The pharmacological properties of etomidate (Amidate) are similar to those of the barbiturates, although its use may provide a greater margin of safety because of its limited effects on the cardiovascular and respiratory systems. Since it has a relatively short elimination half-life (t1/2 2.9 hours), in addition to its use as an induc- tion agent, etomidate has been used as a supplement to maintain anesthesia in some critically ill patients. Etomidate is rapidly hydrolyzed in the liver.
A primary advantage of etomidate is its ability to pre-serve cardiovascular and respiratory stability; both car-diac output and diastolic pressure are well maintained. Use of etomidate may offer some advantage to the pa-tient with compromised myocardial oxygen or blood supply or both, since it produces mild coronary vasodi-lation. Thus, coronary vascular resistance decreases with no change in perfusion pressure. Preservation of dia-stolic perfusion pressure may be particularly important when myocardial blood supply cannot be increased by autoregulation.
Etomidate may cause pain on injection and may pro-duce myoclonic muscle movements in approximately 40% of patients during its use as an induction anesthetic. In addition, etomidate can suppress the adrenocortical response to stress, an effect that may last up to 10 hours.