What is the use of tetracaine for eye anesthesia?

From the Guidelines

Tetracaine is an effective topical anesthetic used for eye procedures, and its use is recommended for ocular anesthesia in specific situations, as outlined in the most recent guidelines 1. The use of tetracaine for eye anesthesia is a common practice, particularly for brief diagnostic procedures, foreign body removal, or before minor eye surgeries.

• Tetracaine is typically available as 0.5% eye drops, and for ocular anesthesia, 1-2 drops are instilled into the conjunctival sac 2-3 minutes before the procedure.
• The anesthetic effects of tetracaine begin within 30 seconds and last 15-20 minutes, with additional drops applied if needed, but not exceeding 5-7 drops per session.
• Tetracaine works by blocking sodium channels in nerve membranes, preventing the generation and conduction of nerve impulses, as described in the guidelines for monitoring and management of pediatric patients before, during, and after sedation for diagnostic and therapeutic procedures 1.
• The application of a topical local anesthetic, such as tetracaine, is necessary prior to certain ocular procedures, as stated in the guidelines for the management of Stevens-Johnson syndrome/toxic epidermal necrolysis in adults 1.
• Patients should be advised not to touch or rub the eye while anesthetized to avoid corneal damage, and should not use contact lenses until the effect has completely worn off.
• Side effects of tetracaine may include temporary burning or stinging upon application, and prolonged use can lead to corneal epithelial toxicity, delayed healing, and increased risk of infection.
• The maximum recommended dose of tetracaine is 1.5 mg/kg with epinephrine, and 1 mg/kg without epinephrine, as outlined in the guidelines for monitoring and management of pediatric patients before, during, and after sedation for diagnostic and therapeutic procedures 1.

From the FDA Drug Label

Tetracaine Hydrochloride Ophthalmic Solution 0.5% is an ester local anesthetic indicated for procedures requiring a rapid and short-acting topical ophthalmic anesthetic. Topical administration of tetracainehydrochloride ophthalmic solution results in localized temporary anesthesia.

The use of tetracaine for eye anesthesia is for procedures requiring a rapid and short-acting topical ophthalmic anesthetic. It provides localized temporary anesthesia with a maximum effect achieved within 10–20 seconds after instillation, and efficacy lasting 10–20 minutes 2, 2.

• Key benefits: rapid onset, short-acting
• Administration: one drop topically in the eye(s) as needed 2

From the Research

Use of Tetracaine for Eye Anesthesia

• Tetracaine is a topical anesthetic commonly used in ophthalmology for procedures such as intravitreal injections and cataract surgery 3, 4, 5, 6, 7.
• The drug is used to numb the eye, reducing pain and discomfort during medical procedures 3, 4, 5, 6, 7.
• Tetracaine has been shown to be effective in providing corneal anesthesia, with a longer duration of action compared to other anesthetics such as proparacaine and lidocaine 5.
• However, tetracaine can cause ocular side effects such as conjunctival hyperemia and chemosis, although these are typically mild and transient 5.
• The use of tetracaine as a topical anesthetic has been compared to other anesthetics, including proparacaine, lidocaine, and cocaine, with varying results 3, 4, 5, 6, 7.

Comparison with Other Anesthetics

• Tetracaine has been shown to have a lower toxicity profile compared to other anesthetics such as bupivacaine and lidocaine 4.
• In a study comparing the corneal endothelial toxicity of topical anesthetic agents, tetracaine was found to be statistically indistinguishable from balanced salt solution, although mild toxicity was evident clinically 4.
• Tetracaine has also been compared to proparacaine and lidocaine in terms of its antimicrobial activity, with results showing that all three anesthetics have some level of antimicrobial activity 6.

Clinical Applications

• Tetracaine is commonly used in clinical settings for procedures such as intravitreal injections and cataract surgery 3, 4, 5, 6, 7.
• The use of tetracaine as a topical anesthetic has been shown to be effective in reducing pain and discomfort during these procedures 7.
• However, the choice of anesthetic technique may depend on individual patient needs and preferences, as well as the specific procedure being performed 7.