Tetracaine (Pontocaine)

Emergency & Prehospital

• Eye pain that prevents examination: the drop numbs the cornea and conjunctiva, so an eye that is light-sensitive and squeezing shut can be opened for inspection and fluorescein staining
• Chemical eye exposure: numb the eye before and during irrigation, so the patient can sit through a long flush (Paramedic/RN, per local protocol)
• Corneal or conjunctival foreign body: the drop lets you look, flip the lid and remove the object

ED / ICU / Transport

• Short ophthalmic procedures: tonometry, gonioscopy, slit-lamp exams and any other eye procedure that needs fast, short-lived numbing (FDA-labeled indication)
• Laceration repair: tetracaine 0.5% is one part of compounded LET (lidocaine-epinephrine-tetracaine) gel or solution. You put it on the open wound before suturing, especially in children (off-label, compounded)
• Mucous membrane anesthesia: sprays and liquids (benzocaine-butamben-tetracaine) for work in the nose, mouth, pharynx, larynx, trachea, bronchi and esophagus. They blunt the gag reflex, which makes them useful before endoscopy or an awake airway procedure (see intubation)

Other Uses

• Spinal anesthesia: tetracaine 1% injection for procedures that last 2–3 hr. Only anesthesia clinicians give it
• Superficial dermatologic procedures on intact skin: lidocaine 7%/tetracaine 7% cream in adults, before laser, dermal filler and tattoo-removal work
• Dental anesthesia: the tetracaine-oxymetazoline nasal spray is for restorative work on maxillary teeth. Availability is uncertain

Doses vary by protocol; follow local protocols and medical direction.

Available Forms

• Ophthalmic solution 0.5% (5 mg/mL): tetracaine hydrochloride 0.5% (equivalent to 0.44% tetracaine base). Multi-dose 5 mL and 15 mL dropper bottles (preserved) and 4 mL single-patient-use units (preservative-free; discard after use). This is the form EMS, EDs and transport services carry.
• LET (compounded): lidocaine 4%, epinephrine 0.1%, tetracaine 0.5% gel or solution, for example as a 3 mL unit dose. Compounding pharmacies do not all mix the same strength. Read the label.
• Benzocaine-butamben-tetracaine (Cetacaine): benzocaine 14%, butamben 2%, tetracaine HCl 2% spray and liquid for mucous membranes. A 1-second spray gives about 200 mg of product, and 4 mg of that is tetracaine HCl.
• Lidocaine-tetracaine cream (Pliaglis): lidocaine 7%/tetracaine 7% for intact skin in adults.
• Tetracaine-oxymetazoline nasal spray (Kovanaze): 6 mg tetracaine HCl and 0.1 mg oxymetazoline HCl per 0.2 mL single-dose sprayer, dental use. DailyMed lists its only NDC as inactivated, so availability is uncertain.
• Tetracaine 1% injection (10 mg/mL): preservative-free, for spinal anesthesia only.

Adult Dosing

Pediatric Dosing

Check the volume against weight-based dosing.

Preparation & Administration

• Eye drops: instill 1 drop without touching the dropper tip to the eye or any surface. Single-patient-use units contain no preservative: discard after use.
• After instillation: the eye stays numb for up to 20 min. Tell the patient not to touch or rub it for at least 10–20 min.
• Inspect before use: do not use a solution that contains crystals or is cloudy or discolored.
• LET: place the gel or a soaked pledget in and over the wound, cover with an occlusive dressing, wait 20–30 min, then test the wound edges before suturing. Open skin wounds only: never on mucous membranes (mouth, inner lip, nose, genitals). Epinephrine is in the mix, so some services keep it off end-artery sites (digits, nasal tip, pinna, penis). That is institutional practice. No guideline source was verified.
• Mucosal spray: the tissue does not have to be dried first. Apply it straight to the site that needs numbing. Do not leave it under dentures or cotton rolls.
• Total dose: add up every local anesthetic the patient receives (topical, infiltrated and nebulized lidocaine, benzocaine, tetracaine).

