Episode Details

Etomidate (Amidate) is a short-acting sedative-hypnotic intravenous general anesthetic. Applying the 80/20 rule, this summary focuses on the core 20% of clinical details that deliver 80% of the practical knowledge needed for its safe administration:

1. Clinical Pharmacology & Mechanism

• Mechanism: Facilitates GABAminergic neurotransmission by increasing available GABA receptors, possibly by displacing endogenous inhibitors of GABA binding.
• Cerebral Effects: Reduces cerebral blood flow by 20% to 30%, lowers intracranial pressure (ICP) moderately for several minutes, and decreases intraocular pressure.
• Adrenal Impact: Inhibits steroidogenesis by blocking 11-beta-hydroxylation in the adrenal cortex, reducing plasma cortisol and aldosterone. This prevents its long-term use for ICU sedation.
• Pharmacokinetics: Onset of action is 0.5 to 1 minute, with a hypnotic duration of 3 to 5 minutes at a standard 0.3 mg/kg dose. It is 76% protein-bound, rapidly metabolized in the liver via ester hydrolysis, and has a 75-minute half-life.

2. Primary Indications & Dosing

• Anesthesia Induction: 0.2 to 0.6 mg/kg IV over 30 to 60 seconds (usual dose: 0.3 mg/kg).
• Subpotent Anesthetic Supplementation: 0.2 to 0.6 mg/kg IV over 30 to 60 seconds (usually lower than induction doses).
• Rapid-Sequence Intubation (RSI): 0.15 mg/kg IV for unstable patients and 0.3 mg/kg IV for stable patients. It is highly useful in head trauma, multiple traumas, cardiovascular disease, and non-sepsis hypotension as it lowers ICP with minimal systemic blood pressure impact.
• Procedural Sedation: 0.1 to 0.3 mg/kg IV (max: 20 mg/dose) over 30 to 60 seconds. Note: Etomidate does not have analgesic properties.
• Severe Hypercortisolism (Cushing's Syndrome): 0.04 to 0.1 mg/kg/hour IV infusion for ICU patients, or 0.025 mg/kg/hour for non-ICU patients.

3. Safety, Risks & Administration

• Administration: IV use only by trained personnel. Do not use for prolonged infusion.
• Adverse Reactions: Most common are myoclonia (74% incidence) and injection site reactions (1.2% to 42%). Severe reactions include apnea, laryngospasm, bradycardia, arrhythmia exacerbation, and anaphylactoid reactions. Adrenocortical insufficiency and hypoaldosteronism are potential delayed risks.
• Special Populations:
  • Renal/Hepatic Impairment: Lower doses may be needed, particularly with cirrhosis.
  • Lactation: Caution is advised. In post-Cesarean mothers, etomidate is excreted in colostrum but is undetectable by 4 hours; nursing is safe once the mother is awake and alert.