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Bedside Snapshot
  • Core Use: Topical ophthalmic anesthetic for short procedures (tonometry, foreign body removal, corneal exam) and component of topical mixtures for laceration repairs (e.g., LET: lidocaine-epinephrine-tetracaine)
  • Standard Ophthalmic Dose: 0.5% solution, 1–2 drops in the eye before procedure; can repeat once or twice at 5–10 minute intervals
  • Onset/Duration: Onset 30 seconds to 1 minute (ocular); duration 10–20 minutes for ophthalmic use
  • Key Danger: Repeated/prolonged ocular use causes corneal toxicity (keratitis, ulceration); higher risk of allergic reactions than amide anesthetics (PABA-related); systemic toxicity with large doses on mucosa/abraded skin
  • Special Note: Should NOT be sent home for eye pain control due to corneal toxicity risk with unsupervised repeated use
Brand & Generic Names
  • Generic Name: Tetracaine hydrochloride
  • Brand Names: Pontocaine, Tetravisc, various generics; component of some topical mixes (e.g., LET)
Medication Class

Ester-type local anesthetic

Pharmacology

Mechanism of Action:

  • Blocks voltage-gated sodium channels in neuronal cell membranes, inhibiting the initiation and conduction of nerve impulses
  • Preferentially affects small, unmyelinated fibers (pain, temperature) before larger motor fibers, leading to localized loss of sensation
  • As an ester local anesthetic, tetracaine is hydrolyzed by plasma and tissue esterases to para-aminobenzoic acid (PABA) and other metabolites
  • PABA may be involved in allergic reactions (higher risk than amide anesthetics)

Pharmacokinetics:

  • Onset (ocular topical): Usually within 30 seconds to 1 minute after 0.5% drops
  • Duration (ocular): Approximately 10–20 minutes of anesthesia for most patients
  • Topical skin (LET): Onset typically within 20–30 minutes when applied under occlusion; duration sufficient for many simple laceration repairs
  • Absorption: Systemic absorption depends on surface area, vascularity, epithelial integrity, and presence of epinephrine (which reduces systemic uptake)
  • Metabolism: Ester metabolism via plasma cholinesterases is relatively rapid, but in infants, patients with atypical cholinesterase, or large exposures, accumulation and toxicity are possible
Dosing & Administration

Available Forms:

  • Ophthalmic solution: 0.5% tetracaine (5 mg/mL) in dropper bottles; sometimes 0.45–1% in regional preparations
  • Ophthalmic gel: 0.5% viscous gel for longer contact with ocular surface
  • Topical combinations for wound anesthesia (institution-specific): LET solution/gel (typical: lidocaine 4%, epinephrine 1:2,000, tetracaine 0.5%; concentrations vary)
  • Injectable spinal formulations (e.g., 0.5–1% tetracaine for spinal anesthesia) exist but are typically used by anesthesia in OR settings rather than in routine ED practice

Dosing – Tetracaine (Adult Topical/Ocular; always follow local protocol):

Indication / Route Typical Concentration Dose / Frequency Notes
Ocular anesthesia for exam/foreign body removal 0.5% ophthalmic solution 1–2 drops in affected eye(s); may repeat q5–10 min up to 3–4 doses Avoid repeated/prolonged outpatient use; risk of corneal toxicity and delayed healing
Ocular anesthesia for short procedures (suturing corneal/conjunctival lac) 0.5% solution or gel 1–2 drops or thin ribbon of gel before procedure; repeat sparingly as needed Monitor corneal status; avoid frequent re-dosing
Topical LET for laceration repair (skin) LET: lidocaine 4%, epinephrine, tetracaine 0.5% (typical) Apply 1–3 mL on pledget or directly into wound; occlude for 20–30 min Avoid end-arterial areas (fingers, nose tip, penis, toes) due to epinephrine; max volume per local protocol
Topical mucosal anesthesia (e.g., nasal/oral) 0.5–1% solution or mixed spray Minimal effective amount applied with swab or spray Use cautiously; high systemic absorption risk on mucosa; often combined with other agents and under specialist protocols
Pediatric ocular anesthesia 0.5% ophthalmic solution 1 drop in affected eye; may repeat once or twice with caution Use minimal dose needed; monitor for rubbing and corneal injury
Contraindications

Contraindications:

  • Known hypersensitivity to tetracaine, other ester local anesthetics (e.g., procaine, chloroprocaine), or formulation components
  • History of severe reaction to PABA-containing compounds or ester anesthetics
  • Use in patients unable to avoid eye rubbing or who cannot be monitored for corneal injury after ophthalmic administration (relative; requires careful supervision)

Major Precautions:

