Proxymetacaine

An article about the local anesthetic Proxymetacaine

Proxymetacaine

Chemical structure of Proxymetacaine

Proxymetacaine, also known as proparacaine, is a topical local anesthetic commonly used in ophthalmology and optometry. It is primarily used to numb the surface of the eye for various procedures, including tonometry, gonioscopy, and removal of foreign bodies.

Pharmacology

Proxymetacaine works by blocking the sodium channels in the neuronal cell membrane, which inhibits the initiation and conduction of nerve impulses. This action results in a temporary loss of sensation in the area where the drug is applied.

Mechanism of Action

Proxymetacaine is an ester of para-aminobenzoic acid (PABA) and acts by stabilizing the neuronal membrane. By preventing the influx of sodium ions, it effectively blocks the generation and transmission of nerve impulses, leading to localized anesthesia.

Duration of Action

The onset of anesthesia with proxymetacaine is rapid, typically occurring within 30 seconds of application. The duration of action is relatively short, lasting approximately 10 to 20 minutes, which is suitable for short diagnostic and therapeutic procedures.

Clinical Use

Proxymetacaine is used in various clinical settings:

• Tonometry: To measure intraocular pressure.
• Gonioscopy: To examine the anterior chamber angle of the eye.
• Foreign body removal: To facilitate the removal of foreign objects from the corneal surface.
• Cataract surgery: As a preoperative anesthetic.

Side Effects

While proxymetacaine is generally well-tolerated, some patients may experience side effects such as:

• Mild stinging or burning sensation upon application.
• Temporary blurred vision.
• Rarely, allergic reactions or corneal damage with prolonged use.

Precautions

Proxymetacaine should be used with caution in patients with known hypersensitivity to local anesthetics. Prolonged use or overuse can lead to corneal damage and should be avoided.

Related pages

• Local anesthetic
• Ophthalmology
• Optometry