Proxymetacaine or proparacaine (USAN

United States Adopted Name

United States Adopted Names are unique nonproprietary names assigned to pharmaceuticals marketed in the United States. Each name is assigned by the USAN Council, which is co-sponsored by the American Medical Association , the United States Pharmacopeial Convention , and the American Pharmacists...

) is a topical anesthetic

Topical anesthetic

A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area. Topical anesthetics are available in creams,...

 drug of the aminoester group.

Indications and usage

Proxymetacaine hydrochloride ophthalmic solution (eye drop

Eye drop

Eye drops are saline-containing drops used as a route to administer medication in the eye. Depending on the condition being treated, they may contain steroids, antihistamines, sympathomimetics, beta receptor blockers, parasympathomimetics, parasympatholytics, prostaglandins, non-steroidal...

s) is indicated for procedures such as tonometry

Tonometry

Tonometry is the procedure eye care professionals perform to determine the intraocular pressure , the fluid pressure inside the eye. It is an important test in the evaluation of patients at risk from glaucoma...

, gonioscopy

Gonioscopy

Gonioscopy describes the use of a goniolens in conjunction with a slit lamp or operating microscope to gain a view of the iridocorneal angle, or the anatomical angle formed between the eye's cornea and iris...

, removal of foreign bodies

Foreign body

A foreign body is any object originating outside the body. In machinery, it can mean any unwanted intruding object.Most references to foreign bodies involve propulsion through natural orifices into hollow organs....

, or other similar procedures requiring topical anesthesia of the cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

 and conjunctiva

Conjunctiva

The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...

.

Warnings

Proxymetacaine is for topical ophthalmic use only, and it is specifically not intended for injection. Prolonged use of this or any other topical ocular anesthetic may produce permanent corneal opacification with accompanying visual loss

Vision loss

Vision loss or visual loss is the absence of vision where it existed before, which can happen either acutely or chronically .-Ranges of vision loss:...

.

Mechanism of action

Proxymetacaine is believed to act as an antagonist

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

 on voltage-gated sodium channels to affect the permeability of neuronal membranes; how this inhibits pain sensations and the exact mechanism of action of proxymetacaine are, however, unknown.

How supplied

Proxymetacaine is available as its hydrochloride salt in ophthalmic solutions at a concentration of 0.5%. Although it is no longer on patent, it is still marketed under the trade name

Trade name

A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....

s Alcaine, Ak-Taine, and others.