Tetryzoline, also known as tetrahydrozoline, is a derivative of imidazoline, is found in over-the-counter eye drops and nasal sprays. Other derivatives include naphazoline, oxymetazoline, and xylometazoline. Tetrahydrozoline is an alpha agonist and its main mechanism of action is the constriction of conjunctival blood vessels. This serves to relieve the redness of the eye caused by minor ocular irritants. To treat allergic conjunctivitis, tetryzoline can be combined in a solution with antazoline.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.