etomidato

Etomidate is a short-acting intravenous hypnotic agent used primarily for the induction of anesthesia and for brief procedural sedation in both adults and children. It is valued for its ability to preserve cardiovascular stability compared with many other anesthetics, making it a common choice in patients with shock or limited cardiac reserve. Unlike some agents, etomidate provides hypnosis without substantial analgesia, so additional analgesia is typically required.

Etomidate acts as a positive allosteric modulator of the GABA-A receptor, enhancing inhibitory neurotransmission and producing loss of consciousness. Its onset is rapid, typically 30 to 60 seconds, and its duration of hypnosis is short, around 3 to 10 minutes, due to rapid redistribution and metabolism. It is primarily cleared by hepatic pathways and plasma esterases, with inactive metabolites. The context-sensitive half-time increases with longer or continuous infusions. A notable safety consideration is transient suppression of adrenal cortisol production after a single dose, caused by inhibition of 11-beta-hydroxylase; this suppression may persist for up to 24 hours and is a concern in severely ill or septic patients.

Common adverse effects include myoclonus during induction, respiratory depression and apnea, and pain on injection. Nausea and vomiting can occur after recovery. Cardiovascular effects are generally mild but hypotension can occur in some patients. Because of its adrenal suppressive effect, prolonged infusions are discouraged, and it is used mainly for induction rather than maintenance of anesthesia. Etomidate should be used with caution in patients with suspected adrenal insufficiency or significant hemodynamic instability, and care is taken to avoid excessive coadministration with other sedatives or opioids that can compound respiratory depression.