Clonidine and other alpha2 adrenergic agonists: strategies for the rational use of these novel anesthetic agents.

Clonidine and other clinically available alpha-2 adrenergic agonists reduce inhalational and narcotic anesthetic requirements while providing hemodynamic stability during stressful periods of surgery. Like the opiates, the alpha-2 adrenergic agonists are potent analgesics when given systemically, epidurally, or intrathecally. Their effects are reversed by alpha2 adrenergic antagonists. Newer and more selective alpha2 adrenergic agonists are more potent in their anesthetic action than the clinically available opiates. The important difference is that these agents do not appear to be respiratory depressants and do not have an addiction liability of the opioid type. They have anxiolytic properties and therefore can be potentially useful in the preanesthetic period. This drug class has the potential to provide many of the component effects required for perioperative care. For these reasons, the alpha2 adrenergic class of drugs should be important in the future of anesthesia.