ETOMIDATE 

1. BASIC PHARMACOLOGY

Etomidate is a non-barbiturate imidazole derivative used primarily for induction of anesthesia, especially in hemodynamically unstable patients.

Key Properties

• Ultra–short acting hypnotic (no analgesia)
• Highly cardiovascularly stable
• Minimal respiratory depression (compared to other agents)
• Strong adrenal suppression effect

2. MECHANISM OF ACTION

• Potentiates GABA-A receptor
• ↑ Chloride influx → neuronal hyperpolarization → hypnosis

 No analgesic effect → must combine with opioids if needed

 3. PHARMACOKINETICS

 4. DOSING IN ICU 

 Induction (RSI / Intubation)

• 0.2–0.3 mg/kg IV bolus
• Reduce dose in:
• Elderly
• Shock (0.15–0.2 mg/kg)

 Continuous infusion  (AVOID)

• NOT recommended due to adrenal suppression

5. HEMODYNAMIC PROFILE

 Best induction agent in:

• Septic shock
• Cardiogenic shock
• Trauma with hypotension

 6. CNS EFFECTS

• ↓ Cerebral metabolic rate (CMRO₂)
• ↓ ICP
• Maintains CPP

 Useful in:

• Traumatic brain injury (TBI)
• Neurocritical care

 7. RESPIRATORY EFFECTS

• Mild respiratory depression
• Preserves airway reflexes better than propofol

 8. ADRENAL SUPPRESSION 

Mechanism

• Inhibits 11-β-hydroxylase + 17-α-hydroxylase
• ↓ Cortisol + aldosterone synthesis

Duration

• After single bolus: 6–24 hours suppression

Clinical Impact

• Controversial in:
• Septic shock
• Critically ill patients

Evidence 

• Transient suppression documented
• Mortality impact unclear (conflicting RCTs/meta-analyses)
• Guidelines caution but do NOT absolutely contraindicate single dose

 9. GUIDELINE RECOMMENDATIONS

 Surviving Sepsis Campaign

• Avoid routine use in septic shock if alternatives available
• Single-dose acceptable if hemodynamically unstable

Society of Critical Care Medicine

• Etomidate acceptable for RSI
• Be aware of adrenal suppression

 10. CLINICAL INDICATIONS IN ICU

 Preferred situations

• Hemodynamic instability
• Shock (septic, cardiogenic, hemorrhagic)
• TBI with hypotension
• Emergency RSI

 Avoid / caution

• Septic shock (relative)
• Adrenal insufficiency
• Long-term sedation

 11. ADVERSE EFFECTS

Common

• Myoclonus (30–60%)
• Injection pain (less than propofol)
• Nausea/vomiting

Serious

• Adrenal suppression 
• Seizure-like activity (non-epileptic myoclonus)
• Rare anaphylaxis

12. MYOCLONUS 

• Occurs due to disinhibition of subcortical centers
• Prevention:
• Small dose benzodiazepine (e.g., Midazolam)
• Opioid pre-treatment

13. COMPARISON WITH OTHER INDUCTION AGENTS