The alpha-2 receptor agonists (clonidine, dexmedetomidine) currently used in clinical practice have many desirable effects that may provide myocardial protection including analgesia, anxiolysis, inhibition of central sympathetic outflow and reduction of systemic norepinephrine release that improve hemodynamic stability and positively affect myocardial oxygen supply and demand. The most widely studied alpha-2 agonist is clonidine, a long-acting partial agonist with an alpha-2 to alpha-1 selectivity ratio of 39:1. However, dexmedetomidine is a highly selective, shorter-acting intravenous alpha-2 agonist with an alpha-2 to alpha-1 selectivity ratio of 1300:1.