P-caine0.5%

P-caine is an ester-type topical ophthalmic local anesthetic used by eye care professionals to produce rapid, short-duration numbness of the surface of the eye. It is an FDA-approved, established treatment for the following in-office procedures:

• Tonometry (measurement of intraocular pressure)
• Gonioscopy (examination of the eye's drainage angle)
• Removal of corneal or conjunctival foreign bodies
• Removal of corneal sutures
• Other short diagnostic or minor surgical procedures on the cornea or conjunctiva requiring brief topical anesthesia

P-caine is intended strictly for short-duration, professionally administered ocular anesthesia. It is not indicated, and must not be used, for at-home or repeated self-treatment of eye pain (see Precautions and Warnings).

Each mL of Proparacaine Hydrochloride ophthalmic solution contains Proparacaine Hydrochloride 5 mg (0.5% w/v) as the active ingredient in a sterile, isotonic, buffered aqueous vehicle, typically preserved with benzalkonium chloride.

P-caine is a rapid-onset, short-acting ester-type local anesthetic formulated as a sterile ophthalmic solution for topical use on the eye. When instilled onto the ocular surface, P-caine produces corneal and conjunctival anesthesia within about 20 seconds, lasting approximately 15-20 minutes, which allows brief eye examinations and minor procedures to be performed without patient discomfort.

Ophthalmic Local Anesthetic (Ester-type)

Mechanism

Proparacaine Hydrochloride blocks the initiation and conduction of nerve impulses in sensory nerve endings of the cornea and conjunctiva by reversibly stabilizing the neuronal membrane and reducing its permeability to sodium ions, thereby preventing depolarization and blocking pain signal transmission.

Onset and Duration

After topical instillation, Proparacaine Hydrochloride produces anesthesia within approximately 20 seconds, with peak effect around 30 seconds and duration of action of about 15-20 minutes.

Absorption

Systemic absorption of Proparacaine Hydrochloride following topical ocular use is minimal under normal single-dose use.

P-caine ophthalmic solution is for topical application to the eye only - it must never be injected. It is administered as eye drops by a healthcare professional in a clinical setting, immediately before the intended examination or procedure. The lower eyelid may be gently pulled down and the drop instilled into the conjunctival sac, avoiding contact of the dropper tip with the eye or surrounding tissue to prevent contamination.

P-caine has minimal systemic absorption after topical ocular use, so clinically significant systemic drug interactions are unlikely. Notable considerations include:

• Other topical ophthalmic anesthetics: Concomitant or closely repeated use of other local anesthetic eye drops with P-caine may increase the risk of corneal epithelial toxicity and is not recommended outside professional guidance.
• Other topical eye medications: When more than one topical ophthalmic product is required, they should be administered several minutes apart to avoid dilution or washout of P-caine.

Side effects of P-caine are generally local and transient:

Pregnancy: Adequate, well-controlled studies of P-caine in pregnant women have not been conducted. P-caine should be used during pregnancy only if clearly needed, after the potential benefit to the mother is weighed against the potential risk to the fetus, and only under a physician's direction.

Lactation: It is not known whether P-caine is excreted in human breast milk. Caution should be exercised when P-caine is administered to a nursing woman, and a physician should be consulted.

P-caine is intended solely for short-duration, professionally supervised use in a clinical setting. Important precautions include:

• Not for self-administration or home use: P-caine must never be prescribed or dispensed for outpatient, home, or repeated self-administration.
• Risk of serious corneal injury with misuse: Repeated or prolonged use of P-caine is a well-recognized cause of corneal toxicity, delayed epithelial healing, and permanent corneal opacification with vision loss. Because P-caine relieves pain, it can mask a serious ocular injury or infection, allowing progressive corneal damage to occur silently without the warning of pain.
• Protect the anesthetized eye: After instillation, the protective blink and pain reflexes are temporarily lost. Patients must be advised, and if needed protected, from rubbing the eye or allowing foreign material to contact it until normal sensation fully returns.
• Not for treating ocular pain: P-caine must not be used to self-treat eye pain, red eye, or any ocular condition at home.
• Topical use only: Never inject P-caine.
• Inspect before use: Discard the solution if it becomes discolored (darker than a light straw color) or cloudy.
• Single-patient, office-administered use: P-caine is intended for single-use or short-course administration under direct clinical supervision, not for take-home or shared use.
• Contact lenses: Soft contact lenses should not be worn during or immediately after P-caine administration.

Excessive or repeated instillation of P-caine beyond the recommended professional dosing can cause corneal epithelial toxicity, persistent anesthesia, and delayed healing. Accidental ingestion or significant systemic exposure (e.g., in a child) could theoretically produce systemic local-anesthetic-type effects such as dizziness, drowsiness, or cardiovascular disturbance, although this is rare with topical ocular use. If overdose, accidental ingestion, or an unexpected reaction involving P-caine is suspected, seek immediate medical attention or contact a poison control center/emergency services without delay; do not attempt home treatment.

Store P-caine ophthalmic solution under refrigeration (2°C-8°C) prior to dispensing. Once dispensed for clinical use, it may be kept at room temperature (below 25°C), away from light, for the period specified by the pharmacist or physician. Keep the container tightly closed, protect from light, discard if the solution is discolored, and keep out of the reach of children.

Renal or hepatic impairment: Because systemic absorption of P-caine after topical ocular use is minimal, no specific dose adjustment is established for renal or hepatic impairment.

Elderly: No specific dose adjustment is required for P-caine in elderly patients; standard professional dosing applies.

Pediatric patients: See Pediatric Uses. In all populations, P-caine must be administered only by, or under the direct supervision of, a qualified healthcare professional (see Precautions and Warnings).

P-caine is used for the duration of a single diagnostic test or minor procedure only - typically a single dose or a brief series of doses over a few minutes within one clinical visit. It is not intended for continued, extended, or repeated use across multiple days; such use is unsafe and is a well-recognized cause of corneal injury (see Precautions and Warnings).

Ophthalmic local anesthetics; Ester-type local anesthetics

Proparacaine Hydrochloride reversibly blocks voltage-gated sodium channels in the sensory nerve endings of the cornea and conjunctiva, stabilizing the neuronal membrane and preventing the influx of sodium ions required for depolarization. This blocks the initiation and conduction of pain-signal nerve impulses, producing localized loss of sensation at the ocular surface.

C

P-caine may be used by an ophthalmologist or other qualified clinician in pediatric patients for the same short diagnostic and minor procedural indications as in adults (e.g., tonometry, foreign body removal), using the minimum effective number of drops. Formal dose-ranging studies establishing pediatric dosing have not been extensively published, and the safety and efficacy of unsupervised or home use of P-caine in children have not been established. Children receiving P-caine should be closely supervised so they do not rub or injure the temporarily anesthetized eye.