Source:http://linkedlifedata.com/resource/umls/id/C0148485
NCI: The hydrochloride salt form of tetrahydrozoline, an imidazole derivative with sympathomimetic property. Applied locally to the eye or nose, tetrahydrozoline binds to and activates alpha-adrenergic receptors, resulting in vasoconstriction and decreased nasal and ophthalmic congestion.