Etomidate
Etomidate is a short-acting, injectable non-barbiturate anesthetic agent. It is particularly valued in veterinary medicine for its **cardiovascular stability**, making it an excellent alternative to thiopental or propofol for anesthetic induction in compromised patients. **Key Clinical Highlights:** * **Hemodynamic Stability:** Causes minimal changes to heart rate, blood pressure, and cardiac output, making it ideal for patients with preexisting cardiac dysfunction or shock. * **Neurological Benefits:** Decreases cerebral blood flow, oxygen consumption, and intracranial pressure, which is beneficial for patients with head trauma. * **Endocrine Effects:** Reversibly inhibits the enzyme 11-beta-hydroxylase, leading to **adrenocortical suppression** (decreased cortisol production). Critically ill patients may require corticosteroid supplementation. * **Lack of Analgesia:** Etomidate provides hypnosis and amnesia but **no analgesia**; appropriate analgesic protocols must be used concurrently.
Mecanismo: While the exact mechanism is not definitively proven, etomidate is known to act primarily as a positive allosteric modulator and direct agonist at the **GABA_A receptor** in the central nervous system. * **Mechanism:** Binds to a specific site on the GABA_A receptor → enhances the affinity of the inhibitory neurotransmitter GABA for the receptor → increases transmembrane chloride conductance → hyperpolarizes the postsynaptic neuron → profound CNS depression and hypnosis. * **Endocrine Mechanism:** Directly inhibits **11-β-hydroxylase** (and to a lesser extent 17-α-hydroxylase) in the adrenal cortex → blocks the conversion of 11-deoxycortisol to cortisol → transient adrenal insufficiency.
Dosificación por especie
- As an induction agent · 1 mg/kg IV plus diazepam 0.5 mg/kg IV · IV · Once
- As an induction agent · 1-2 mg/kg rapidly IV · IV · Once
- As an induction agent · 0.5-2 mg/kg IV · IV · Once · Pre-medication is highly recommended to reduce incidence of side effects (myoclonus, vomiting). May be given with a benzodiazepine. Administration of a physiologic dose of dexamethasone or another short-acting glucocorticoid prior to etomidate is suggested.
- As an induction agent in the cardiovascular unstable patient · 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) · IV · Once
- As an induction agent in the cardiovascular unstable patient (Rabbits) · 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) · IV · Once
- As an induction agent · 1 mg/kg IV plus diazepam 0.5 mg/kg IV · IV · Once
- As an induction agent · 1-2 mg/kg rapidly IV · IV · Once
- As an induction agent · 0.5-2 mg/kg IV · IV · Once · Pre-medication is highly recommended to reduce incidence of side effects (myoclonus, vomiting). May be given with a benzodiazepine. Administration of a physiologic dose of dexamethasone or another short-acting glucocorticoid prior to etomidate is suggested.
Vías de administración
Contraindicaciones
- Known hypersensitivity to etomidate
- Maintenance of anesthesia (due to cumulative adrenal suppression)
- Use as a sole agent for painful procedures (lacks analgesia)
Efectos adversos
- Pain at intravenous injection site
- Myoclonus (skeletal muscle movements)
- Vomiting and post-operative retching
- Eye movements
- Hemolysis (due to propylene glycol carrier)
- Brief hypoventilation and decreased arterial blood pressure
- Apnea, laryngospasm, or hiccups (reported in humans)
Interacciones farmacológicas
- CNS/Respiratory Depressants (e.g., barbiturates, opiates, anesthetics) · Additive pharmacological effects; can increase CNS or respiratory depression.
- Verapamil · Associated with potentiating the anesthetic and respiratory depressant effects of etomidate.
Monitoreo
- Level of consciousness
- Respiration rate and depth
- Cardiovascular function (blood pressure, heart rate, ECG)
Sobredosis
Acute overdoses would be expected to cause enhanced pharmacologic effects of the drug, including profound CNS and respiratory depression. Treatment is supportive (e.g., mechanical ventilation, cardiovascular support) until the effects of the medication are diminished.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.