OPHTHAINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OPHTHAINE (OPHTHAINE).
Local anesthetic that blocks sodium ion channels in neuronal membranes, preventing initiation and conduction of nerve impulses, thereby producing local anesthesia.
| Metabolism | Primarily hydrolyzed by plasma esterases; metabolites excreted in urine. |
| Excretion | Primarily metabolized by plasma esterases; renal excretion of metabolites accounts for >90% of elimination, with <5% excreted unchanged in urine. Biliary/fecal elimination is negligible. |
| Half-life | Terminal elimination half-life is approximately 10-15 minutes, reflecting rapid hydrolysis by esterases, resulting in very short systemic exposure. |
| Protein binding | Approximately 40-50% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Approximately 1.0-1.5 L/kg, indicating extensive tissue distribution, though clinical relevance is limited due to rapid metabolism. |
| Bioavailability | Topical ophthalmic: negligible systemic bioavailability (<5%) due to small dose and rapid local metabolism; intravenous: 100% (not used clinically). |
| Onset of Action | Topical ophthalmic: corneal anesthesia within 30 seconds; peak effect within 1-2 minutes. |
| Duration of Action | Cornel anesthesia lasts 15-20 minutes; complete recovery of corneal sensitivity occurs within 30-45 minutes. |
1-2 drops of 0.5% solution to the affected eye(s) as a single dose prior to tonometry or minor procedures; can be repeated in 5-10 minutes if needed.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dose adjustment required; systemic absorption is minimal. |
| Liver impairment | No dose adjustment required; drug undergoes rapid ester hydrolysis in plasma. |
| Pediatric use | Not recommended for children under 1 year; for older children, same as adult dosing (1-2 drops of 0.5% solution). |
| Geriatric use | No specific dose adjustment; use with caution in patients with cardiac conduction defects or hyperthyroidism. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OPHTHAINE (OPHTHAINE).
| Breastfeeding | Proparacaine is a topical ophthalmic anesthetic with negligible systemic absorption; therefore, excretion into breast milk is unlikely. No M/P ratio is available. It is considered compatible with breastfeeding with minimal risk to the infant. |
| Teratogenic Risk | Proparacaine (Ophthaine) is a topical ophthalmic anesthetic. Systemic absorption is minimal, and no teratogenic effects are reported in animal studies. There are no adequate human studies; however, due to negligible systemic exposure, risk is considered low. Use during pregnancy only if clearly needed. |
■ FDA Black Box Warning
Not for injection or prolonged use; corneal epithelial toxicity and stromal edema may occur with repeated application.
| Serious Effects |
["Hypersensitivity to proparacaine or any component of the formulation","Sulfite sensitivity (if formulation contains sulfites)","Prolonged use (risk of corneal damage)"]
| Precautions | ["Prolonged use may cause corneal epithelial damage, stromal edema, or delayed healing.","Risk of allergic reactions including contact dermatitis.","Use with caution in patients with cardiac disease or hyperthyroidism (potential for systemic absorption).","Patients should avoid rubbing eyes during anesthesia to prevent corneal abrasion."] |
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| Fetal Monitoring |
| No specific maternal fetal monitoring is required for topical ophthalmic use. Monitor for rare systemic adverse effects (e.g., methemoglobinemia) in the mother and fetus if applied excessively or to abraded cornea. |
| Fertility Effects | No studies on fertility effects in humans. Based on minimal systemic absorption, proparacaine is unlikely to impact fertility. |