Contraindications

• Eye drops: hypersensitivity to any component (Bausch & Lomb label; the Alcon single-patient-use label lists none)
• Ester or para-aminobenzoic acid (PABA) allergy: a labeled contraindication for the spinal injection (PABA or its derivatives), Pliaglis and Kovanaze. Avoid the eye drops too. The cross-sensitivity runs through the whole class
• Cetacaine: children under 2 yr; use on the eyes; injection; large areas of denuded or inflamed tissue; hypersensitivity to any ingredient; known plasma cholinesterase deficiency; use under dentures or cotton rolls (escharotic effect)
• Spinal injection: standard contraindications to spinal anesthesia (e.g. septicemia, infection at the site, uncontrolled hypotension)

Precautions

• Not for injection or intraocular use (eye-drop label warning): intracameral use damages the corneal endothelium. Do not instill in a suspected open globe or penetrating eye injury. Never inject a topical product.
• Provider administration only (eye-drop label warning): the patient does not self-dose. Never dispense drops for home use.
• Repeated ocular dosing: prolonged use or abuse brings epithelial toxicity to the cornea, and it can progress to permanent damage.
• Plasma cholinesterase deficiency: the ester breaks down more slowly. Use caution. For Cetacaine it is a contraindication.
• Methemoglobinemia risk: G6PD deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months, and other oxidizing drugs.
• Mucosa, abraded skin, large areas: they let the drug into the bloodstream faster. Use the smallest amount over the smallest area, and stay inside labeled amounts and contact times. Never apply LET to mucous membranes.
• Debilitated, older or acutely ill patients: reduce mucosal and spinal doses.

Common

• Transient stinging or burning on instillation
• Conjunctival redness, eye irritation, eye pain or discomfort
• Skin blanching where LET is applied (expected epinephrine effect)
• Contact dermatitis (erythema, itching, vesicles) after prolonged or repeated aminobenzoate exposure

Serious / Life-Threatening

Overdose & Toxicity Management

• Signs: CNS excitation or depression (nervousness, dizziness, tremor, drowsiness, seizures, coma) and cardiovascular depression (hypotension, arrhythmia, arrest). Here's what people miss: excitation may be absent, and drowsiness can be the first sign.
• Immediate management: stop the anesthetic, call for help, secure the airway and give oxygen. Treat seizures with a benzodiazepine (midazolam, lorazepam); if only propofol is available, use small doses (e.g. 20 mg increments).
• 20% lipid emulsion, per the ASRA 2020 checklist: over 70 kg: bolus about 100 mL over 2–3 min, then about 250 mL over 15–20 min. 70 kg or less (including children): bolus about 1.5 mL/kg over 2–3 min, then about 0.25 mL/kg/min. Still unstable: repeat the bolus and double the infusion. Continue at least 15 min after stability; max 12 mL/kg.
• Arrest or arrhythmia: LAST resuscitation is not standard ACLS, so go light on epinephrine doses (start with 1 mcg/kg or less). Avoid vasopressin, calcium-channel blockers, β-blockers and more local anesthetic (including lidocaine).
• Methemoglobinemia: methylene blue 1 mg/kg IV over 5–30 min (adults and children); repeat 1 mg/kg after 1 hr if methemoglobin stays above 30% or symptoms persist. eGFR 15–59 mL/min/1.73 m²: single dose only. Not resolved after 2 doses (or 1 hr after the single renal dose): consider alternative treatment with a poison center. Contraindicated in G6PD deficiency (hemolysis); serotonin syndrome risk with serotonergic drugs (boxed warning).
• Observation once stable: at least 2 hr after a seizure and 4–6 hr after cardiovascular instability.
• Ocular overdose: long use can leave the cornea permanently cloudy or ulcerated. Get ophthalmology involved.

Clinically Significant Interactions

Never give tetracaine IV, so IV compatibility data do not apply.

