Should etomidate be used in patients with adrenal insufficiency, and what stress‑dose glucocorticoid supplementation is recommended if it must be administered?

Etomidate and Adrenal Insufficiency

Etomidate should be avoided in patients with known adrenal insufficiency whenever possible, but if it must be used, administer hydrocortisone 100 mg intravenously at induction followed by continuous infusion of 200 mg per 24 hours until the patient can resume oral glucocorticoids. 1

Mechanism and Risk Profile

Etomidate rapidly and powerfully suppresses cortisol production by inhibiting 11-beta-hydroxylase, the enzyme catalyzing the final step in cortisol biosynthesis. 1, 2 This adrenal suppression:

• Occurs in 80% of critically ill patients within 12 hours of a single induction dose 3
• Persists for 6-8 hours according to FDA labeling, though research demonstrates suppression lasting up to 48 hours in most patients 2, 3
• Remains unresponsive to ACTH stimulation during the suppression period 2
• Creates particular danger in patients with pre-existing adrenal insufficiency, who lack any adrenal reserve 4

Clinical Decision-Making Algorithm

For Patients with Known Adrenal Insufficiency:

Step 1: Consider alternative induction agents first

• Propofol, ketamine, or midazolam do not suppress adrenal function 5
• The risk-benefit calculation strongly favors avoiding etomidate in this population 4

Step 2: If etomidate must be used (hemodynamic instability, no alternatives available):

• Before or at induction: Administer hydrocortisone 100 mg IV 1, 6
• Immediately following induction: Begin continuous IV infusion of hydrocortisone 200 mg per 24 hours 1, 6
• Continue infusion until the patient can tolerate oral intake 1
• Transition to oral: Double the patient's usual oral glucocorticoid dose for 48 hours, then return to maintenance 6

Step 3: Monitor aggressively for adrenal crisis:

• Volume-resistant hypotension is a late sign; earlier indicators include malaise, somnolence, orthostatic hypotension, and hyponatremia 1
• Maintain high suspicion and be prepared to immediately increase hydrocortisone dosing 1

For Patients on Chronic Glucocorticoids (≥5 mg prednisolone daily for ≥4 weeks):

These patients have potential HPA axis suppression and should be managed identically to those with confirmed adrenal insufficiency when receiving etomidate. 1, 6, 7

Evidence Regarding Single-Dose Etomidate

The guideline acknowledges conflicting evidence about single-dose etomidate before major surgery:

• Some in vivo studies did not suggest clinically-relevant changes from a single dose 1
• However, adverse outcomes have been documented with etomidate infusions 1
• Critical caveat: In septic shock patients specifically, etomidate increases relative adrenal insufficiency risk (odds ratio 5.59) and shows a trend toward increased mortality in those with predicted mortality >44% 8, 5

The guideline explicitly states "clinical judgement is required" but emphasizes that if doubt exists about the need for glucocorticoids, they should be given, as short-term administration has no long-term adverse consequences. 1, 6

Special Populations

Critically Ill and Septic Patients:

• Etomidate-induced adrenal suppression correlates with severity of illness 8
• In patients with predicted mortality >44%, the number needed to harm is 12.5 8
• Empirical steroid supplementation for 48 hours following etomidate should be considered in all ICU patients without septic shock 3
• In septic shock, corticosteroids should be started if etomidate is administered 5

Patients on CYP3A4 Inducers or Obese Patients:

• Higher hydrocortisone doses may be needed 1
• Preferably commence continuous infusion to reduce decompensation risk 1

Critical Pitfalls to Avoid

1. Do not rely on cortisol levels alone: Adrenal crisis can occur even with normal or elevated plasma cortisol during physiologic stress 6

2. Do not use dexamethasone alone in primary adrenal insufficiency: It lacks mineralocorticoid activity and is inadequate for stress coverage in these patients 1

3. Do not underestimate duration of suppression: While FDA labeling states 6-8 hours, research demonstrates 80% of patients have suppression at 12 hours, with significant suppression persisting at 48 hours 2, 3

4. Do not assume a single dose is safe in vulnerable patients: Case reports document acute adrenal crisis and cardiac arrest following single-dose etomidate in patients with pre-existing adrenal insufficiency 4

Practical Implementation

The safest approach: Treat all patients with known or suspected adrenal insufficiency receiving etomidate as if they will develop complete adrenal suppression. 1, 6 This means:

• Hydrocortisone 100 mg IV at induction 1, 6
• Continuous infusion 200 mg/24 hours (preferred over intermittent dosing for maintaining physiologic cortisol levels) 1
• Duration based on clinical course: minimum 48 hours for uncomplicated cases, up to one week for complicated recovery 1, 6