RESEARCH MONOGRAPH · KDC-MN-345

Etomidate

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

74/100

Hemodynamically stable hypnotic with an adrenal-suppression problem that wont go away

Here's the thing about etomidate. The hemodynamic stability is real and it's why anesthesiologists keep reaching for it in trauma and cardiac induction. Negligible drop in blood pressure or cardiac output at induction doses, which matters when your patient has nothing in the tank. The imidazole carboxylate structure produces clean GABA-A potentiation through a binding site that's partially distinct from propofol's, and the onset is quick.

But the adrenal suppression issue is real and has been since 1983 when Ledingham showed mortality bumps in ICU patients on etomidate infusions. The mechanism is direct inhibition of 11-beta hydroxylase in the cortisol synthesis pathway, and even a single induction dose suppresses cortisol response for 12 to 24 hours. The KETASED trial, the Jabre work, the meta-analyses, the signal keeps showing up.

Whether single-dose etomidate causes harm in septic patients is one of those debates that wont settle because the effect size is modest and the trials are noisy. Our read is that there's probably a real but small mortality signal in critically ill patients with marginal adrenal reserve, and most other patients are fine. But it's the kind of risk that drives the development of carboetomidate, methoxycarbonyl etomidate, and other ester-modified analogs designed to retain hypnotic activity while sparing adrenal suppression. Some interesting research compounds there.

Sourcing for research is fine. Small molecule, well-characterized, the propylene glycol formulation issue (the original) is now largely supplanted by lipid emulsion formulations clinically, but the pure compound is straightforward.

What we like for research is the binding site selectivity work. Etomidate has been a really useful tool for mapping GABA-A subunit contributions to hypnosis, particularly the beta-3 vs beta-2 story (Rudolph, Forman labs). The transgenic knockin work using etomidate-insensitive beta-3 mice is some of the cleanest mechanistic anesthesia pharmacology in the literature.

The bigger question is staying power. With dex, ketamine, and propofol covering most use cases and the adrenal issue being a continued concern, etomidate's clinical role is narrower than it used to be. As a research tool, though, it's not going anywhere.

Evidence: 85
Mechanism: 85
Reliability: 82
Safety: 55
Sourcing: 80
Value: 70
Signal: 70
Staying power: 65

Plain-language summary Intrigue 54 / 100

Etomidate is an intravenous induction anesthetic used when cardiovascular stability matters most, such as in trauma patients with low blood pressure or those with significant heart disease. It enhances GABA-A signaling at a different site than propofol and produces minimal blood pressure or heart rate changes. The major liability is adrenocortical suppression: etomidate inhibits the 11-beta-hydroxylase enzyme that synthesizes cortisol, and even a single induction dose meaningfully suppresses cortisol production for up to 24 hours. This has limited its use in septic patients, where adrenal suppression is harmful. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

GABA-A receptor positive allosteric modulator (intravenous anesthetic)

An imidazole intravenous induction anesthetic; cardiovascular stable but causes adrenocortical suppression.

Abstract

Etomidate ((R)-1-(1-phenylethyl)-1H-imidazole-5-carboxylic acid ethyl ester; CAS 33125-97-2; molecular formula C14H16N2O2; molecular weight 244.29) is an imidazole intravenous induction anesthetic developed at Janssen and approved by the FDA in 1972 (Amidate). The compound is a GABA-A receptor positive allosteric modulator with a binding site at the beta-2 and beta-3 subunits that produces preferential activity at extrasynaptic and synaptic GABA-A receptors. Distinct among IV anesthetics by minimal cardiovascular effects (preserved blood pressure and heart rate), making it preferred for patients with hemodynamic instability. The principal limitation is dose-dependent inhibition of 11-beta-hydroxylase (CYP11B1), the final enzyme in cortisol biosynthesis; even a single induction dose suppresses cortisol for 4 to 6 hours, with potential clinical consequence in critically ill patients. Plasma half-life is approximately 2 to 5 hours. Used as a reference IV anesthetic with cardiovascular stability and adrenocortical suppression.

Mechanism of action

GABA-A receptor positive allosteric modulator at beta-2/3 subunit binding site. Cardiovascular stable. Inhibits 11-beta-hydroxylase, suppressing cortisol synthesis.

Reported research dose ranges

Clinical induction 0.2 to 0.6 mg/kg IV.

References

Forman SA. Clinical and molecular pharmacology of etomidate. Anesthesiology 2011.
Cuthbertson BH, et al. The effects of etomidate on adrenal responsiveness and mortality in patients with septic shock. Intensive Care Med 2009.
Vanlersberghe C, Camu F. Etomidate and other non-barbiturates. Handb Exp Pharmacol 2008.

Read the full monograph

The full reference document is available as a research-use-only PDF download. Note: PDFs for newly added compounds may take a few hours to propagate after this article was published.

KDC-MN-345

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

Download PDF →

FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

Kodiac sells research compounds for investigative use only.

Etomidate

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

Quick actions

Categories

Help and policies

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

Adjacent monographs