Etomidate mechanism of action is shown here. The GABAA receptor plays a central role in the etomidate mechanism of action Etomidate exerts its effects on the receptor by binding directly to a specific site or sites on the protein and allosterically enhancing the apparent affinity of GABA for its receptor.
At much higher concentrations etomidate activate receptors in the absence of GABA. The ability of etomidate to modulate and activate GABAA receptors is uniquely dependent upon the beta subunit subtype present within the receptor.
However, GABA modulation and direct activation share stereoselectivity for the R(+) etomidate isomer. The R(+) isomer is much more effective than the S(-) isomer at potentiating GABA-induced currents.