NCIt definition : The hydrochloride salt form of naphazoline, an imidazole derivative and a direct-acting
sympathomimetic amine with vasoconstrictive properties. Upon ocular administration,
naphazoline hydrochloride exerts its effect by acting on alpha-adrenergic receptors
in the arterioles of the conjunctiva to produce vasoconstriction, resulting in decreased
conjunctival congestion and diminished itching, irritation and redness.;