pseudoephedrine sulfate are found in many over-the-counter preparations either as single-ingredient preparations, or more commonly in combination with antihistamines and/or paracetamol/ibuprofen.

Mode of action

Pseudoephedrine is a sympathomimetic amine - that is, its principal mechanism of action relies on its indirect action on the adrenergic receptor system. Whilst it may have weak agonist activity at α- and β-adrenergic receptors, the principal mechanism is to displace noradrenaline from storage vesicles in presynaptic neurons. The displaced noradrenaline is released into the neuronal synapse where it is free to activate the aforementioned postsynaptic adrenergic receptors.

Related Topics:
Sympathomimetic - Amine - Adrenergic receptor - Agonist - Noradrenaline - Vesicles - Presynaptic - Neurons - Synapse - Postsynaptic

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The vasoconstriction that pseudoephedrine produces is believed to be principally an α-adrenergic receptor response. Whilst all sympathomimetic amines, to some extent, have decongestant action; pseudoephedrine shows greater selectivity for the nasal mucosa and a lower affinity for central nervous system (CNS) adrenergic-receptors than other sympathomimetic amines. (+)-(1S,2S)-pseudoephedrine shows far lower CNS activity than other Ephedra alkaloids, ephedrine, and (-)-(1R,2R)-pseudoephedrine.

Related Topics:
Vasoconstriction - Central nervous system - Alkaloid - Ephedrine

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