PROPARACAINE HYDROCHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PROPARACAINE HYDROCHLORIDE (PROPARACAINE HYDROCHLORIDE).
Sodium channel blocker; reversibly stabilizes the neuronal membrane by inhibiting ion flux, thereby preventing the initiation and transmission of nerve impulses.
| Metabolism | Primarily hydrolyzed by plasma pseudocholinesterase (butyrylcholinesterase). |
| Excretion | Primarily metabolized by plasma esterases; renal excretion of metabolites accounts for >80% of elimination; <5% excreted unchanged in urine. |
| Half-life | Terminal elimination half-life is approximately 1.5 hours; clinically, the short half-life allows rapid recovery of corneal sensation. |
| Protein binding | Approximately 70% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Not well characterized due to local use; estimated Vd of ~1.2 L/kg after systemic absorption, indicating extensive tissue distribution. |
| Bioavailability | Topical ophthalmic: systemic bioavailability is low due to rapid metabolism in the eye and drainage; precise percentage not established, but systemic levels are negligible with normal dosing. |
| Onset of Action | Topical ophthalmic: 20–30 seconds after instillation, with complete anesthesia within 1 minute. |
| Duration of Action | Topical ophthalmic: 15–20 minutes for corneal anesthesia; duration may be prolonged with repeated instillations. |
1 to 2 drops of 0.5% solution in the eye every 5 to 10 minutes for 1 to 2 doses, or every 5 to 10 minutes for 3 to 5 doses for short procedures. For prolonged anesthesia, 1 to 2 drops every 5 to 10 minutes as needed.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required for ophthalmic use; negligible systemic absorption. |
| Liver impairment | No dosage adjustment required for ophthalmic use; negligible systemic absorption. |
| Pediatric use | 1 drop of 0.5% solution in the eye before procedure; may repeat in 5 minutes if needed. Maximum 2 doses per procedure. |
| Geriatric use | Same as adult dosing; monitor for possible corneal toxicity, especially with frequent use. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PROPARACAINE HYDROCHLORIDE (PROPARACAINE HYDROCHLORIDE).
| Breastfeeding | It is not known whether proparacaine hydrochloride is excreted in human milk after ophthalmic administration. Systemic absorption is minimal, and any amount excreted is likely negligible. Caution is advised when administered to a nursing woman. M/P ratio: Not available. |
| Teratogenic Risk | Proparacaine hydrochloride is a topical ophthalmic anesthetic. No adequate and well-controlled studies exist in pregnant women. Animal reproduction studies have not been conducted. As systemic absorption is minimal after ocular administration, the risk of teratogenicity is considered low. FDA Pregnancy Category C. Use during pregnancy only if potential benefit justifies potential risk to the fetus. |
■ FDA Black Box Warning
Not approved for injection or prolonged use; repeated use may cause corneal epithelial damage and delayed wound healing.
| Serious Effects |
Hypersensitivity to proparacaine or any component of the formulation; known allergy to ester-type local anesthetics.
| Precautions | Prolonged use may cause corneal damage, ulceration, and vision loss; do not touch the dropper tip to any surface to avoid contamination; use with caution in patients with cardiac disease, hyperthyroidism, or sulfite sensitivity. |
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| Fetal Monitoring | No specific maternal or fetal monitoring is required due to minimal systemic absorption. Standard monitoring for ophthalmic use (e.g., corneal integrity, intraocular pressure) applies. |
| Fertility Effects | No data exist on the effects of proparacaine hydrochloride on human fertility. Based on its local mechanism of action and minimal systemic absorption, it is unlikely to impair fertility. |