Opioid Analgesics - Intravenous Anesthetics

OPIOID ANALGESICS

Opioids are analgesic agents and are distinct from general anesthet-ics and hypnotics. Even when high doses of opioid analgesics are administered, recall cannot be prevented reliably unless hypnotic agents such as benzodiazepines also are used. Opioid analgesics are routinely used to achieve postoperative analgesia and intraopera-tively as part of a balanced anesthesia regimen as described earlier (see Intravenous Anesthetics). In addition to their use as part of a balanced anesthesia regi-men, opioids in large doses have been used in combination with large doses of benzodiazepines to achieve a general anesthetic state, particularly in patients with limited circulatory reserve who undergo cardiac surgery. When administered in large doses, potent opioids such as fentanyl can induce chest wall (and laryngeal) rigidity, thereby acutely impairing mechanical ventilation. Furthermore, large doses of potent opioids may speed up the development of tolerance and complicate postoperative pain man-agement.