Perioperative use of selective alpha-2 agonists and antagonists in small animals.

Alpha-2 agonists are the only single class of anesthetic drugs that induce reliable, dose-dependent sedation, analgesia, and muscle relaxation in dogs and cats. Used at low doses, as adjuncts to injectable and inhalational anesthetics, selective alpha-2 agonists dramatically reduce the amount of anesthetic drug required to induce and maintain anesthesia. This reduction in anesthetic requirements is achieved without significant depression of pulmonary function and with limited effects on cardiovascular function. Selective alpha-2 agonists can also be used postoperatively to potentiate the analgesic effects of opioids and other drugs. Given the nearly ideal pharmacodynamic profile and reversibility of alpha-2 agonists, these drugs will play a central role in balanced approaches to anesthesia and the management of perioperative pain in healthy dogs and cats.