Zolazepam and Tiletamine
**Zolazepam/Tiletamine** (commonly known by trade names such as Zoletil or Telazol) is a combination injectable anesthetic agent widely used in veterinary medicine for general anesthesia in dogs and cats. It combines a dissociative anesthetic (tiletamine) with a benzodiazepine (zolazepam) to provide anesthesia with concurrent muscle relaxation. > **Clinical Warning:** The combined product should **not** be used as the sole anesthetic agent for painful operations. It lacks sufficient visceral analgesia and must be combined with an appropriate analgesic (e.g., opioids, NSAIDs). **Clinical Pearl:** Recovery from this combination can be prolonged (2-6 hours) and sometimes rough or excitable, particularly in dogs given higher doses. Premedication (e.g., with alpha-2 agonists or phenothiazines, though noting interactions) often increases the smoothness of recovery. Recovery is generally more prolonged in cats than in dogs.
Mecanismo: The drug is a 1:1 combination of two active principles with complementary mechanisms: * **Zolazepam:** A benzodiazepine that enhances the activity of **GABA** (gamma-aminobutyric acid) → the major inhibitory neurotransmitter within the CNS. This provides sedative, anxiolytic, and muscle-relaxing actions, counteracting the muscle rigidity typically caused by dissociative agents. * **Tiletamine:** A dissociative anesthetic (pharmacologically similar to ketamine) that antagonizes **NMDA (glutamic acid) receptors** → depresses certain cerebral regions (thalamus and cortex) while the limbic system remains active, generating a state of dissociative anesthesia.
Dosificación por especie
- General anaesthesia · 5-10 mg/kg · IV · single dose · Duration of anaesthesia is 20-60 minutes · Dose refers to the combined tiletamine/zolazepam (100 mg/ml). Adjust depending on degree of pain expected and depth required.
- General anaesthesia · 7-25 mg/kg · IM · single dose · Duration of anaesthesia is 20-60 minutes · Dose refers to the combined tiletamine/zolazepam (100 mg/ml). Adjust depending on degree of pain expected and depth required.
- General anaesthesia · 5-7.5 mg/kg · IV · single dose · Duration of anaesthesia is 20-60 minutes · Dose refers to the combined tiletamine/zolazepam (100 mg/ml). Adjust depending on degree of pain expected and depth required.
- General anaesthesia · 10-15 mg/kg · IM · single dose · Duration of anaesthesia is 20-60 minutes · Dose refers to the combined tiletamine/zolazepam (100 mg/ml). Adjust depending on degree of pain expected and depth required.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Severe cardiac disease
- Severe respiratory disease
- Hypertensive disease
- Renal insufficiency
- Pancreatic insufficiency
- Hepatic insufficiency
- Head trauma or intracranial tumours
- Pregnancy (crosses the placenta and causes fatal respiratory depression in neonates)
Efectos adversos
- Excessive salivation (ptyalism)
- Muscle rigidity during recovery
- Prolonged and excitable recovery (especially in dogs at higher doses)
- Pain on intramuscular injection (particularly in cats)
- Respiratory depression (can be fatal in neonates)
- Hypothermia
Interacciones farmacológicas
- Phenothiazines (e.g., Acepromazine) · Increased cardiorespiratory depression and increased hypothermic effect during the last phase of anesthesia. · major
- Chloramphenicol · Slows down the elimination of the anesthetics if used during the pre- or intraoperative period. · moderate
Monitorización
- Heart rate and rhythm
- Respiratory rate and depth
- Body temperature (monitor closely for hypothermia)
- Depth of anesthesia (jaw tone, palpebral reflex)
- Quality of recovery (monitor for excitation or rigidity)
Sobredosis
Overdosage increases the risk of severe **cardiorespiratory depression**, prolonged anesthesia, and highly excitable or rough recoveries. Treatment is supportive, including mechanical ventilation if respiratory failure occurs, thermal support for hypothermia, and potentially benzodiazepine antagonists (flumazenil) for the zolazepam component, though this leaves the tiletamine unopposed.
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.