  • Repeated or prolonged topical ocular use can cause keratitis, corneal epithelial defects, corneal ulceration, and even perforation; avoid dispensing for home use for eye pain
  • Large-area or prolonged topical application (especially to mucous membranes or abraded skin) increases risk of systemic toxicity (CNS excitation, seizures, CNS depression, cardiovascular collapse)
  • Use caution in infants, young children, and patients with impaired plasma cholinesterase activity, as ester metabolism may be reduced
  • Because it is an ester, tetracaine has a higher risk of allergic reactions than many amide anesthetics; consider amide alternatives (lidocaine, proparacaine ophthalmic) in patients with suspected ester allergy
  • Avoid LET or other epinephrine-containing mixtures in areas with end-artery blood supply (fingers, nose tip, penis, toes) unless institutional protocols specifically support their use
Adverse Effects

Common (Topical/Ocular):

  • Transient burning or stinging on instillation
  • Temporary blurred vision or tearing (ocular)
  • Superficial punctate keratitis with repeated dosing
  • Local erythema or irritation at skin application sites

Serious (rare, usually with misuse or large exposures):

  • Corneal ulceration, stromal infiltration, or perforation with repeated/abusive topical ocular use
  • Allergic reactions including urticaria, bronchospasm, or anaphylaxis (especially in ester-allergic individuals)
  • Systemic local-anesthetic toxicity: perioral numbness, tinnitus, metallic taste, agitation, seizures, CNS depression, arrhythmias, cardiovascular collapse
  • Methemoglobinemia when combined with other oxidizing topical anesthetics (benzocaine, prilocaine) in mucosal mixtures
Special Populations

Pediatric:

  • Use minimal effective dose in children; monitor closely for eye rubbing and corneal injury after ophthalmic use
  • LET is particularly useful in pediatric laceration repairs to avoid painful injections
  • Risk of systemic toxicity higher in infants due to reduced esterase activity

Elderly:

  • Use standard doses but monitor closely for corneal healing
  • May have reduced corneal sensitivity and healing capacity

Pregnancy & Lactation:

  • Limited data on topical tetracaine in pregnancy; use when benefit outweighs risk
  • Systemic absorption from topical use is generally low

Patients with Cholinesterase Deficiency:

  • May have prolonged effects and increased risk of toxicity
  • Use minimal doses and monitor closely
Monitoring

Clinical Monitoring:

  • For ocular use: assess corneal surface before and after procedures (fluorescein staining, slit lamp if available) for epithelial defects or ulceration
  • Observe for persistent eye pain, photophobia, or visual changes after topical tetracaine; these may indicate corneal injury requiring ophthalmology evaluation
  • In LET or other topical skin use, monitor total volume and application area, especially in small children, to avoid systemic toxicity
  • Monitor for signs of local-anesthetic systemic toxicity (CNS/cardiovascular) in patients receiving repeated or large-area applications
  • In patients with suspected allergy, have resuscitation equipment and alternative agents available
Indications / Clinical Uses (ED/EMS)
  • Short-term topical anesthesia of the eye for diagnostic and minor therapeutic procedures: tonometry, gonioscopy, removal of foreign bodies, suturing superficial corneal/conjunctival lacerations, and facilitating thorough corneal exam/fluorescein staining
  • Topical anesthesia of skin and mucous membranes (often as part of compound preparations like LET or TAC) before laceration repair or minor procedures, especially in pediatrics
  • Topical anesthesia of mucosa (e.g., nasal, oropharyngeal) in some procedural settings, usually under anesthesia/ENT protocols (risk of systemic absorption and methemoglobinemia when combined with other agents)
Clinical Pearls
Never Send Home: Topical tetracaine is fantastic for getting a good look at a miserable, photophobic cornea, but it should generally NOT be sent home for pain control due to corneal toxicity risk with repeated unsupervised use.
LET for Pediatric Lacerations: For pediatric lacerations, LET (with tetracaine) can dramatically reduce the need for injected anesthetic if you give it enough time (20–30 minutes under occlusion) and choose appropriate wound locations.
Topical Anesthetic Abuse: If you see persistent epithelial defects, stromal haze, or severe ongoing eye pain in a patient who has had frequent anesthetic drops, think about topical anesthetic abuse and involve ophthalmology early.
Ester vs Amide Allergy: In patients with a strong history of local anesthetic allergy, clarifying whether the reaction was to an ester or an amide can guide whether tetracaine (ester) is appropriate or whether an amide ophthalmic (e.g., proparacaine) is safer.
Smallest Effective Dose: As with all local anesthetics, use the smallest effective dose over the smallest area needed, especially on mucous membranes and in children, to avoid systemic toxicity.
References
  • 1. Lexicomp. (2024). Tetracaine (systemic and topical): Drug information. Wolters Kluwer.
  • 2. Seaberg, D. C., & Hughes, J. A. (1996). LET (lidocaine–epinephrine–tetracaine) solution versus TAC (tetracaine–adrenaline–cocaine) for topical anesthesia of lacerations in children. Annals of Emergency Medicine, 28(6), 627–631.
  • 3. Fraunfelder, F. W. (2004). Corneal toxicity from topical ocular anesthetics. Cornea, 23(4), 365–367.
  • 4. Tintinalli, J. E., Ma, O., Yealy, D. M., et al. (2019). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (9th ed.). McGraw-Hill.
  • 5. DrugBank Online. (2024). Tetracaine. https://go.drugbank.com/
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