Opioids in anesthesia

Opioids are by far the oldest known analgesics, and their versatility in the practice of anesthesia and pain management remains unchallenged. It behooves any physician dealing with acute pain situations to have a working knowledge of the mechanisms through which opioids produce analgesia and the locations in the body where opioids work. Knowledge of the physical properties of the various opioids can help the practitioner predict how a given opioid will function when administered by a particular route, eg, epidural versus intravenous. In this article, the actions and properties of opioids will be reviewed with emphasis placed on their use in clinical practice.