Introduction
Etomidate, a highly selective intravenous anesthetic agent, was first synthesized at Janssen Pharmaceuticals in the early 1964 and wasused for the induction of general anesthesia and sedation for short procedures such as reduction of tracheal intubation, cardioversion, and dislocated joints. Etomidate has the characteristics of being effective, fast, reliable and having curative effect. This drug also can cause adverse reactions such as forgetfulness, adrenocortical function suppression, which have been confirmed in recent years of clinical practice.
Pharmacologic action
Etomidate is a fast hypnotic intravenous general anesthesia drug with similar function of GABA, and its efficacy is 12 times more than that of thiopental sodium. Unlike sedative-hypnotics of barbiturates, this product causes the neocortex sleep at the beginning of the hypnotic effect and reduces cortex inhibition. Animal studies have shown that etomidate has partial effect on regulating the inhibition and activation of brainstem reticular system.
Function
Owing to the fact that etomidate has fewer side effects on the cardiovascular system and has advantages to maintain adequate myocardial blood supply after using the drug for patients, it has been widely applied in general anesthesia such as the heart and great vessels surgery. In addition, etomidate also possesses the profound clinical application prospect in the field of pediatric anesthesia. However, for patients who have been using etomidate for a long period of time, it may have an adverse reaction to adrenal function, and therefore, patients with severe infection and insufficient secretion of adrenaline need to be careful in using this drug.
Pharmacokinetics and metabolism
The serum concentration of etomidate was measured 10 hours after intravenous injection with a typical anesthetic induction dose (0.3 mg/kg) that produces rapid hypnosis and recovery occurs upon redistribution in adults. Within 1 min after intravenous injection, the concentration in brain tissue reaches 1.5±0.35 ug/g, which is higher than the blood drug concentration. It occurs in the lungs, kidneys, muscles, heart and spleen within two minutes, and reaches the fat, testicles and intestines around 7 to 28 minutes. Ultimately, etomidate is metabolized by hepatic esterase with a terminal half-life of approximately 5 hours; however, this value may be altered by hepatic or renal disease or extremes of age, leading to varying dosing requirements.
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