Tetracaine
**Tetracaine** (also known as **amethocaine**) is a topical local anaesthetic used primarily for the desensitization of the ocular surface (cornea and conjunctival sac). > **Clinical Pearl:** Although effective, it is uncommonly used in small animal practice because it tends to cause more marked conjunctival irritation and pain on application compared to alternatives like proxymetacaine. It must never be dispensed for ongoing therapeutic use due to severe corneal toxicity.
Mecanismo: Local anaesthetic action is dependent on the reversible blockade of the **voltage-gated sodium channels** → prevents the influx of sodium → inhibits the propagation of an action potential along the nerve fibre. Sensory nerve fibres are blocked before motor nerve fibres, allowing a selective sensory blockade at low doses.
Dosificación por especie
- Local anaesthesia of the ocular surface · 1 drop per eye · topical · single application · single dose · Uncommonly used; proxymetacaine is advised as an alternative.
- Local anaesthesia of the ocular surface · 1 drop per eye · topical · single application · single dose · Uncommonly used; proxymetacaine is advised as an alternative.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Therapeutic use (repeated administration for pain relief)
- Application prior to a Schirmer tear test
Efectos adversos
- Marked conjunctival irritation
- Chemosis
- Pain on application
- Corneal epithelial toxicity
- Delayed healing of corneal ulcers
Monitorización
- Corneal integrity (fluorescein staining if corneal damage is suspected)
Sobredosis
Overdosage in a clinical setting typically presents as local toxicity rather than systemic effects. Repeated administration leads to severe **corneal epithelial toxicity**, delayed healing of corneal ulcers, and potential corneal melting. > **Do not use for therapeutic purposes.**
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.