Etomidate has been used since 1972 as an inductor and in maintaining anesthesia. There are multiple mechanisms that account for the biologic effects of etomidate. One of the most prominent features of this drug is that it provides anesthesia without gross changes in hemodynamic parameters. This feature allows using etomidate in patients with considerable cardiopulmonary compromise avoiding the characteristic hypotension produced by other anesthetics. The mechanism that provides the basis for its cardiovascular stability is the capacity to bind and stimulate peripheral alpha-2B adrenergic receptors with a subsequent vasoconstriction. Alterations in the function or number of these receptors may account for abnormal responses during etomidate induction.