| Indication | For the treatment of nasal congestion, sinus congestion, Eustachian tube congestion, and vasomotor rhinitis, and as an adjunct to other agents in the optimum treatment of allergic rhinitis, croup, sinusitis, otitis media, and tracheobronchitis. Also used as first-line therapy of priapism. |
| Pharmacodynamics | Pseudoephedrine is a sympathomimetic agent, structurally similar to ephedrine, used to relieve nasal and sinus congestion and reduce air-travel-related otalgia in adults. 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. Unlike antihistamines, which modify the systemic histamine-mediated allergic response, pseudoephedrine only serves to relieve nasal congestion commonly associated with colds or allergies. The advantage of oral pseudoephedrine over topical nasal preparations, such as oxymetazoline, is that it does not cause rebound congestion (rhinitis medicamentosa). |
| Mechanism of action | Pseudoephedrine acts directly on both alpha- and, to a lesser degree, beta-adrenergic receptors. Through direct action on alpha-adrenergic receptors in the mucosa of the respiratory tract, pseudoephedrine produces vasoconstriction. Pseudoephedrine relaxes bronchial smooth muscle by stimulating beta2-adrenergic receptors. 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. |
| Absorption | Pseudoephedrine is readily and almost completely absorbed from the GI tract and there is no evidence of first-pass metabolism. |
| Volume of distribution | Not Available |
| Protein binding | Pseudoephedrine does not bind to human plasma proteins over the concentration range of 50 to 2000 ng/mL |
| Metabolism | Hepatic. |
| Route of elimination | Not Available |
| Half life | 9-16 hours |
| Clearance | Not Available |
| Toxicity | Common adverse reactions include nervousness, restlessness, and insomnia. Rare adverse reactions include difficult/painful urination, dizziness/lightheadedness, heart palpitations, headache, increased sweating, nausea/vomiting, trembling, troubled breathing, unusual paleness, and weakness. |
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