Etomidate is a short-acting intravenous anesthetic agent commonly used for induction of anesthesia and procedural sedation, particularly in critically ill or hemodynamically unstable patients due to its minimal cardiovascular effects.
While etomidate is generally safe in controlled settings, it does carry specific toxicities and risks, especially with repeated or prolonged use.
1. Adrenal Suppression (Most Significant Toxicity)
• Mechanism: Etomidate inhibits 11β-hydroxylase, a key enzyme in the adrenal steroidogenesis pathway.
• Effect: This leads to decreased cortisol and aldosterone production.
• Duration: Even a single dose can cause suppression lasting 6–24 hours.
• Clinical Concern: In critically ill or septic patients, this suppression may blunt the body’s stress response and worsen outcomes, especially if repeated doses are given.
2. Myoclonus and Seizure-Like Activity
• Description: Etomidate often causes involuntary muscle jerks (myoclonus) during induction.
• Not true seizures, but may be confused as such.
• Risk: Generally benign but may be problematic in patients with elevated intracranial pressure or open injuries.
3. Nausea and Vomiting
• More common during recovery from etomidate than with many other anesthetics.
4. Pain on Injection
• Etomidate can cause significant pain at the injection site, often requiring co-administration with lidocaine.
5. Respiratory Depression and Apnea
• Like other induction agents, etomidate can cause transient respiratory depression, especially at higher doses or in combination with other sedatives.
6. Hematologic or Hepatic Toxicity: Rare
• Etomidate is not associated with hepatic or renal toxicity and is generally considered safe from a metabolic standpoint, especially with single-dose use.
Clinical Bottom Line
• Safe for single-dose induction, particularly in unstable patients.
• Toxicity arises with repeated doses or infusions, especially due to adrenal suppression.
• It’s typically avoided in continuous sedation protocols, especially in septic or critically ill patients for this reason.
Would you like a comparison between etomidate and other induction agents (e.g., propofol, ketamine, thiopental) in terms of safety and toxicity?
