<p>Pseudoephedrine is both an &alpha;-and &beta;-adrenergic receptor agonist. It causes vasoconstriction via direct stimulation of &alpha;-adrenergic receptors of the respiratory mucosa. It also directly stimulates &beta;-adrenergic receptors causing bronchial relaxation, increased heart rate and contractility.<br />
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Like ephedrine, pseudoephedrine releasing norepinephrine from its storage sites, an indirect effect. This is its main and direct mechanism of action. The displaced noradrenaline is released into the neuronal synapse where it is free to activate the postsynaptic adrenergic receptors.</p>