Oxymetazoline

Oxymetazoline binds to α1- and α2-adrenoceptors, which are Gq- and Gi-protein-coupled receptors respectively. α1-adrenoceptors agonism promotes vascular smooth muscle contraction by increasing intracellular calcium levels through activating phospholipase C, while α2-adrenoceptors agonism, specifically the α2B-adrenoceptors, can also elicit vasoconstriction through the inhibition of adenyl cyclase.

Rosacea is a condition characterized by transient and persistent facial erythema. By stimulating α1A-adrenoceptors and causing vasoconstriction, oxymetazoline is believed to diminish the symptoms of erythema. In blepharoptosis, it is hypothesized that oxymetazoline works by stimulating α-adrenergic receptors on the Müller muscle that elevates the upper eyelid, causing muscle contraction. Oxymetazoline is used in combination with tetracaine for local anesthesia in dentistry. Such combination use adds beneficial effects: the vasoconstrictor counteracts the local anesthetic agent's vasodilatory action, thereby constricting dilated arterioles and reducing blood flow to the application area. Oxymetazoline relieves nasal congestion by vasoconstricting the respiratory microvasculature, in both resistance and capacitance blood vessels on the human nasal mucosa, leading to decreased nasal mucosal blood flow, edema, and airflow resistance.