Remifentanil and other opioids.

Most opioids used in anaesthesia are of the anilidopiperidine family, including fentanyl, alfentanil, sufentanil and remifentanil. While all share similar pharmacological properties, remifentanil, the newest one, is probably the most original, which is the reason this review focusses especially on this drug. Remifentanil is a potent mu-agonist that retains all the pharmacodynamic characteristics of its class (regarding analgesia, respiratory depression, muscle rigidity, nausea and vomiting, pruritus, etc.) but with a unique pharmacokinetic profile that combines a short onset and the fastest offset, independent of the infusion duration. Consequently, it offers a unique titratability when its effects need to be quickly achieved or suppressed, but it requires specific drug delivery schemes such as continuous infusion, target-controlled infusion and anticipated postoperative pain treatment. Kinetic differences between opioids used in anaesthesia and some clinical uses of remifentanil are reviewed in this chapter.