α2-adrenergic agonists produce sedation, anxiolysis, sympatholysis, and possess some analgesic properties because of the effect that decreasing the release of the norepinephrine in the sympathetic nerves ending of peripheral and central nervous system. The uses of α2-adrenergic agonists such as cloniding and dexmedetomidine in the peri-operative period produced sedation, analgesia, and maintained the hemodynamic state stable. At the same time, it decreased the opioids consumption and its side effects. The clinical uses of clonidine and dexmedetomidine still needs further study.