• Pediatrics: Ophthalmic tetracaine is labeled for children, and it is safe there. LET spares a child the painful injection at a laceration. Cetacaine is contraindicated under 2 yr. The lidocaine-tetracaine cream is not established in children, since it failed to show benefit for venipuncture at 5–17 yr. The dental nasal spray is limited to 40 kg and above. See the Pediatric Dosing table.
• Neonates and Young Infants: infants under 6 months are more prone to methemoglobinemia from local anesthetics. Use the smallest amount and monitor.
• Pregnancy: There are no adequate human studies, and no published animal reproduction studies either. Systemic exposure after eye drops has not been studied. The Cetacaine label says to avoid it in early pregnancy unless the benefit outweighs the unknown risk. Do not hold back an eye exam or irrigation the patient needs.
• Lactation: There are no data on excretion into human milk. Absorbed drug breaks down fast in plasma. Weigh the clinical need against the unknown infant risk.
• Older Adults: Ophthalmic use shows no overall difference by age. Debilitated or acutely ill older adults get smaller mucosal and spinal doses.
• Renal Impairment: No specific adjustment is established for tetracaine itself. The methylene blue rescue drops to a single dose when eGFR is 15–59 mL/min/1.73 m² (see Adverse Effects & Toxicity).
• Hepatic Impairment: No specific adjustment is established. Breakdown runs through plasma pseudocholinesterase and ocular esterases.
• Obesity / Dosing Weight: Adult topical doses are fixed. No pediatric LET volume is established. The adult 3 mL maximum is a ceiling, not a pediatric dose.
• Plasma Cholinesterase Deficiency: Ester metabolism runs slower, so toxicity risk climbs. Use caution, and avoid Cetacaine.
• G6PD Deficiency: The risk of methemoglobinemia is higher. Methylene blue is contraindicated, so discuss treatment with a poison center.

• Scope: Some EMS protocols let a Paramedic instill an ophthalmic anesthetic before irrigating a chemical eye exposure. RN and critical-care transport clinicians may give it per protocol. Scope varies by state and agency protocol.
• Storage & Stability: protect from light. Multi-dose bottles: 15–25°C (59–77°F); single-patient-use units: 2–25°C (36–77°F). If crystals form or the solution turns cloudy or discolored, discard it. Keep it out of vehicle heat.
• Carried Concentration: The eye gets 0.5% ophthalmic solution and nothing else. LET, mucosal sprays and creams stay out of the eye.
• Eye Trauma: with a suspected open globe or penetrating eye injury, the drops stay in the box. Shield the eye without pressure on the globe and transport (per protocol).
• Chemical Eye Exposure: Anesthetize, then start irrigation right away and keep it going en route. Don't let a search for the drops hold up the flush.
• Handoff Essentials: agent and time of each drop or application, total volume (LET) or spray time, eye findings before anesthesia, irrigation volume and duration, and any toxicity signs.

Mechanism of Action

• It blocks voltage-gated sodium channels in nerve membranes. No impulse starts, and none gets through. The result is reversible local anesthesia.
• This is an ester (amino-ester) local anesthetic, a cousin of procaine. Hydrolysis breaks it into p-butylaminobenzoic acid (a para-aminobenzoic acid (PABA) derivative) and dimethylaminoethanol. Those PABA-type metabolites are the usual cause of ester allergy.
• In LET, the epinephrine tightens wound vessels. Less drug gets absorbed, so the contact lasts longer.

Pharmacokinetics

• Half-life: not established for topical use. Systemic exposure after eye drops has not been studied.
• Metabolism: Plasma pseudocholinesterase and nonspecific tissue esterases, ocular ones included, break it down into p-butylaminobenzoic acid and dimethylaminoethanol.
• Elimination: The inactive metabolites leave in the urine.

Generic Name

Tetracaine hydrochloride (amethocaine outside the US)

Brand Names

Pontocaine (brand no longer listed on DailyMed; generic ophthalmic solution and injection available); combinations: Cetacaine (with benzocaine and butamben), Pliaglis (with lidocaine), Kovanaze (with oxymetazoline); LET is compounded

Pharmacologic Class

Ester (amino-ester) local anesthetic

Therapeutic Class

Topical ophthalmic, mucosal and dermal anesthetic; spinal anesthetic

Controlled Substance

Not controlled

High-Alert

No for topical use. Intrathecal (spinal) use: anesthesia clinicians only.