Etomidate
Carboxylic imidazole
Also known as: Amidate · Hypnomidate · Radenarcon · Sibul · R-16659
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an induction agent | 1 mg/kg IV plus diazepam 0.5 mg/kg IV | IV | Once | — | 🌎 NA |
| As an induction agent | 1-2 mg/kg rapidly IV | IV | Once | — | 🌎 NA |
| As an induction agent | 0.5-2 mg/kg IV | IV | Once | — | 🌎 NA |
- As an induction agent: 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.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an induction agent | 1 mg/kg IV plus diazepam 0.5 mg/kg IV | IV | Once | — | 🌎 NA |
| As an induction agent | 1-2 mg/kg rapidly IV | IV | Once | — | 🌎 NA |
| As an induction agent | 0.5-2 mg/kg IV | IV | Once | — | 🌎 NA |
- As an induction agent: 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.
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an induction agent in the cardiovascular unstable patient (Rabbits) | 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) | IV | Once | — | 🌎 NA |
Ferrets
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an induction agent in the cardiovascular unstable patient | 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) | IV | Once | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
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.
Mechanism of action
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.
Safety & warnings
Contraindications
- Known hypersensitivity to etomidate
- Maintenance of anesthesia (due to cumulative adrenal suppression)
- Use as a sole agent for painful procedures (lacks analgesia)
Adverse effects
- 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)
Precautions
Adrenocortical Suppression: Etomidate inhibits cortisol production. It should only be used for induction, not maintenance. Use with extreme caution in patients with impaired adrenocortical function. Exogenous glucocorticoids (e.g., dexamethasone) should be considered in severely compromised animals.
- Hepatic/Renal Impairment: Elimination half-lives may be significantly increased. The propylene glycol carrier may be problematic in patients with liver dysfunction.
- Hemolysis & Pain: Injecting into a running IV line is recommended to decrease pain on injection and potentially reduce hemolysis caused by the propylene glycol vehicle.
- Premedication: Administering a benzodiazepine (diazepam, midazolam) or opiate prior to etomidate can minimize myoclonus, vomiting, and potential seizure-like activity.
Drug interactions
Additive pharmacological effects; can increase CNS or respiratory depression.
Associated with potentiating the anesthetic and respiratory depressant effects of etomidate.
Monitoring
- Level of consciousness
- Respiration rate and depth
- Cardiovascular function (blood pressure, heart rate, ECG)
Pharmacokinetics
Absorption
After intravenous injection, etomidate is rapidly distributed into the CNS.
Distribution
Rapidly cleared from the brain back into systemic tissues. Duration of hypnosis is short (3-5 minutes) and dose-dependent. 75% bound to plasma proteins.
Metabolism
Rapidly metabolized in the liver primarily via hydrolysis or glucuronidation to inactive metabolites.
Elimination
The majority of the drug and metabolites are excreted into the urine, with the remainder into the bile and feces. Elimination half-life ranges from 1.25-5 hours in humans.
Overdose
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.
Available products
Formulations
- Injection: 2 mg/mL
Human-labeled
- Etomidate Injection: 2 mg/mL in 10 mL & 20 mL single-dose vials, 10 mL & 20 mL amps and 20 mL Abboject syringes; Amidate® (Hospira); generic
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Unless otherwise labeled, store etomidate injection at room temperature and protect from light.
Client information
Etomidate is a potent sedative-hypnotic anesthetic agent.
- Professional Use Only: It is used strictly by veterinary professionals in a clinical setting where adequate patient monitoring (ECG, blood pressure, oxygenation) is available.
- Why it is used: Your veterinarian may choose this specific anesthetic if your pet has a preexisting heart condition, head trauma, or is critically ill, because etomidate is very gentle on the cardiovascular system compared to other anesthetics.
- What to expect: It is used to safely induce sleep before a procedure. Because it does not provide pain relief on its own, your pet will receive additional pain medications as needed.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.