About Pseudoephedrine Alpha/Beta Adrenergic Agonist, a phenethylamine derivative, A nasal decongestant. Mechanism of Action of Pseudoephedrine It is a nasal decongestant with alpha-2 agonistic action. It produces local vasoconstriction, reduces blood flow, and causes shrinkage of mucosa which provides relief of nasal congestion. It reduces oedema of the nasal mucosa, thus improving ventilation, drainage and nasal stuffiness. About Triprolidine First generation histamine H1 antagonist, Alkylamine derivative, Antihistamine. Mechanism of Action of Triprolidine Triprolidine hydrochloride exerts it`s action by acting as an H1 receptor antagonist. It antagonizes most of the pharmacological actions of Histamine and reduces allergic symptoms. It also has anticholinergic properties and reduces secretions