About Oxymetazoline Alpha Adrenergic Agonist, Imidazoline Derivative, Vasoconstrictor (nasal decongestant). Mechanism of Action of Oxymetazoline It is a nasal decongestant with selective alpha-2 agonistic action. It produces local vasoconstriction, reduces blood flow, and causes shrinkage of mucosa which provides relief of nasal congestion Side Effects of Oxymetazoline 1. Dryness of nose and throat 2. Irritation 3. Burning sensation 4. Stinging 5. Sneezing 6. Rebound congestion 7. Hypertension