decongestant

A decongestant is a medication intended to relieve nasal congestion by reducing swelling of the nasal mucosa. Decongestants achieve this primarily through constriction of blood vessels in the nasal passages, which decreases edema and improves airflow. They are used to provide temporary relief from congestion associated with infections, allergies, and some sinus conditions.

Most decongestants are either systemic (oral) agents such as pseudoephedrine and phenylephrine or topical (intranasal) sprays containing oxymetazoline, xylometazoline, or naphazoline. Systemic agents act on adrenergic receptors throughout the body, while intranasal sprays exert a more local effect on the nasal mucosa.

Onset and duration vary by preparation. Oral decongestants typically begin within 30–60 minutes and last for several hours; topical intranasal decongestants act within minutes and can relieve symptoms for about 4–12 hours, depending on the product and formulation.

Common adverse effects include tachycardia, elevated blood pressure, insomnia, nervousness, and urinary retention, particularly in people with prostatic hypertrophy or hypertension. A notable risk with topical formulations is rebound congestion (rhinitis medicamentosa) after prolonged use, making symptoms worse when the drug is stopped. Use is cautioned in hypertension, ischemic heart disease, arrhythmias, glaucoma, and thyroid disorders.

Pseudoephedrine is subject to regulatory controls in many countries due to concerns about misuse. Phenylephrine is widely available but its clinical benefit is debated. Intranasal corticosteroids and saline rinses provide alternative relief without vasoconstriction, especially for chronic congestion from allergies or rhinitis.