What is the use of Proparacaine (a local anesthetic)?

From the Guidelines

Proparacaine should be used with caution and under medical supervision due to its potential to cause systemic absorption and allergic reactions, and its contraindication in patients with hypersensitivity to ester-type anesthetics. The medication is typically administered as 0.5% eye drops and provides rapid onset of action within 20 seconds, lasting approximately 15 minutes 1. The standard dosage is 1-2 drops in the affected eye before procedures like tonometry, removal of foreign bodies, or suture removal. Some key points to consider when using proparacaine include:

• It should only be used under medical supervision and never prescribed for home use, as repeated application can delay healing, mask worsening conditions, and potentially damage the corneal epithelium.
• Side effects include temporary stinging upon application, blurred vision, and potential allergic reactions.
• The medication works by blocking sodium channels in nerve membranes, preventing the generation and conduction of nerve impulses that transmit pain signals.
• Proparacaine is contraindicated in patients with hypersensitivity to ester-type anesthetics and should be used cautiously in those with cardiac conditions due to potential systemic absorption 1. In terms of specific guidelines, the use of proparacaine is recommended in certain situations, such as:
• For brief numbing of the eye surface before procedures like tonometry, removal of foreign bodies, or suture removal.
• In combination with other forms of local anesthesia for larger or more complex cutaneous procedures. However, it is essential to follow the recommended dosage and administration guidelines to minimize the risk of adverse effects. Overall, proparacaine can be a useful medication for numbing the eye surface, but its use should be carefully considered and monitored by a medical professional to ensure safe and effective treatment.

From the FDA Drug Label

INDICATIONS AND USAGE: Proparacaine hydrochloride ophthalmic solution is indicated for topical anesthesia in ophthalmic practice. CLINICAL PHARMACOLOGY: Proparacaine is a rapid acting local anesthetic suitable for ophthalmic use. The main use of Proparacaine is for topical anesthesia in ophthalmic practice 2, and it acts as a rapid acting local anesthetic 2.

• Key uses include:
  • Measurement of intraocular pressure (tonometry)
  • Removal of foreign bodies and sutures from the cornea
  • Conjunctival scraping in diagnosis
  • Gonioscopic examination
  • Prior to surgical operations such as cataract extraction 2
• Onset of action: usually begins within 30 seconds and persists for 15 minutes or longer 2

From the Research

Proparacaine Studies

• Proparacaine is a topical anesthetic used in ophthalmic procedures, with studies comparing its effectiveness to other anesthetics such as lidocaine and tetracaine 3, 4, 5.
• A study published in 2021 found that 0.5% proparacaine drops were as effective as 3.5% lidocaine gel in providing anesthesia for intravitreal injections, with no statistical difference in pain scores between the two groups 3.
• Another study published in 2024 compared the effectiveness of 0.5% and 0.25% proparacaine hydrochloride eye drops and found that both concentrations were effective in providing topical anesthesia for routine ocular procedures, with no significant difference in pain scores between the two groups 5.
• A study published in 2017 compared the corneal anesthetic effect and ocular tolerance of 3.5% lidocaine gel, 0.5% aqueous proparacaine, and 0.5% viscous tetracaine in normal canines, and found that tetracaine provided a significantly longer duration of corneal anesthesia than proparacaine or lidocaine 4.
• An older study published in 1980 found that low concentrations of proparacaine (0.125%, 0.25%, and 0.5%) were effective in providing anesthesia for tonometry, with 0.25% proparacaine being an effective anesthetic dose for all patients 6.
• The use of proparacaine as a topical anesthetic has been shown to be safe and effective, with minimal side effects, such as conjunctival hyperemia and blepharospasm 3, 4, 5.

Comparison to Other Anesthetics

• Proparacaine has been compared to other anesthetics, such as lidocaine and tetracaine, in terms of its effectiveness and safety 3, 4.
• A study published in 2024 found that chloroprocaine 3% gel was a valid alternative to tetracaine 0.5% eye drops for ocular surface anesthesia in patients undergoing cataract surgery 7.
• The choice of anesthetic may depend on the specific procedure and patient population, with proparacaine being a viable option for routine ophthalmic procedures 5.